fix(installer): complete literal paths and recovery guidance

fix(geometry): preserve OOPIF scale with occupied scrollbars

.github/workflows/ci.yml

@@ -38,7 +38,7 @@ jobs:
         run: cargo test --workspace --locked
 
   windows-daemon:
-    name: Windows daemon and update regression tests
+    name: Windows daemon, installer and cancellation regression tests
     runs-on: windows-latest
 
     steps:
@@ -55,8 +55,16 @@ jobs:
       - name: Run Windows update tests
         run: cargo test -p bsk --lib --locked cli::update::tests
 
-      - name: Run Windows update process tests
-        run: cargo test -p bsk --test windows_update --locked
+      - name: Run Windows update and cancellation process tests
+        run: cargo test -p bsk --test windows_update --test windows_parent_cancel --locked
+
+      - name: Run installer tests (Windows PowerShell 5.1)
+        shell: powershell
+        run: ./scripts/install-windows.test.ps1
+
+      - name: Run installer tests (PowerShell 7)
+        shell: pwsh
+        run: ./scripts/install-windows.test.ps1
 
   frontend:
     name: Frontend lint, typecheck, tests, build

CHANGELOG.md

@@ -5,7 +5,24 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/).
 
 Starting from 0.2.0, CLI / Extension / DSH Plugin share the same version number.
 
-## [Unreleased]
+## [0.2.1] - 2026-09-09
+
+### Changed
+- DSH Plugin: clarified installation, configuration, profile restart, and upgrade instructions
+
+### Fixed
+- CLI: reliable Windows self-updates, including executable replacement and daemon restart
+- CLI: Windows named-pipe connection continuity and stale daemon process detection
+- Windows installer: PowerShell 5.1 compatibility, path quoting, and staged executable replacement
+- CLI / DSH Plugin: cancellation propagation and upload/download cleanup when the parent process exits
+- Extension: tab ownership and session cleanup when agent tabs fail to open or borrowed tabs are returned or closed
+- Extension: navigation recovery when other extensions restrict Chrome DevTools Protocol access
+- Extension: background input filling, automatic append behavior, and verification of field values before reporting success
+- Extension: match observed form state to the correct element after page changes
+- Extension: UUID generation fallback for recording and overlays on insecure origins
+- Browser locale matching for regional language variants
+- DSH Plugin: observation state synchronization, thumbnail capture lifecycle, and stale preview cleanup
+- DSH Plugin: removed the obsolete client runtime host dependency
 
 ## [0.2.0] - 2026-09-02
 

Cargo.lock

@@ -134,7 +134,7 @@ dependencies = [
 
 [[package]]
 name = "bsk"
-version = "0.2.0"
+version = "0.2.1"
 dependencies = [
  "anyhow",
  "base64",
@@ -169,7 +169,7 @@ dependencies = [
 
 [[package]]
 name = "bsk-protocol"
-version = "0.2.0"
+version = "0.2.1"
 dependencies = [
  "schemars",
  "semver",

Cargo.toml

@@ -7,7 +7,7 @@ members = [
 default-members = ["crates/bsk-cli"]
 
 [workspace.package]
-version = "0.2.0"
+version = "0.2.1"
 edition = "2024"
 rust-version = "1.85"
 license = "MIT"
@@ -43,7 +43,7 @@ rand = "0.8"
 uuid = { version = "1", features = ["v4", "serde"] }
 
 # Workspace crates (version required for `cargo publish` of dependents)
-bsk-protocol = { version = "0.2.0", path = "crates/bsk-protocol" }
+bsk-protocol = { version = "0.2.1", path = "crates/bsk-protocol" }
 
 [profile.release]
 strip = "symbols"

README.md

@@ -147,20 +147,26 @@ Start a new Agent session and write a prompt that needs the browser, for example
 Using [DeepSeek Harness](https://github.com/deepseek-ai/deepseek-harness) (`dsh`)?
 BrowserSkill ships a first-class dsh plugin on npm as
 [`@wxg-prc-cpg/browser-skill-dsh-plugin`](https://www.npmjs.com/package/@wxg-prc-cpg/browser-skill-dsh-plugin).
-It injects native `browser_*` tools (no shelling out to `bsk`) and a live Web UI
-overlay of each Agent Window.
+It gives the agent native `browser_*` tools and a live view of its browser sessions
+in the Web UI. The plugin runs `bsk` on the agent's behalf.
 
-Add it to a dsh profile, then start that profile:
+Install the `bsk` CLI and connect the browser extension first. Then add the plugin
+to a dsh profile and start it (replace `web` with your profile name):
 
 ```sh
 dsh plugin --profile web add @wxg-prc-cpg/browser-skill-dsh-plugin
 dsh --profile web
 ```
 
-The plugin carries its own copy of the skill, so `bsk install-skill` is not needed
-for dsh — but the `bsk` CLI and the browser extension are still prerequisites. See
-the [plugin README](packages/dsh-plugin-browserskill/README.md) for the tool list,
-configuration, and the observation overlay.
+The plugin includes the `browser-skill` skill, so `bsk install-skill` is not needed
+for dsh. Installed plugins do not update automatically. To upgrade this plugin:
+
+```sh
+dsh plugin --profile web update @wxg-prc-cpg/browser-skill-dsh-plugin --latest
+```
+
+Restart the profile after upgrading. See the
+[plugin README](packages/dsh-plugin-browserskill/README.md) for usage and configuration.
 
 ## How It Works
 

README.zh-CN.md

@@ -125,16 +125,22 @@ bsk install-skill
 
 ## DeepSeek Harness 插件
 
-在用 [DeepSeek Harness](https://github.com/deepseek-ai/deepseek-harness)（`dsh`）？BrowserSkill 提供了官方 dsh 插件，已发布到 npm：[`@wxg-prc-cpg/browser-skill-dsh-plugin`](https://www.npmjs.com/package/@wxg-prc-cpg/browser-skill-dsh-plugin)。它会注入原生 `browser_*` 工具（无需再通过 Shell 调用 `bsk`），并在 Web UI 中实时观察每个 Agent Window。
+在用 [DeepSeek Harness](https://github.com/deepseek-ai/deepseek-harness)（`dsh`）？BrowserSkill 提供了官方 dsh 插件，已发布到 npm：[`@wxg-prc-cpg/browser-skill-dsh-plugin`](https://www.npmjs.com/package/@wxg-prc-cpg/browser-skill-dsh-plugin)。它为 Agent 提供原生 `browser_*` 工具，由插件代为调用 `bsk`，并在 Web UI 中实时展示浏览器会话。
 
-把它装进某个 dsh profile，然后启动该 profile：
+先安装 `bsk` CLI 并连接浏览器扩展，再将插件装进 dsh profile 并启动（将 `web` 替换为你的 profile 名称）：
 
 ```sh
 dsh plugin --profile web add @wxg-prc-cpg/browser-skill-dsh-plugin
 dsh --profile web
 ```
 
-插件自带 skill，所以在 dsh 下无需执行 `bsk install-skill`；但 `bsk` CLI 和浏览器扩展仍是前置条件。工具清单、配置项与观察浮层见[插件 README](packages/dsh-plugin-browserskill/README.md)。
+插件自带 `browser-skill` skill，所以在 dsh 下无需执行 `bsk install-skill`。已安装的插件不会自动更新；升级此插件请运行：
+
+```sh
+dsh plugin --profile web update @wxg-prc-cpg/browser-skill-dsh-plugin --latest
+```
+
+升级后重启该 profile。用法与配置见[插件 README](packages/dsh-plugin-browserskill/README.md)。
 
 ## 工作原理
 

apps/extension/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@browser-skill/extension",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "private": true,
   "type": "module",
   "scripts": {

apps/extension/src/browser-driver/__tests__/chromium-cdp.test.ts

@@ -29,6 +29,24 @@ function fakeApi() {
 }
 
 describe("ChromiumCdp", () => {
+  it("changes attachment identity only across real debugger attachments", async () => {
+    const { api, onEvent, onDetach } = fakeApi();
+    const cdp = new ChromiumCdp(api);
+    expect(cdp.getAttachmentId(4)).toBeUndefined();
+    await cdp.ensureAttached(4);
+    const first = cdp.getAttachmentId(4);
+    expect(first).toBeTruthy();
+    await cdp.ensureAttached(4);
+    onEvent.fire({ tabId: 4 }, "Target.attachedToTarget", { sessionId: "child" });
+    expect(cdp.getAttachmentId(4)).toBe(first);
+    onDetach.fire({ tabId: 4 }, "target_closed");
+    expect(cdp.getAttachmentId(4)).toBeUndefined();
+    await cdp.ensureAttached(4);
+    expect(cdp.getAttachmentId(4)).not.toBe(first);
+    await cdp.detach(4);
+    expect(cdp.getAttachmentId(4)).toBeUndefined();
+  });
+
   it("discovers multiple iframe targets and recursively routes nested OOPIF commands", async () => {
     const { api, onEvent } = fakeApi();
     (api.sendCommand as ReturnType<typeof vi.fn>).mockImplementation(

apps/extension/src/browser-driver/chromium-cdp.ts

@@ -164,6 +164,7 @@ async function settleBeforeDeadline(promises: Promise<void>[], deadline: number)
 export class ChromiumCdp {
   private readonly api: CdpDebuggerApi;
   private readonly attachedTabs = new Set<number>();
+  private readonly attachmentIds = new Map<number, string>();
   private readonly attachInFlight = new Map<number, Promise<void>>();
   private readonly detachInFlight = new Map<number, Promise<void>>();
   private readonly tabOwners = new Map<number, Set<string>>();
@@ -198,6 +199,11 @@ export class ChromiumCdp {
     this.bindFrameTargetHandler();
   }
 
+  /** Identity of this actual debugger attachment, independent of frame topology. */
+  getAttachmentId(tabId: number): string | undefined {
+    return this.attachmentIds.get(tabId);
+  }
+
   /** Attach to `tabId` if we haven't already in this driver. */
   async ensureAttached(tabId: number): Promise<void> {
     // Returning a tab clears the cache before Chrome finishes detaching.
@@ -217,6 +223,7 @@ export class ChromiumCdp {
         await this.enableConsoleDomains(tabId);
         await this.enableNetworkDomainBestEffort(tabId);
         this.attachedTabs.add(tabId);
+        this.attachmentIds.set(tabId, crypto.randomUUID());
         await this.enableFrameDiscovery({ tabId }).catch((err) => {
           console.debug("[bsk cdp] frame discovery unavailable", { tabId, err });
         });
@@ -444,6 +451,7 @@ export class ChromiumCdp {
     this.attachInFlight.delete(tabId);
     if (!this.attachedTabs.has(tabId)) return;
     this.attachedTabs.delete(tabId);
+    this.attachmentIds.delete(tabId);
     this.clearDialogState(tabId);
     this.clearConsoleState(tabId);
     this.clearNetworkState(tabId);
@@ -502,6 +510,7 @@ export class ChromiumCdp {
     this.attachInFlight.clear();
     this.tabOwners.clear();
     this.attachedTabs.clear();
+    this.attachmentIds.clear();
     this.dialogBuffers.clear();
     this.dialogSequences.clear();
     this.consoleBuffers.clear();
@@ -848,6 +857,7 @@ export class ChromiumCdp {
     const listener = (source: chrome.debugger.Debuggee, _reason: string) => {
       if (typeof source.tabId === "number") {
         this.attachedTabs.delete(source.tabId);
+        this.attachmentIds.delete(source.tabId);
         this.attachInFlight.delete(source.tabId);
         this.tabOwners.delete(source.tabId);
         this.clearDialogState(source.tabId);

apps/extension/src/tools/__tests__/file-transfer.test.ts

@@ -436,6 +436,8 @@ describe("file transfer tools", () => {
         if (method === "DOM.getContentQuads") {
           return { quads: [[10, 20, 210, 20, 210, 120, 10, 120]] };
         }
+        if (method === "Runtime.evaluate")
+          return { result: { value: { width: 400, height: 300 } } };
         if (method === "Page.getLayoutMetrics") {
           return { cssLayoutViewport: { clientWidth: 400, clientHeight: 300 } };
         }

apps/extension/src/tools/__tests__/frame-geometry.test.ts

@@ -13,7 +13,138 @@ import {
 import { GeometryContext } from "../geometry/frame-context";
 import type { CdpRunner } from "../shared";
 
+function scrollbarDriver(
+  visible = { width: 185, height: 89 },
+  frameSize: unknown = { width: 200, height: 100 },
+) {
+  const send = vi.fn(async (target: { sessionId?: string }, method: string) => {
+    if (method === "Runtime.evaluate") return { result: { value: frameSize } };
+    if (method === "Page.getLayoutMetrics")
+      return {
+        cssLayoutViewport: {
+          clientWidth: target.sessionId ? visible.width : 800,
+          clientHeight: target.sessionId ? visible.height : 600,
+        },
+      };
+    if (method === "DOM.getBoxModel")
+      return {
+        model: {
+          content: target.sessionId
+            ? [0, 0, 200, 0, 200, 100, 0, 100]
+            : [100, 100, 500, 100, 500, 300, 100, 300],
+        },
+      };
+    if (method === "DOM.getContentQuads")
+      return { quads: [[180, 80, 230, 80, 230, 120, 180, 120]] };
+    throw new Error(`unexpected ${method}`);
+  });
+  const cdp: CdpRunner = {
+    send: (tabId, method) => send({ tabId } as never, method) as never,
+    sendToTarget: send as CdpRunner["sendToTarget"],
+    getFrameGraph: async () => ({
+      rootFrameId: "main",
+      frames: [
+        { frameId: "main", target: { tabId: 4 } },
+        {
+          frameId: "child",
+          parentFrameId: "main",
+          ownerBackendNodeId: 10,
+          target: { tabId: 4, sessionId: "child" },
+        },
+        {
+          frameId: "same-child",
+          parentFrameId: "child",
+          ownerBackendNodeId: 20,
+          target: { tabId: 4, sessionId: "child" },
+        },
+      ],
+    }),
+  };
+  return { cdp, send };
+}
+
 describe("frame geometry projection", () => {
+  it.each([
+    { width: 200, height: 100 },
+    { width: 185, height: 100 },
+    { width: 200, height: 89 },
+    { width: 185, height: 89 },
+  ])("preserves scale and clips scrollbar strips for visible viewport $width × $height", async (visible) => {
+    const { cdp, send } = scrollbarDriver(visible);
+    const geometry = await resolveNodeGeometry(cdp, 4, {
+      target: { tabId: 4, sessionId: "child" },
+      frameId: "child",
+      backendNodeId: 101,
+    });
+    expect(geometry).toMatchObject({
+      topBounds: {
+        x: 460,
+        y: 260,
+        width: (visible.width - 180) * 2,
+        height: (visible.height - 80) * 2,
+      },
+      actionPoint: { x: 460 + visible.width - 180, y: 260 + visible.height - 80 },
+      targetActionPoint: { x: (180 + visible.width) / 2, y: (80 + visible.height) / 2 },
+    });
+    expect(send.mock.calls.filter(([, method]) => method === "Runtime.evaluate")).toHaveLength(1);
+    expect(send.mock.calls.filter(([, method]) => method === "Page.getLayoutMetrics")).toHaveLength(
+      2,
+    );
+  });
+
+  it("shares the full viewport read across same-target frames, and refreshes it next operation", async () => {
+    const { cdp, send } = scrollbarDriver();
+    const context = new GeometryContext(cdp, 4);
+    await Promise.all([context.targetProjection("child"), context.targetProjection("same-child")]);
+    expect(send.mock.calls.filter(([, method]) => method === "Runtime.evaluate")).toHaveLength(1);
+    await new GeometryContext(cdp, 4).targetProjection("child");
+    expect(send.mock.calls.filter(([, method]) => method === "Runtime.evaluate")).toHaveLength(2);
+  });
+
+  it.each([
+    null,
+    {},
+    { width: 0, height: 100 },
+    { width: 200, height: NaN },
+  ])("rejects unavailable full viewport dimensions: %j", async (size) => {
+    const { cdp } = scrollbarDriver(undefined, size);
+    expect(await new GeometryContext(cdp, 4).targetProjection("child")).toBeNull();
+  });
+
+  it("clips an inner OOPIF against an intermediate OOPIF's occupied scrollbar strips", async () => {
+    const { cdp } = scrollbarDriver();
+    const outer = cdp.sendToTarget!;
+    cdp.sendToTarget = async (target, method, params) => {
+      if (method === "DOM.getBoxModel")
+        return { model: { content: [150, 60, 250, 60, 250, 120, 150, 120] } } as never;
+      if (target.sessionId !== "inner") return outer(target, method, params);
+      if (method === "Runtime.evaluate")
+        return { result: { value: { width: 100, height: 60 } } } as never;
+      if (method === "Page.getLayoutMetrics")
+        return { cssLayoutViewport: { clientWidth: 90, clientHeight: 50 } } as never;
+      if (method === "DOM.getContentQuads")
+        return { quads: [[0, 0, 100, 0, 100, 60, 0, 60]] } as never;
+      throw new Error(`unexpected ${method}`);
+    };
+    const graph = await cdp.getFrameGraph!(4);
+    graph.frames[2] = {
+      frameId: "inner",
+      parentFrameId: "child",
+      ownerBackendNodeId: 20,
+      target: { tabId: 4, sessionId: "inner" },
+    };
+    cdp.getFrameGraph = async () => graph;
+    expect(
+      await resolveNodeGeometry(cdp, 4, {
+        target: { tabId: 4, sessionId: "inner" },
+        frameId: "inner",
+        backendNodeId: 101,
+      }),
+    ).toMatchObject({
+      topBounds: { x: 400, y: 220, width: 70, height: 58 },
+    });
+  });
+
   it("keeps region bounds separate from polygon area", () => {
     const region = [
       rectPolygon({ x: 0, y: 0, w: 10, h: 10 }),
@@ -77,6 +208,8 @@ describe("frame geometry projection", () => {
     const cdp: CdpRunner = {
       send: send as CdpRunner["send"],
       sendToTarget: vi.fn(async (_target, method) => {
+        if (method === "Runtime.evaluate")
+          return { result: { value: { width: 200, height: 100 } } };
         if (method === "Page.getLayoutMetrics") {
           return { cssLayoutViewport: { clientWidth: 200, clientHeight: 100 } };
         }
@@ -135,6 +268,8 @@ describe("frame geometry projection", () => {
         throw new Error(`unexpected root command ${method}`);
       }) as CdpRunner["send"],
       sendToTarget: vi.fn(async (_target, method) => {
+        if (method === "Runtime.evaluate")
+          return { result: { value: { width: 200, height: 100 } } };
         if (method === "Page.getLayoutMetrics") {
           return { cssLayoutViewport: { clientWidth: 200, clientHeight: 100 } };
         }
@@ -196,6 +331,8 @@ describe("frame geometry projection", () => {
       }) as CdpRunner["send"],
       sendToTarget: vi.fn(async (_target, method) => {
         if (method === "DOM.scrollIntoViewIfNeeded") return {};
+        if (method === "Runtime.evaluate")
+          return { result: { value: { width: 200, height: 100 } } };
         if (method === "Page.getLayoutMetrics") {
           return { cssLayoutViewport: { clientWidth: 200, clientHeight: 100 } };
         }

apps/extension/src/tools/__tests__/geometry-context.test.ts

@@ -5,9 +5,10 @@ import { rectPolygon } from "../geometry";
 import {
   projectSnapshotRect,
   screenshotPageRect,
+  snapshotCoordinates,
   snapshotViewportRect,
 } from "../geometry/coordinate-types";
-import { GeometryContext } from "../geometry/frame-context";
+import { GeometryContext, snapshotLayoutScale } from "../geometry/frame-context";
 import type { CdpRunner } from "../shared";
 
 const target = { tabId: 4 };
@@ -22,7 +23,11 @@ const graph: CdpFrameGraph = {
 function driver() {
   const send = vi.fn(async (_tab: number, method: string): Promise<object> => {
     if (method === "Page.getLayoutMetrics")
-      return { cssLayoutViewport: { clientWidth: 1000, clientHeight: 1000 } };
+      return {
+        visualViewport: { clientWidth: 1000 },
+        cssVisualViewport: { clientWidth: 1000 },
+        cssLayoutViewport: { clientWidth: 1000, clientHeight: 1000 },
+      };
     if (method === "DOM.getBoxModel")
       return { model: { content: [52.5, 612.5, 427.5, 612.5, 427.5, 862.5, 52.5, 862.5] } };
     if (method === "DOM.resolveNode") return { object: { objectId: "owner" } };
@@ -35,6 +40,63 @@ function driver() {
 }
 
 describe("measurement geometry context", () => {
+  it.each([0.8, 1, 1.25, 2])("normalizes snapshot layout units at scale %s", (scale) => {
+    const measured = snapshotLayoutScale({
+      visualViewport: { clientWidth: 997.25, zoom: 1.1 },
+      cssVisualViewport: { clientWidth: 997.25 / scale, zoom: 1.1 },
+      // Rounded layout dimensions must not supply the scale.
+      layoutViewport: { clientWidth: 997 },
+      cssLayoutViewport: { clientWidth: Math.floor(997.25 / scale) },
+    });
+    expect(measured).toBeCloseTo(scale, 12);
+    const coordinates = snapshotCoordinates(
+      { scrollOffsetX: 80 * scale, scrollOffsetY: 200 * scale },
+      measured,
+      { x: 999, y: 999 },
+    );
+    expect(
+      snapshotViewportRect(
+        [160 * scale, 320 * scale, 120 * scale, 40 * scale],
+        { target },
+        coordinates,
+      )?.rect,
+    ).toEqual({ x: 80, y: 120, width: 120, height: 40 });
+  });
+
+  it("uses CSS root scroll only for missing snapshot offsets, without scaling it twice", () => {
+    const coordinates = snapshotCoordinates({ scrollOffsetX: 80 }, 2, { x: 999, y: 100 });
+    expect(snapshotViewportRect([200, 800, 240, 80], { target }, coordinates)?.rect).toEqual({
+      x: 60,
+      y: 300,
+      width: 120,
+      height: 40,
+    });
+    expect(snapshotCoordinates({ scrollOffsetX: 0 }, 2)).toBeNull();
+    expect(
+      snapshotCoordinates({ scrollOffsetX: NaN, scrollOffsetY: 0 }, 2, { x: 0, y: 0 }),
+    ).toBeNull();
+  });
+
+  it("does not infer snapshot units from missing, invalid, or CSS-only metrics", () => {
+    expect(snapshotLayoutScale({ cssLayoutViewport: { clientWidth: 800 } })).toBeNull();
+    for (const raw of [0, -1, NaN, Infinity]) {
+      expect(
+        snapshotLayoutScale({
+          visualViewport: { clientWidth: raw },
+          cssVisualViewport: { clientWidth: 800 },
+        }),
+      ).toBeNull();
+    }
+    expect(
+      snapshotLayoutScale({
+        visualViewport: { clientWidth: 0, clientHeight: 600 },
+        cssVisualViewport: { clientWidth: 0, clientHeight: 300 },
+      }),
+    ).toBe(2);
+    expect(snapshotCoordinates({ scrollOffsetX: 0, scrollOffsetY: 0 }, null)).toBeNull();
+    expect(snapshotViewportRect([10, 20, 120, 40], { target }, null)).toBeNull();
+  });
+
   it("shares in-flight frame measurements, but never shares them with the next context", async () => {
     const cdp = driver();
     const context = new GeometryContext(cdp, 4);
@@ -61,14 +123,20 @@ describe("measurement geometry context", () => {
       height: 1000,
     });
     if (projection.status !== "available") throw new Error("expected available projection");
-    const input = snapshotViewportRect([17, 23, 120, 40], source, { x: 0, y: 0 });
+    const input = snapshotViewportRect([17, 23, 120, 40], source, {
+      layoutUnitsPerCssPixel: 1,
+      scrollCss: { x: 0, y: 0 },
+    });
     expect(projectSnapshotRect(input!, projection.projection)).toEqual({
       x: 73.75,
       y: 641.25,
       width: 150,
       height: 50,
     });
-    const scrolled = snapshotViewportRect([17, 23, 120, 40], source, { x: 0, y: 10 });
+    const scrolled = snapshotViewportRect([17, 23, 120, 40], source, {
+      layoutUnitsPerCssPixel: 1,
+      scrollCss: { x: 0, y: 10 },
+    });
     expect(projectSnapshotRect(scrolled!, projection.projection)?.y).toBe(628.75);
     await context.snapshotProjection(source, 10, [], { width: 1000, height: 1000 });
     expect(cdp.calls.mock.calls.filter(([, method]) => method === "DOM.resolveNode")).toHaveLength(
@@ -79,11 +147,101 @@ describe("measurement geometry context", () => {
     ).toHaveLength(1);
   });
 
+  it("falls back only for missing or invalid batch entries and does not reuse sizes across contexts", async () => {
+    const cdp = driver();
+    const original = cdp.send;
+    const calls: string[] = [];
+    cdp.send = async (tabId, method, params) => {
+      calls.push(method);
+      if (method === "Runtime.evaluate")
+        return {
+          result: {
+            deepSerializedValue: {
+              type: "array",
+              value: [
+                {
+                  type: "array",
+                  value: [
+                    { type: "node", value: { backendNodeId: 10 } },
+                    { type: "string", value: '{"width":300,"height":200}' },
+                  ],
+                },
+                {
+                  type: "array",
+                  value: [
+                    { type: "node", value: { backendNodeId: 11 } },
+                    { type: "string", value: '{"width":0,"height":200}' },
+                  ],
+                },
+              ],
+            },
+          },
+        } as never;
+      if (method === "Runtime.releaseObjectGroup") return {} as never;
+      return original(tabId, method, params);
+    };
+    const context = new GeometryContext(cdp, 4);
+    context.registerSnapshotOwners(target, new Set([10, 11]));
+    const values = await Promise.all(
+      [10, 11].map((id) =>
+        context.snapshotProjection({ target, frameId: String(id) }, id, [], {
+          width: 1000,
+          height: 1000,
+        }),
+      ),
+    );
+    expect(values.every((value) => value.status === "available")).toBe(true);
+    expect(calls.filter((method) => method === "DOM.resolveNode")).toHaveLength(1);
+    expect(calls.filter((method) => method === "Runtime.evaluate")).toHaveLength(1);
+    await new GeometryContext(cdp, 4).snapshotProjection({ target, frameId: "child" }, 10, [], {
+      width: 1000,
+      height: 1000,
+    });
+    expect(calls.filter((method) => method === "DOM.resolveNode")).toHaveLength(2);
+  });
+
+  it("waits for batch object cleanup and propagates cancellation", async () => {
+    const cdp = driver();
+    const original = cdp.send;
+    const controller = new AbortController();
+    let release!: () => void;
+    let cleanup!: () => void;
+    const started = new Promise<void>((resolve) => {
+      cleanup = resolve;
+    });
+    cdp.send = async (tabId, method, params) => {
+      if (method === "Runtime.evaluate") return {} as never;
+      if (method === "Runtime.releaseObjectGroup") {
+        cleanup();
+        await new Promise<void>((resolve) => {
+          release = resolve;
+        });
+        return {} as never;
+      }
+      return original(tabId, method, params);
+    };
+    const context = new GeometryContext(cdp, 4, undefined, controller.signal);
+    context.registerSnapshotOwners(target, new Set([10, 11]));
+    let settled = false;
+    const operation = context
+      .snapshotProjection({ target, frameId: "child" }, 10, [], { width: 1000, height: 1000 })
+      .finally(() => {
+        settled = true;
+      });
+    const rejected = expect(operation).rejects.toMatchObject({ name: "AbortError" });
+    await started;
+    controller.abort();
+    expect(settled).toBe(false);
+    release();
+    await rejected;
+    expect(cdp.calls.mock.calls.some(([, method]) => method === "DOM.resolveNode")).toBe(false);
+  });
+
   it("rejects owner mismatches and invalid numeric bounds", () => {
     const input = snapshotViewportRect(
       [30, 50, 120, 40],
       { target, frameId: "main" },
-      { x: 10, y: 20 },
+      { layoutUnitsPerCssPixel: 1, scrollCss: { x: 10, y: 20 } },
     )!;
     const projection = {
       source: { target, frameId: "main" },
@@ -104,8 +262,20 @@ describe("measurement geometry context", () => {
         source: { target: { tabId: 5 }, frameId: "main" },
       }),
     ).toBeNull();
-    expect(snapshotViewportRect([0, 0, NaN, 40], { target }, { x: 0, y: 0 })).toBeNull();
-    expect(snapshotViewportRect([0, 0, 10, 40], { target }, { x: Infinity, y: 0 })).toBeNull();
+    expect(
+      snapshotViewportRect(
+        [0, 0, NaN, 40],
+        { target },
+        { layoutUnitsPerCssPixel: 1, scrollCss: { x: 0, y: 0 } },
+      ),
+    ).toBeNull();
+    expect(
+      snapshotViewportRect(
+        [0, 0, 10, 40],
+        { target },
+        { layoutUnitsPerCssPixel: 1, scrollCss: { x: Infinity, y: 0 } },
+      ),
+    ).toBeNull();
   });
 
   it("does not turn a border quad or a failed owner read into a content projection", async () => {
@@ -138,7 +308,7 @@ describe("measurement geometry context", () => {
     const input = snapshotViewportRect(
       [0, 0, 300, 200],
       { target, frameId: "nested" },
-      { x: 0, y: 0 },
+      { layoutUnitsPerCssPixel: 1, scrollCss: { x: 0, y: 0 } },
     );
     expect(projectSnapshotRect(input!, projection.projection)).toEqual({
       x: 60,
@@ -188,7 +358,11 @@ describe("measurement geometry context", () => {
       peak = Math.max(peak, active);
       await new Promise<void>((resolve) => release.push(resolve));
       active--;
-      return { cssLayoutViewport: { clientWidth: 100, clientHeight: 100 } };
+      return {
+        visualViewport: { clientWidth: 1000 },
+        cssVisualViewport: { clientWidth: 1000 },
+        cssLayoutViewport: { clientWidth: 100, clientHeight: 100 },
+      };
     });
     const controller = new AbortController();
     const context = new GeometryContext(

apps/extension/src/tools/__tests__/human-loop.test.ts

@@ -433,6 +433,7 @@ describe("handleRequestHelp", () => {
       if (method === "DOM.getContentQuads") {
         return { quads: [[10, 20, 110, 20, 110, 60, 10, 60]] };
       }
+      if (method === "Runtime.evaluate") return { result: { value: { width: 200, height: 100 } } };
       if (method === "Page.getLayoutMetrics") {
         return { cssLayoutViewport: { clientWidth: 200, clientHeight: 100 } };
       }

apps/extension/src/tools/__tests__/interaction.test.ts

@@ -201,6 +201,7 @@ describe("handleClick", () => {
       if (method === "DOM.getContentQuads") {
         return { quads: [[10, 20, 110, 20, 110, 60, 10, 60]] };
       }
+      if (method === "Runtime.evaluate") return { result: { value: { width: 200, height: 100 } } };
       if (method === "Page.getLayoutMetrics") {
         return { cssLayoutViewport: { clientWidth: 200, clientHeight: 100 } };
       }
@@ -220,6 +221,7 @@ describe("handleClick", () => {
       { sessionId: "child-session", method: "DOM.scrollIntoViewIfNeeded" },
       { sessionId: "child-session", method: "DOM.getContentQuads" },
       { sessionId: "child-session", method: "Page.getLayoutMetrics" },
+      { sessionId: "child-session", method: "Runtime.evaluate" },
     ]);
     expect(fake.sent.filter((call) => call.method === "Input.dispatchMouseEvent")).toHaveLength(3);
   });

apps/extension/src/tools/__tests__/observation.test.ts

@@ -93,7 +93,11 @@ function makeFakeCdp(handlers: Record<string, (params?: object) => unknown>) {
     sent.push({ method, params });
     const handler = handlers[method];
     if (!handler && method === "Page.getLayoutMetrics") {
-      return { cssLayoutViewport: { clientWidth: 1280, clientHeight: 720 } };
+      return {
+        visualViewport: { clientWidth: 1000 },
+        cssVisualViewport: { clientWidth: 1000 },
+        cssLayoutViewport: { clientWidth: 1280, clientHeight: 720 },
+      };
     }
     if (!handler) throw new Error(`unexpected CDP call ${method}`);
     return handler(params);
@@ -681,6 +685,59 @@ describe("buildFrameVomScene", () => {
     expect(nestedInput?.parentId).toBe(result.nodes.find((item) => item.backendNodeId === 210)?.id);
   });
 
+  it("excludes an overlay only in its owning document when target backend ids collide", () => {
+    const owner = (id: number): CapturedNode => ({
+      backendNodeId: id,
+      parentBackendNodeId: null,
+      frameId: "main",
+      tag: "iframe",
+      attrs: {},
+      rect: { x: id * 10, y: 0, w: 200, h: 100 },
+      paintOrder: 0,
+      position: "static",
+      pointerEvents: "auto",
+    });
+    const owners = [owner(10), owner(20)];
+    const result = buildFrameVomScene(
+      [
+        {
+          frameId: "main",
+          contextScopeId: "main",
+          target: { tabId: 7 },
+          domNodes: owners,
+          axNodes: [],
+        },
+        ...["left", "right"].map((frameId, i) => ({
+          frameId,
+          contextScopeId: frameId,
+          parentFrameId: "main",
+          ownerBackendNodeId: owners[i].backendNodeId,
+          target: { tabId: 7, sessionId: frameId },
+          excludedBackendNodeIds: new Set(i === 0 ? [7] : []),
+          domNodes: [],
+          axNodes: [
+            {
+              nodeId: "button",
+              frameId,
+              backendDOMNodeId: 7,
+              role: { type: "role", value: "button" },
+              name: { type: "computedString", value: frameId + " action" },
+            },
+          ],
+        })),
+      ],
+      {
+        nodes: owners,
+        viewport: { width: 800, height: 600 },
+        excludedBackendNodeIds: new Set(),
+      },
+    );
+    const rendered = renderVom(result);
+    expect(rendered.text).not.toContain("left action");
+    expect(rendered.text).toContain("right action");
+    expect(rendered.refs.find((ref) => ref.backendNodeId === 7)?.frameId).toBe("right");
+  });
+
   it("does not place a child document at the page root when its frame boundary is unresolved", () => {
     const childNode: CapturedNode = {
       backendNodeId: 101,
@@ -2530,7 +2587,11 @@ describe("handleSnapshot", () => {
       if (method === "Accessibility.enable") return {};
       if (method === "Accessibility.getFullAXTree") return { nodes };
       if (method === "Page.getLayoutMetrics") {
-        return { cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 } };
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
+        };
       }
       if (method === "DOMSnapshot.enable") return {};
       if (method === "DOMSnapshot.captureSnapshot") throw new Error("snapshot unsupported");
@@ -2617,7 +2678,11 @@ describe("handleSnapshot", () => {
       if (method === "Accessibility.enable") return {};
       if (method === "Accessibility.getFullAXTree") return { nodes: [root, button] };
       if (method === "Page.getLayoutMetrics") {
-        return { cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 } };
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
+        };
       }
       if (method === "DOMSnapshot.enable") return {};
       if (method === "DOMSnapshot.captureSnapshot") {
@@ -2625,6 +2690,8 @@ describe("handleSnapshot", () => {
           strings,
           documents: [
             {
+              scrollOffsetX: 0,
+              scrollOffsetY: 0,
               frameId: "root",
               nodes: {
                 parentIndex: [-1, 0],
@@ -2709,7 +2776,11 @@ describe("handleSnapshot", () => {
       if (method === "Accessibility.enable") return {};
       if (method === "Accessibility.getFullAXTree") return { nodes: [root, button] };
       if (method === "Page.getLayoutMetrics") {
-        return { cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 } };
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
+        };
       }
       if (method === "DOMSnapshot.enable") return {};
       if (method === "DOMSnapshot.captureSnapshot") {
@@ -2717,6 +2788,8 @@ describe("handleSnapshot", () => {
           strings,
           documents: [
             {
+              scrollOffsetX: 0,
+              scrollOffsetY: 0,
               frameId: "root",
               nodes: {
                 parentIndex: [-1, 0],
@@ -2804,7 +2877,11 @@ describe("handleSnapshot", () => {
       if (method === "Accessibility.enable") return {};
       if (method === "Accessibility.getFullAXTree") return { nodes: [root, button] };
       if (method === "Page.getLayoutMetrics") {
-        return { cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 } };
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
+        };
       }
       if (method === "DOMSnapshot.enable") return {};
       if (method === "DOMSnapshot.captureSnapshot") {
@@ -2812,6 +2889,8 @@ describe("handleSnapshot", () => {
           strings,
           documents: [
             {
+              scrollOffsetX: 0,
+              scrollOffsetY: 0,
               frameId: "root",
               nodes: {
                 parentIndex: [-1, 0],
@@ -2970,7 +3049,11 @@ describe("handleSnapshot", () => {
         };
       }
       if (method === "Page.getLayoutMetrics") {
-        return { cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 } };
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 },
+        };
       }
       if (method === "DOMSnapshot.enable") return {};
       if (method === "DOMSnapshot.captureSnapshot") {
@@ -3077,6 +3160,8 @@ describe("handleSnapshot", () => {
       strings: S,
       documents: [
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1, 2],
@@ -3135,6 +3220,8 @@ describe("handleSnapshot", () => {
       strings: S,
       documents: [
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1, 1, 1, 1],
@@ -3185,6 +3272,8 @@ describe("handleSnapshot", () => {
   }
 
   const VP_METRICS = {
+    visualViewport: { clientWidth: 1000 },
+    cssVisualViewport: { clientWidth: 1000 },
     cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
   };
 
@@ -3198,6 +3287,8 @@ describe("handleSnapshot", () => {
       strings,
       documents: [
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "main",
           nodes: {
             parentIndex: [-1, 0, 1],
@@ -3218,6 +3309,8 @@ describe("handleSnapshot", () => {
           },
         },
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "child",
           nodes: {
             parentIndex: [-1, 0, 1],
@@ -3287,8 +3380,13 @@ describe("handleSnapshot", () => {
       throw new Error(`unexpected root CDP method ${method}`);
     });
     const sendToTarget = vi.fn(async (_target, method: string) => {
+      if (method === "Runtime.evaluate") return { result: { value: { width: 400, height: 300 } } };
       if (method === "Page.getLayoutMetrics" && ownerGeometry !== "unavailable")
-        return { cssLayoutViewport: { clientWidth: 400, clientHeight: 300 } };
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 400, clientHeight: 300 },
+        };
       if (method === "Accessibility.enable" || method === "DOMSnapshot.enable") return {};
       if (method === "DOMSnapshot.captureSnapshot")
         return { ...snapshot, documents: [snapshot.documents[1]] };
@@ -3331,6 +3429,8 @@ describe("handleSnapshot", () => {
       strings: ["body", "a", "href", "//outside.test/docs", "https://page.test/start"],
       documents: [
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "main",
           ...(hasSnapshotUrl ? { documentURL: 4 } : {}),
           nodes: {
@@ -3452,6 +3552,8 @@ describe("handleSnapshot", () => {
       strings,
       documents: [
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1, 1, 3],
@@ -3594,20 +3696,74 @@ describe("handleSnapshot", () => {
     const result = await captureVomObservation(makeFrameAwareDeps().cdp, 4, "https://example.com", {
       maxTokens,
     });
-    expect(result.text.match(/@warning/g)).toHaveLength(1);
-    expect(result.text).toContain("iframe geometry incomplete");
+    expect(result.text.match(/@warning/g)).toHaveLength(2);
+    expect(result.text).toContain("document identity unverified");
+    expect(result.text).toContain("geometry incomplete");
     expect(result.text.startsWith("@vom 1\n")).toBe(true);
     if (maxTokens === undefined) {
       expect(result.truncated).toBe(false);
       expect(result.text).toContain("Frame action");
       expect(result.matchNodes.find((node) => node.backendNodeId === 22)).toMatchObject({
         rect: null,
-        localRect: { x: 20, y: 30, w: 120, h: 40 },
+        localRect: null,
       });
     }
     if (maxTokens === 100) expect(Math.ceil(result.text.length / 4)).toBeLessThanOrEqual(maxTokens);
   });
 
+  it.each([
+    ["DOMSnapshot.captureSnapshot", "dom"],
+    ["Accessibility.getFullAXTree", "ax"],
+  ])("reports partial capture when child %s fails", async (failedMethod, stage) => {
+    const { cdp } = makeFrameAwareDeps("available");
+    const send = cdp.sendToTarget;
+    cdp.sendToTarget = async (target, method, params) => {
+      if (method === failedMethod) throw new Error("unavailable child data");
+      return send(target, method, params);
+    };
+    for (const maxTokens of [undefined, 100, 0]) {
+      const result = await captureVomObservation(cdp, 4, "https://example.com", { maxTokens });
+      expect(result.text).toContain(`@warning observation incomplete: some ${stage} data`);
+      expect(result.text.match(/@warning/g)).toHaveLength(2);
+      expect(result.text).toContain("document identity unverified");
+      expect(result.text.startsWith("@vom 1\n")).toBe(true);
+      if (maxTokens === undefined) {
+        expect(result.frames.map((frame) => frame.frameId)).toEqual(["main", "child"]);
+        expect(result.truncated).toBe(false);
+      }
+      if (maxTokens === 100)
+        expect(Math.ceil(result.text.length / 4)).toBeLessThanOrEqual(maxTokens);
+    }
+  });
+
+  it("reports omitted child ownership without exposing capture internals", async () => {
+    const { cdp } = makeFrameAwareDeps("available");
+    const send = cdp.send;
+    cdp.send = async (tabId, method, params) => {
+      const result = await send(tabId, method, params);
+      if (method === "DOMSnapshot.captureSnapshot") {
+        const child = await cdp.sendToTarget({ tabId, sessionId: "child-session" }, method, params);
+        (result as { documents: unknown[] }).documents.push(
+          ...(child as { documents: unknown[] }).documents,
+        );
+      }
+      return result as never;
+    };
+    const result = await captureVomObservation(cdp, 4, "https://example.com");
+    expect(result.frames.map((frame) => frame.frameId)).toEqual(["main"]);
+    expect(result.text).toContain("observation incomplete: some ownership data");
+    expect(result.text).not.toContain("Frame action");
+    expect(result).not.toHaveProperty("issues");
+  });
+
+  it("reports unavailable form state while retaining the observed document", async () => {
+    const { cdp } = makeOverlayDeps([], loginSnapshotReply(), VP_METRICS);
+    const result = await captureVomObservation(cdp, 4, "https://example.com");
+    expect(result.text).toContain("observation incomplete: some forms data");
+    expect(result.frames).toHaveLength(1);
+    expect(result.text).not.toContain("unexpected CDP method");
+  });
+
   it.each([
     "available",
     "clipped",
@@ -3617,7 +3773,8 @@ describe("handleSnapshot", () => {
       4,
       "https://example.com",
     );
-    expect(result.text).not.toContain("@warning");
+    expect(result.text).not.toContain("iframe geometry incomplete");
+    expect(result.text).toContain("document identity unverified");
     const node = result.matchNodes.find((item) => item.backendNodeId === 22);
     if (ownerGeometry === "clipped") expect(node?.rect).toBeNull();
     else expect(node?.rect).toEqual({ x: 120, y: 130, w: 120, h: 40 });
@@ -3639,7 +3796,7 @@ describe("handleSnapshot", () => {
     expect(result.matchNodes.find((node) => node.backendNodeId === 22)).toMatchObject({
       frameId: "child",
       tag: "button",
-      localRect: { x: 20, y: 30, w: 120, h: 40 },
+      localRect: null,
     });
     expect(result.refs.find((ref) => ref.backendNodeId === 22)).toMatchObject({
       frameId: "child",
@@ -3983,6 +4140,8 @@ describe("handleSnapshot", () => {
       strings: S,
       documents: [
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1, 0, 3, 4, 5],

apps/extension/src/tools/__tests__/snapshot-coordinates.browser.test.ts

@@ -0,0 +1,355 @@
+// @vitest-environment node
+import { describe, expect, it } from "vitest";
+import type { CdpFrame, CdpFrameGraph, CdpTarget } from "@/browser-driver/frame-graph";
+import { resolveNodeGeometry } from "../frame-geometry";
+import type { CdpRunner } from "../shared";
+import { captureObservationFacts } from "../vom/capture-coordinator";
+
+type Send = <T = Record<string, unknown>>(
+  method: string,
+  params?: object,
+  sessionId?: string,
+) => Promise<T>;
+type Tree = { frame: { id: string; parentId?: string; name?: string }; childFrames?: Tree[] };
+type Rect = { x: number; y: number; w: number; h: number };
+type Oracle = {
+  probes: Record<string, Rect>;
+  viewport: { width: number; height: number };
+  owners: Record<string, { x: number; y: number; scale: number }>;
+};
+
+function clip(rect: Rect, viewport: Oracle["viewport"]): Rect | null {
+  const x = Math.max(0, rect.x),
+    y = Math.max(0, rect.y);
+  const right = Math.min(viewport.width, rect.x + rect.w);
+  const bottom = Math.min(viewport.height, rect.y + rect.h);
+  return right > x && bottom > y ? { x, y, w: right - x, h: bottom - y } : null;
+}
+
+// The independent oracle uses DOM border boxes and this fixture's axis-aligned
+// iframe transforms. No production snapshot conversion/projection builds expectations.
+const oracleExpression = `(() => {
+  const probes = {};
+  for (const node of document.querySelectorAll('[data-geometry-probe]')) {
+    const box = node.getBoundingClientRect();
+    probes[node.id] = { x: box.x, y: box.y, w: box.width, h: box.height };
+  }
+  const owners = {};
+  for (const frame of document.querySelectorAll('iframe')) {
+    const rect = frame.getBoundingClientRect();
+    const style = getComputedStyle(frame);
+    const scale = rect.width / frame.offsetWidth;
+    owners[frame.name] = {
+      x: rect.x + (frame.clientLeft + parseFloat(style.paddingLeft)) * scale,
+      y: rect.y + (frame.clientTop + parseFloat(style.paddingTop)) * scale,
+      scale,
+    };
+  }
+  return { probes, viewport: { width: document.documentElement.clientWidth, height: document.documentElement.clientHeight }, owners };
+})()`;
+
+describe.skipIf(!process.env.BSK_GEOMETRY_CHROME)("real DOMSnapshot coordinate contract", () => {
+  it.each(
+    [
+      { deviceScale: 1, zoom: 1 },
+      { deviceScale: 0.8, zoom: 1 },
+      { deviceScale: 1, zoom: 1.25 },
+      { deviceScale: 2, zoom: 1 },
+      { deviceScale: 2, zoom: 0.8 },
+    ]
+      .flatMap((configuration) => [
+        { ...configuration, fixture: "snapshot-coordinates", scrollbars: "none" },
+        { ...configuration, fixture: "oopif-scrollbars", scrollbars: "both" },
+      ])
+      .concat(
+        ["vertical", "horizontal", "none"].map((scrollbars) => ({
+          deviceScale: 1,
+          zoom: 1,
+          fixture: "oopif-scrollbars",
+          scrollbars,
+        })),
+      ),
+  )("$fixture: device scale $deviceScale, zoom $zoom, scrollbars $scrollbars", async (configuration) => {
+    const evalRoot = new URL("../../../../../evals/browser/", import.meta.url);
+    const { createEvalServer } = await import(new URL("lib/server.mjs", evalRoot).href);
+    const { withChrome } = await import(
+      new URL("cases/regression/snapshot-coordinates/chrome.mjs", evalRoot).href
+    );
+    const server = createEvalServer();
+    const { baseUrl } = await server.start();
+    try {
+      await withChrome(
+        { executable: process.env.BSK_GEOMETRY_CHROME, ...configuration },
+        async (send: Send) => {
+          const { targetId } = await send<{ targetId: string }>("Target.createTarget", {
+            url: "about:blank",
+          });
+          const { sessionId: rootSession } = await send<{ sessionId: string }>(
+            "Target.attachToTarget",
+            { targetId, flatten: true },
+          );
+          await send(
+            "Page.navigate",
+            {
+              url: `${baseUrl}/${configuration.fixture}?run=coordinates&scrollbars=${configuration.scrollbars}`,
+            },
+            rootSession,
+          );
+          await expect
+            .poll(
+              () =>
+                server
+                  .snapshot("coordinates")
+                  .events.some(
+                    (event: { type: string; data: { root?: boolean } }) =>
+                      event.type === "geometry.ready" && event.data.root,
+                  ),
+              { timeout: 10_000 },
+            )
+            .toBe(true);
+
+          const targets = await send<{ targetInfos: { targetId: string; type: string }[] }>(
+            "Target.getTargets",
+          );
+          const sessions = [rootSession];
+          for (const target of targets.targetInfos.filter((target) => target.type === "iframe")) {
+            const { sessionId } = await send<{ sessionId: string }>("Target.attachToTarget", {
+              targetId: target.targetId,
+              flatten: true,
+            });
+            sessions.push(sessionId);
+          }
+          expect(sessions.length).toBe(configuration.fixture === "oopif-scrollbars" ? 3 : 2);
+          const frames: CdpFrame[] = [];
+          const names = new Map<string, string>();
+          const sessionFor = (target: CdpTarget) => target.sessionId ?? rootSession;
+          for (const sessionId of sessions) {
+            const { frameTree } = await send<{ frameTree: Tree }>(
+              "Page.getFrameTree",
+              {},
+              sessionId,
+            );
+            const target: CdpTarget = {
+              tabId: 1,
+              ...(sessionId === rootSession ? {} : { sessionId }),
+            };
+            const visit = (tree: Tree, parentFrameId = tree.frame.parentId) => {
+              frames.push({ frameId: tree.frame.id, parentFrameId, target });
+              names.set(tree.frame.id, tree.frame.name ?? "");
+              for (const child of tree.childFrames ?? []) visit(child, tree.frame.id);
+            };
+            visit(frameTree);
+          }
+          expect(frames).toHaveLength(configuration.fixture === "oopif-scrollbars" ? 3 : 5);
+          for (const frame of frames) {
+            if (!frame.parentFrameId) continue;
+            const parent = frames.find((item) => item.frameId === frame.parentFrameId)!;
+            const owner = await send<{ backendNodeId: number }>(
+              "DOM.getFrameOwner",
+              { frameId: frame.frameId },
+              sessionFor(parent.target),
+            );
+            frame.ownerBackendNodeId = owner.backendNodeId;
+          }
+          const graph: CdpFrameGraph = { rootFrameId: frames[0].frameId, frames };
+          const calls: string[] = [];
+          const cdp: CdpRunner = {
+            send: (tabId, method, params) => {
+              calls.push(`${tabId}:${method}`);
+              return send(method, params, rootSession);
+            },
+            sendToTarget: (target, method, params) => {
+              calls.push(`${target.sessionId ?? target.tabId}:${method}`);
+              if (
+                method === "Runtime.evaluate" &&
+                (params as { expression?: string })?.expression?.includes("window.innerWidth")
+              )
+                calls.push(`${target.sessionId ?? target.tabId}:viewport-size`);
+              return send(method, params, sessionFor(target));
+            },
+            getFrameGraph: async () => graph,
+            getAttachmentId: () => rootSession,
+          };
+          const oracles = new Map<string, Oracle>();
+          for (const frame of frames) {
+            const session = sessionFor(frame.target);
+            const { executionContextId } = await send<{ executionContextId: number }>(
+              "Page.createIsolatedWorld",
+              { frameId: frame.frameId, worldName: "coordinate-oracle" },
+              session,
+            );
+            await expect
+              .poll(
+                async () => {
+                  const ready = await send<{ result: { value: boolean } }>(
+                    "Runtime.evaluate",
+                    {
+                      expression: 'document.documentElement.dataset.geometryReady === "true"',
+                      contextId: executionContextId,
+                      returnByValue: true,
+                    },
+                    session,
+                  );
+                  return ready.result.value;
+                },
+                { timeout: 5_000 },
+              )
+              .toBe(true);
+            // Establish scroll after cross-process target creation/layout settles.
+            const scroll = frame.parentFrameId
+              ? names.get(frame.frameId) === "nested"
+                ? [10, 20]
+                : [40, 100]
+              : [80, 240];
+            await send(
+              "Runtime.evaluate",
+              {
+                expression: `(async () => { scrollTo(${scroll.join(",")}); await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve))); })()`,
+                contextId: executionContextId,
+                awaitPromise: true,
+              },
+              session,
+            );
+            const reply = await send<{ result: { value: Oracle } }>(
+              "Runtime.evaluate",
+              { expression: oracleExpression, contextId: executionContextId, returnByValue: true },
+              session,
+            );
+            oracles.set(frame.frameId, reply.result.value);
+          }
+          const childViewport = await send<{
+            result: {
+              value: { width: number; height: number; clientWidth: number; clientHeight: number };
+            };
+          }>(
+            "Runtime.evaluate",
+            {
+              expression:
+                "({ width: innerWidth, height: innerHeight, clientWidth: document.documentElement.clientWidth, clientHeight: document.documentElement.clientHeight })",
+              returnByValue: true,
+            },
+            sessions[1],
+          );
+          for (const dimension of ["Width", "Height"] as const) {
+            const occupied =
+              childViewport.result.value[dimension === "Width" ? "width" : "height"] -
+              childViewport.result.value[`client${dimension}`];
+            if (
+              configuration.scrollbars === "both" ||
+              configuration.scrollbars === (dimension === "Width" ? "vertical" : "horizontal")
+            )
+              expect(occupied).toBeGreaterThan(0);
+            else expect(occupied).toBe(0);
+          }
+          const facts = await captureObservationFacts(cdp, 1);
+          expect(facts.issues).toEqual([]);
+          expect(calls.filter((call) => call.endsWith(":Page.getLayoutMetrics"))).toHaveLength(
+            sessions.length,
+          );
+          // Identity verification also uses Runtime.evaluate; count the full viewport reads separately.
+          const viewportReadsBeforeLive = calls.filter((call) => call.endsWith(":viewport-size"));
+          expect(new Set(viewportReadsBeforeLive).size).toBe(viewportReadsBeforeLive.length);
+          expect(viewportReadsBeforeLive.length).toBeLessThanOrEqual(sessions.length - 1);
+          for (const frame of frames) {
+            for (const [id, local] of Object.entries(oracles.get(frame.frameId)!.probes)) {
+              const node = facts.documents
+                .find((doc) => doc.frame.frameId === frame.frameId)
+                ?.domNodes.find((node) => node.attrs.id === id);
+              expect(node, `missing ${id} in ${names.get(frame.frameId) || "root"}`).toBeDefined();
+              let top = clip(local, oracles.get(frame.frameId)!.viewport);
+              let current = frame;
+              while (top && current.parentFrameId) {
+                const parentOracle = oracles.get(current.parentFrameId)!;
+                const owner = parentOracle.owners[names.get(current.frameId)!];
+                top = clip(
+                  {
+                    x: owner.x + top.x * owner.scale,
+                    y: owner.y + top.y * owner.scale,
+                    w: top.w * owner.scale,
+                    h: top.h * owner.scale,
+                  },
+                  parentOracle.viewport,
+                );
+                current = frames.find((item) => item.frameId === current.parentFrameId)!;
+              }
+              for (const key of ["x", "y", "w", "h"] as const)
+                expect(
+                  Math.abs(node!.localRect![key] - local[key]),
+                  `${names.get(frame.frameId)} ${id} local ${key}`,
+                ).toBeLessThan(2);
+              if (!top) {
+                expect(node!.rect, `${id} must be clipped out`).toBeNull();
+                if (configuration.fixture === "oopif-scrollbars")
+                  expect(
+                    await resolveNodeGeometry(cdp, 1, {
+                      target: frame.target,
+                      frameId: frame.frameId,
+                      backendNodeId: node!.backendNodeId,
+                    }),
+                  ).toMatchObject({ code: "permission_denied" });
+                continue;
+              }
+              expect(node!.rect).not.toBeNull();
+              for (const key of ["x", "y", "w", "h"] as const)
+                expect(
+                  Math.abs(node!.rect![key] - top[key]),
+                  `${names.get(frame.frameId)} ${id} top ${key}`,
+                ).toBeLessThan(2);
+              if (configuration.fixture !== "oopif-scrollbars") continue;
+              const live = await resolveNodeGeometry(cdp, 1, {
+                target: frame.target,
+                frameId: frame.frameId,
+                backendNodeId: node!.backendNodeId,
+              });
+              if ("code" in live) throw new Error(live.message);
+              for (const [key, liveKey] of [
+                ["x", "x"],
+                ["y", "y"],
+                ["w", "width"],
+                ["h", "height"],
+              ] as const)
+                expect(
+                  Math.abs(live.topBounds[liveKey] - top[key]),
+                  `${id} live ${key}`,
+                ).toBeLessThan(2);
+              const before = server.snapshot("coordinates").events.length;
+              for (const type of ["mousePressed", "mouseReleased"])
+                await send(
+                  "Input.dispatchMouseEvent",
+                  { type, ...live.actionPoint, button: "left", clickCount: 1 },
+                  rootSession,
+                );
+              await expect
+                .poll(
+                  () =>
+                    server
+                      .snapshot("coordinates")
+                      .events.slice(before)
+                      .some(
+                        (event: { type: string; path: string; data: { probe?: string } }) =>
+                          event.type === "geometry.clicked" &&
+                          event.data.probe === id &&
+                          event.path ===
+                            (frame.parentFrameId
+                              ? names.get(frame.frameId) === "nested"
+                                ? "/oopif-scrollbars/nested"
+                                : "/oopif-scrollbars/frame"
+                              : "/oopif-scrollbars"),
+                      ),
+                  { timeout: 3000 },
+                )
+                .toBe(true);
+            }
+          }
+          const metrics = await send<{
+            cssVisualViewport: { zoom: number };
+            visualViewport: { clientWidth: number };
+          }>("Page.getLayoutMetrics", {}, rootSession);
+          expect(metrics.cssVisualViewport.zoom).toBeCloseTo(configuration.zoom, 4);
+        },
+      );
+    } finally {
+      await server.stop();
+    }
+  }, 30_000);
+});

apps/extension/src/tools/frame-geometry.ts

@@ -161,7 +161,8 @@ export async function resolveNodeGeometry(
         return geometryError(`could not resolve frame geometry for ${address.frameId}`);
       topVisibleRegions = projectRegionToViewport(localRegion, projection);
       if (address.target.sessionId) {
-        const localViewport = projection.edges[0]?.sourceViewport ?? projection.topViewport;
+        const localViewport = await context.viewport(address.target);
+        if (!localViewport) return geometryError("could not resolve target viewport geometry");
         const localVisibleRegions = localRegion
           .map((polygon) =>
             clipPolygon(

apps/extension/src/tools/geometry/coordinate-types.ts

@@ -25,6 +25,12 @@ export interface UnavailableFrameProjection {
   ownerBackendNodeId: number;
 }
 
+export interface UnavailableSnapshotCoordinates {
+  status: "unavailable";
+  source: CoordinateOwner;
+  reason: "snapshot-coordinates-unavailable";
+}
+
 export type SnapshotProjectionResult =
   | { status: "available"; projection: SnapshotProjection }
   | UnavailableFrameProjection;
@@ -32,25 +38,74 @@ export type SnapshotProjectionResult =
 /** Descendants inherit the failed boundary without attempting another owner read. */
 export type FrameProjectionIssue =
   | UnavailableFrameProjection
-  | { status: "blocked"; source: CoordinateOwner; cause: UnavailableFrameProjection };
+  | UnavailableSnapshotCoordinates
+  | {
+      status: "blocked";
+      source: CoordinateOwner;
+      cause: UnavailableFrameProjection | UnavailableSnapshotCoordinates;
+    };
 
 export type FrameProjectionState = SnapshotProjectionResult | FrameProjectionIssue;
 
-/** DOMSnapshot bounds are document-relative CSS pixels, independent of raster DPR. */
+export interface SnapshotCoordinates {
+  layoutUnitsPerCssPixel: number;
+  scrollCss: { x: number; y: number };
+}
+
+/** Snapshot scroll offsets share the raw layout units of its bounds. Only a
+ * target's root document may fall back to that target's CSS layout viewport. */
+export function snapshotCoordinates(
+  document: { scrollOffsetX?: number; scrollOffsetY?: number },
+  layoutUnitsPerCssPixel: number | null,
+  rootScrollCss?: { x?: number; y?: number },
+): SnapshotCoordinates | null {
+  if (
+    layoutUnitsPerCssPixel === null ||
+    !Number.isFinite(layoutUnitsPerCssPixel) ||
+    layoutUnitsPerCssPixel <= 0
+  )
+    return null;
+  const x =
+    document.scrollOffsetX === undefined
+      ? rootScrollCss?.x
+      : document.scrollOffsetX / layoutUnitsPerCssPixel;
+  const y =
+    document.scrollOffsetY === undefined
+      ? rootScrollCss?.y
+      : document.scrollOffsetY / layoutUnitsPerCssPixel;
+  if (x === undefined || y === undefined || !Number.isFinite(x) || !Number.isFinite(y)) return null;
+  return { layoutUnitsPerCssPixel, scrollCss: { x, y } };
+}
+
+/** Convert raw document-relative Blink layout units exactly once, before any
+ * CSS viewport clipping or frame projection. This scale is not screenshot zoom. */
 export function snapshotViewportRect(
   bounds: number[],
   owner: CoordinateOwner,
-  scroll: { x: number; y: number },
+  coordinates: SnapshotCoordinates | null,
 ): FrameViewportRect | null {
-  if (bounds.length < 4 || !bounds.slice(0, 4).every(Number.isFinite)) return null;
+  if (!coordinates || bounds.length < 4 || !bounds.slice(0, 4).every(Number.isFinite)) return null;
+  const { layoutUnitsPerCssPixel: scale, scrollCss: scroll } = coordinates;
   const [x, y, width, height] = bounds;
-  if (width <= 0 || height <= 0 || !Number.isFinite(scroll.x) || !Number.isFinite(scroll.y)) {
+  if (
+    !Number.isFinite(scale) ||
+    scale <= 0 ||
+    width <= 0 ||
+    height <= 0 ||
+    !Number.isFinite(scroll.x) ||
+    !Number.isFinite(scroll.y)
+  ) {
     return null;
   }
   return {
     space: "frame-viewport-css",
     owner,
-    rect: { x: x - scroll.x, y: y - scroll.y, width, height },
+    rect: {
+      x: x / scale - scroll.x,
+      y: y / scale - scroll.y,
+      width: width / scale,
+      height: height / scale,
+    },
   };
 }
 

apps/extension/src/tools/geometry/frame-context.ts

@@ -9,15 +9,19 @@ import {
   type Polygon,
   type ProjectiveEdge,
   parseCdpQuad,
+  projectPolygon,
   type Quad,
   type Size,
+  viewportPolygon,
 } from "../geometry";
 import { type CdpRunner, sendToCdpTarget } from "../shared";
 import type { CoordinateOwner, CssViewport, SnapshotProjectionResult } from "./coordinate-types";
 
+import { readSnapshotOwnerSizes } from "./snapshot-owner-sizes";
+
 export interface LayoutMetrics {
-  cssVisualViewport?: { zoom?: number };
-  visualViewport?: { zoom?: number };
+  cssVisualViewport?: { zoom?: number; clientWidth?: number; clientHeight?: number };
+  visualViewport?: { zoom?: number; clientWidth?: number; clientHeight?: number };
   cssLayoutViewport?: {
     clientWidth?: number;
     clientHeight?: number;
@@ -27,6 +31,29 @@ export interface LayoutMetrics {
   layoutViewport?: { clientWidth?: number; clientHeight?: number; pageX?: number; pageY?: number };
 }
 
+/** Chromium emits these paired floating-point dimensions before/after dividing
+ * by LayoutZoomFactor. Integer layout viewport dimensions lose precision at
+ * fractional zoom. Neither visualViewport.scale nor .zoom is this conversion.
+ * See InspectorPageAgent::getLayoutMetrics in Chromium. */
+export function snapshotLayoutScale(metrics: LayoutMetrics): number | null {
+  for (const dimension of ["clientWidth", "clientHeight"] as const) {
+    const raw = metrics.visualViewport?.[dimension];
+    const css = metrics.cssVisualViewport?.[dimension];
+    if (
+      raw !== undefined &&
+      css !== undefined &&
+      Number.isFinite(raw) &&
+      Number.isFinite(css) &&
+      raw > 0 &&
+      css > 0
+    ) {
+      const scale = raw / css;
+      if (Number.isFinite(scale) && scale > 0) return scale;
+    }
+  }
+  return null;
+}
+
 /** The legacy field is a compatibility fallback, never a source of raster DPR. */
 export function cssViewport(metrics: LayoutMetrics): CssViewport {
   const value = metrics.cssLayoutViewport ?? metrics.layoutViewport;
@@ -42,9 +69,11 @@ export function cssViewport(metrics: LayoutMetrics): CssViewport {
 /** One read-only measurement phase. Discard after scrolling or any later operation. */
 export class GeometryContext {
   private readonly metrics = new Map<string, Promise<LayoutMetrics>>();
+  private readonly frameViewports = new Map<string, Promise<Size | null>>();
   private readonly owners = new Map<string, Promise<Quad | null>>();
   private readonly projections = new Map<string, Promise<GeometryProjection | null>>();
   private readonly snapshotOwners = new Map<string, Promise<{ quad: Quad; size: Size } | null>>();
+  private readonly sizeBatches = new Map<string, () => Promise<Map<number, Size>>>();
   private active = 0;
   private readonly waiting: Array<() => void> = [];
   private graphPromise?: Promise<CdpFrameGraph | null>;
@@ -131,6 +160,35 @@ export class GeometryContext {
       : null;
   }
 
+  /** The full OOPIF viewport maps to its owner's content quad. Layout metrics
+   * exclude occupied scrollbars and remain the clipping boundary, not the scale. */
+  private frameViewport(target: CdpTarget): Promise<Size | null> {
+    const key = cdpTargetKey(target);
+    let promise = this.frameViewports.get(key);
+    if (!promise) {
+      promise = this.request<{ result?: { value?: Size }; exceptionDetails?: unknown }>(
+        target,
+        "Runtime.evaluate",
+        {
+          expression: "({ width: window.innerWidth, height: window.innerHeight })",
+          returnByValue: true,
+        },
+      ).then(({ result, exceptionDetails }) => {
+        const size = result?.value;
+        return !exceptionDetails &&
+          size &&
+          Number.isFinite(size.width) &&
+          Number.isFinite(size.height) &&
+          size.width > 0 &&
+          size.height > 0
+          ? size
+          : null;
+      });
+      this.frameViewports.set(key, promise);
+    }
+    return promise;
+  }
+
   ownerContent(target: CdpTarget, backendNodeId: number): Promise<Quad | null> {
     const key = `${cdpTargetKey(target)}:${backendNodeId}`;
     let promise = this.owners.get(key);
@@ -186,12 +244,34 @@ export class GeometryContext {
       : { status: "unavailable", source, ownerBackendNodeId };
   }
 
+  /** Register one target's snapshot owners; the batch starts only when a
+   * projection actually needs a size. Single owners keep the cheaper old path. */
+  registerSnapshotOwners(target: CdpTarget, owners: ReadonlySet<number>): void {
+    const key = cdpTargetKey(target);
+    if (owners.size < 2 || this.sizeBatches.has(key)) return;
+    let pending: Promise<Map<number, Size>> | undefined;
+    this.sizeBatches.set(key, () => {
+      pending ??= readSnapshotOwnerSizes(
+        (method, params, cleanup) => this.request(target, method, params, cleanup),
+        owners,
+      ).catch((error) => {
+        if (error && typeof error === "object" && "name" in error && error.name === "AbortError")
+          throw error;
+        return new Map<number, Size>();
+      });
+      return pending;
+    });
+  }
+
   private async snapshotOwner(
     target: CdpTarget,
     backendNodeId: number,
   ): Promise<{ quad: Quad; size: Size } | null> {
     const quad = await this.ownerContent(target, backendNodeId);
     if (!quad) return null;
+    const batchSize = (await this.sizeBatches.get(cdpTargetKey(target))?.())?.get(backendNodeId);
+    if (this.signal?.aborted) throw new DOMException("geometry aborted", "AbortError");
+    if (batchSize) return { quad, size: batchSize };
     const resolved = await this.request<{ object?: { objectId?: string } }>(
       target,
       "DOM.resolveNode",
@@ -294,12 +374,19 @@ export class GeometryContext {
       const parent = frames.get(root.parentFrameId);
       if (!parent || root.ownerBackendNodeId === undefined) return null;
       const destinationQuad = await this.ownerContent(parent.target, root.ownerBackendNodeId);
-      const source = await this.viewport(root.target);
+      if (!destinationQuad) return null;
+      const source = await this.frameViewport(root.target);
+      const visible = await this.viewport(root.target);
       const parentRoot = this.targetRoot(frames, parent);
-      if (!destinationQuad || !source || !parentRoot) return null;
+      if (!source || !visible || !parentRoot) return null;
       const destinationClips = await this.clips(frames, parent, parentRoot);
       if (!destinationClips) return null;
-      edges.push({ sourceViewport: source, destinationQuad, destinationClips });
+      const edge = { sourceViewport: source, destinationQuad, destinationClips };
+      // Keep scrollbar strips clipped at every target boundary, including
+      // intermediate OOPIFs. Project the clip with the same full-viewport scale.
+      if (source.width !== visible.width || source.height !== visible.height)
+        destinationClips.push(projectPolygon(viewportPolygon(visible), edge));
+      edges.push(edge);
       root = parentRoot;
     }
     const topViewport = await this.viewport(root.target);

apps/extension/src/tools/geometry/snapshot-owner-sizes.ts

@@ -0,0 +1,74 @@
+import type { Size } from "../geometry";
+
+interface SerializedValue {
+  type: string;
+  value?: unknown;
+}
+
+type Send = <T>(method: string, params: object, cleanup?: boolean) => Promise<T>;
+
+/** Batch only accessible frame owners. Missing/shadow/cross-origin owners keep
+ * the existing node-scoped read; no page-wide style columns are requested. */
+export async function readSnapshotOwnerSizes(
+  send: Send,
+  owners: ReadonlySet<number>,
+): Promise<Map<number, Size>> {
+  const sizes = new Map<number, Size>();
+  const objectGroup = `bsk-frame-sizes-${crypto.randomUUID()}`;
+  try {
+    const reply = await send<{ result?: { deepSerializedValue?: SerializedValue } }>(
+      "Runtime.evaluate",
+      {
+        expression: `(() => {
+          const result = [];
+          const documents = [document];
+          for (let i = 0; i < documents.length && result.length < ${owners.size}; i++) {
+            for (const owner of documents[i].querySelectorAll('iframe,frame')) {
+              if (result.length >= ${owners.size}) break;
+              if (!owner.isConnected) continue;
+              const style = getComputedStyle(owner);
+              result.push([owner, JSON.stringify({
+                width: owner.clientWidth - parseFloat(style.paddingLeft) - parseFloat(style.paddingRight),
+                height: owner.clientHeight - parseFloat(style.paddingTop) - parseFloat(style.paddingBottom)
+              })]);
+              try { if (owner.contentDocument) documents.push(owner.contentDocument); } catch {}
+            }
+          }
+          return result;
+        })()`,
+        objectGroup,
+        serializationOptions: {
+          serialization: "deep",
+          maxDepth: 3,
+          additionalParameters: { maxNodeDepth: 0, includeShadowTree: "none" },
+        },
+      },
+    );
+    const result = reply.result?.deepSerializedValue;
+    if (result?.type !== "array" || !Array.isArray(result.value)) return sizes;
+    for (const entry of result.value as SerializedValue[]) {
+      if (entry.type !== "array" || !Array.isArray(entry.value)) continue;
+      const [node, data] = entry.value as SerializedValue[];
+      if (node?.type !== "node" || data?.type !== "string" || typeof data.value !== "string")
+        continue;
+      const id = (node.value as { backendNodeId?: number } | undefined)?.backendNodeId;
+      if (id === undefined || !owners.has(id)) continue;
+      try {
+        const size = JSON.parse(data.value) as Size;
+        if (
+          size &&
+          Number.isFinite(size.width) &&
+          Number.isFinite(size.height) &&
+          size.width > 0 &&
+          size.height > 0
+        )
+          sizes.set(id, size);
+      } catch {
+        /* An invalid entry uses the existing individual read. */
+      }
+    }
+  } finally {
+    await send("Runtime.releaseObjectGroup", { objectGroup }, true).catch(() => {});
+  }
+  return sizes;
+}

apps/extension/src/tools/observation.ts

@@ -926,19 +926,41 @@ export async function captureVomObservation(
   );
   // Reserve space using the renderer's character-based token estimate. Like VOM
   // headers, this integrity notice remains visible even under a tiny token budget.
-  const geometryNotice = facts.issues.some((issue) => issue.stage === "geometry")
-    ? "@warning iframe geometry incomplete: some frame content has no top-level coordinates.\n"
-    : "";
+  const notices: string[] = [];
+  if (facts.issues.some((issue) => issue.stage === "geometry"))
+    notices.push(
+      "@warning geometry incomplete: some page or frame content has no top-level coordinates.",
+    );
+  const incompleteStages = ["dom", "ax", "forms", "ownership"].filter((stage) =>
+    facts.issues.some((issue) => issue.stage === stage),
+  );
+  if (incompleteStages.length)
+    notices.push(
+      `@warning observation incomplete: some ${incompleteStages.join(", ")} data is unavailable or omitted.`,
+    );
+  if (
+    facts.issues.some(
+      (issue) => issue.stage === "identity" && issue.reason !== "identity-unverified",
+    )
+  )
+    notices.push(
+      "@warning observation incomplete: some documents were omitted because their identity changed or could not be revalidated.",
+    );
+  if (facts.issues.some((issue) => issue.reason === "identity-unverified"))
+    notices.push(
+      "@warning document identity unverified: some retained documents could not be checked for changes during capture.",
+    );
+  const captureNotice = notices.join("\n");
   const rendered = renderVom(decoratedScene, {
     maxDepth: options.maxDepth,
     maxTokens:
-      !geometryNotice || options.maxTokens === undefined
+      !captureNotice || options.maxTokens === undefined
         ? options.maxTokens
-        : Math.max(0, options.maxTokens - Math.ceil(geometryNotice.length / 4)),
+        : Math.max(0, options.maxTokens - Math.ceil((captureNotice.length + 1) / 4)),
     redactValues: options.redactValues,
     activeRegionPolicy: options.activeRegionPolicy,
   });
-  if (geometryNotice) rendered.text += `\n${geometryNotice.trimEnd()}`;
+  if (captureNotice) rendered.text += `\n${captureNotice}`;
   throwIfAborted(options.signal, "observation");
   return projectRecordSafeObservation({
     rootFrameId: captured.rootFrameId ?? normalizedDocuments[0]?.frameId ?? "root",

apps/extension/src/tools/shared.ts

@@ -55,6 +55,7 @@ export interface CdpRunner {
   sendToTarget?<T = unknown>(target: CdpTarget, method: string, params?: object): Promise<T>;
   detach?(tabId: number): Promise<void>;
   getFrameGraph?(tabId: number): Promise<CdpFrameGraph>;
+  getAttachmentId?(tabId: number): string | undefined;
   ensureAttachedToUrl?(tabId: number, expectedUrl: string | undefined): Promise<void>;
   trackSessionTab?(sessionId: string, tabId: number): void;
   releaseSessionTab?(sessionId: string, tabId: number): Promise<void>;

apps/extension/src/tools/vom/__tests__/capture-coordinator.test.ts

@@ -2,13 +2,22 @@ import { describe, expect, it, vi } from "vitest";
 import type { CdpFrame, CdpTarget } from "@/browser-driver/frame-graph";
 import { cdpTargetKey } from "@/browser-driver/frame-graph";
 import { OVERLAY_HOST_MARKER_ATTR } from "@/lib/overlay-bridge";
+import { captureVomObservation } from "../../observation";
 import type { CdpRunner } from "../../shared";
 import { captureObservationFacts, semanticCapture } from "../capture-coordinator";
 import { buildSemanticGraph } from "../semantic-graph/build";
-import { REQUESTED_STYLES } from "../snapshot";
+import { REQUESTED_STYLES, type SnapshotReply } from "../snapshot";
 
 function fixture(
-  options: { frames?: CdpFrame[]; fail?: string; omitDocument?: string; overlay?: string } = {},
+  options: {
+    frames?: CdpFrame[];
+    after?: Record<string, { element?: number; missing?: boolean; unreadable?: boolean }>;
+    fail?: string;
+    missingIdentity?: boolean;
+    omitDocument?: string;
+    attachmentChanged?: boolean;
+    overlay?: string;
+  } = {},
 ) {
   const frames = options.frames ?? [
     { frameId: "main", target: { tabId: 4 } },
@@ -34,7 +43,10 @@ function fixture(
   const elements = new Map(
     frames.map((frame, i) => [frame.frameId, frame.target.sessionId ? 1 : i * 10 + 1]),
   );
+  const contexts = new Map(frames.map((frame, i) => [i + 1, frame.frameId]));
   const logs: Array<{ target: CdpTarget; method: string; params: Record<string, unknown> }> = [];
+  let snapshots = 0;
+  const targetCount = new Set(frames.map((frame) => cdpTargetKey(frame.target))).size;
   const send = vi.fn(
     async <T>(target: CdpTarget, method: string, params: object = {}): Promise<T> => {
       logs.push({ target, method, params: params as Record<string, unknown> });
@@ -42,9 +54,35 @@ function fixture(
       if (options.fail === `${target.sessionId ?? "main"}:${method}`)
         throw new Error("fixture failure");
       let result: unknown = {};
+      if (method === "Page.createIsolatedWorld")
+        result = {
+          executionContextId: frames.findIndex((frame) => frame.frameId === args.frameId) + 1,
+        };
+      if (method === "Runtime.evaluate" && args.contextId) {
+        const id = contexts.get(Number(args.contextId))!;
+        const change = options.after?.[id];
+        result =
+          options.missingIdentity || change?.unreadable
+            ? {}
+            : {
+                result: {
+                  deepSerializedValue: change?.missing
+                    ? { type: "null" }
+                    : {
+                        type: "node",
+                        value: { backendNodeId: change?.element ?? elements.get(id) },
+                      },
+                },
+              };
+      }
       if (method === "Page.getLayoutMetrics")
-        result = { cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 } };
+        result = {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 },
+        };
       if (method === "DOMSnapshot.captureSnapshot") {
+        snapshots++;
         expect((params as { computedStyles: unknown }).computedStyles).toEqual(REQUESTED_STYLES);
         result = {
           strings: [
@@ -66,14 +104,39 @@ function fixture(
             )
             .map((frame) => {
               const element = elements.get(frame.frameId)!;
+              const localFrames = frames.filter(
+                (f) =>
+                  cdpTargetKey(f.target) === cdpTargetKey(target) &&
+                  f.frameId !== options.omitDocument,
+              );
+              const children = localFrames.filter((f) => f.parentFrameId === frame.frameId);
+
               return {
+                scrollOffsetX: 0,
+                scrollOffsetY: 0,
                 frameId: frame.frameId,
                 nodes: {
-                  backendNodeId: [element - 1, element + 10000, element, element + 1],
-                  nodeName: [0, 1, 1, 2],
-                  nodeType: [9, 10, 1, 1],
-                  parentIndex: [-1, 0, 0, 2],
-                  attributes: [[], [], [], frame.frameId === options.overlay ? [3, 4] : []],
+                  backendNodeId: [
+                    element - 1,
+                    element + 10000,
+                    element,
+                    element + 1,
+                    ...children.map((f) => f.ownerBackendNodeId!),
+                  ],
+                  nodeName: [0, 1, 1, 2, ...children.map(() => 2)],
+                  nodeType: [9, 10, 1, 1, ...children.map(() => 1)],
+                  parentIndex: [-1, 0, 0, 2, ...children.map(() => 2)],
+                  attributes: [
+                    [],
+                    [],
+                    [],
+                    frame.frameId === options.overlay ? [3, 4] : [],
+                    ...children.map(() => []),
+                  ],
+                  contentDocumentIndex: {
+                    index: children.map((_, i) => 4 + i),
+                    value: children.map((f) => localFrames.indexOf(f)),
+                  },
                 },
                 layout: {
                   nodeIndex: [2, 3],
@@ -108,6 +171,12 @@ function fixture(
     },
   );
   const cdp: CdpRunner = {
+    getAttachmentId: () =>
+      options.missingIdentity
+        ? undefined
+        : options.attachmentChanged && snapshots === targetCount
+          ? "new-attachment"
+          : "attachment",
     getFrameGraph: async () => ({ rootFrameId: frames[0].frameId, frames }),
     send: (tabId, method, params) =>
       (send as NonNullable<CdpRunner["sendToTarget"]>)({ tabId }, method, params),
@@ -117,12 +186,44 @@ function fixture(
 }
 
 describe("captureObservationFacts", () => {
+  it("normalizes snapshot-owned root scroll instead of mixing in stale CSS scroll", async () => {
+    const { cdp } = fixture({ frames: [{ frameId: "main", target: { tabId: 4 } }] });
+    const original = cdp.sendToTarget!;
+    cdp.sendToTarget = async (target, method, params) => {
+      if (method === "Page.getLayoutMetrics")
+        return {
+          visualViewport: { clientWidth: 2000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 999, pageY: 999 },
+        } as never;
+      const reply = await original(target, method, params);
+      if (method === "DOMSnapshot.captureSnapshot") {
+        const doc = (reply as SnapshotReply).documents![0];
+        doc.scrollOffsetX = 40;
+        doc.scrollOffsetY = 200;
+        doc.layout!.bounds![1] = [200, 800, 240, 80];
+      }
+      return reply as never;
+    };
+    cdp.send = (tabId, method, params) => cdp.sendToTarget!({ tabId }, method, params);
+    const facts = await captureObservationFacts(cdp, 4);
+    expect(facts.documents[0].domNodes.find((node) => node.backendNodeId === 2)).toMatchObject({
+      localRect: { x: 80, y: 300, w: 120, h: 40 },
+      rect: { x: 80, y: 300, w: 120, h: 40 },
+      rendered: true,
+    });
+    expect(facts.issues).toEqual([]);
+  });
+
   it("collects each target once and scopes equal backend IDs", async () => {
     const { cdp, logs } = fixture();
     const facts = await captureObservationFacts(cdp, 4);
     expect(logs.filter((call) => call.method === "DOMSnapshot.captureSnapshot")).toHaveLength(2);
     expect(logs.filter((call) => call.method === "Accessibility.enable")).toHaveLength(2);
     expect(logs.filter((call) => call.method === "Accessibility.getFullAXTree")).toHaveLength(4);
+    expect(facts.documents.every((doc) => doc.identity)).toBe(true);
+    expect(logs.filter((call) => call.method === "DOM.describeNode")).toHaveLength(0);
+    expect(logs.filter((call) => call.method === "Page.createIsolatedWorld")).toHaveLength(4);
     const main = facts.documents.find((doc) => doc.frame.frameId === "main")!;
     const remote = facts.documents.find((doc) => doc.frame.frameId === "remote")!;
     expect(main.index.nodes.get(2)).not.toBe(remote.index.nodes.get(2));
@@ -133,6 +234,219 @@ describe("captureObservationFacts", () => {
     expect(facts.finishedAt).toBeGreaterThanOrEqual(facts.startedAt);
   });
 
+  it.each([
+    { element: 99 },
+    { missing: true },
+  ])("isolates changed child identity %j and dependent descendants", async (change) => {
+    const { cdp } = fixture({ after: { same: change } });
+    const facts = await captureObservationFacts(cdp, 4);
+    expect(facts.documents.map((doc) => doc.frame.frameId)).toEqual(["main", "remote"]);
+    expect(facts.issues).toContainEqual(
+      expect.objectContaining({ frameId: "same", reason: "document-changed" }),
+    );
+  });
+
+  it.each([
+    { after: { main: { element: 99 } } },
+    { attachmentChanged: true },
+  ])("rejects a root replacement or reattachment %j", async (options) => {
+    await expect(captureObservationFacts(fixture(options).cdp, 4)).rejects.toThrow(
+      "document identity",
+    );
+  });
+
+  it.each([
+    "main",
+    "same",
+  ])("does not publish a previously identified %s document after identity reads fail", async (frameId) => {
+    const { cdp } = fixture({ after: { [frameId]: { unreadable: true } } });
+    if (frameId === "main")
+      await expect(captureObservationFacts(cdp, 4)).rejects.toThrow("document identity");
+    else {
+      const facts = await captureObservationFacts(cdp, 4);
+      expect(facts.documents.map((doc) => doc.frame.frameId)).toEqual(["main", "remote"]);
+      expect(facts.issues).toContainEqual(
+        expect.objectContaining({ frameId, reason: "identity-unavailable" }),
+      );
+    }
+  });
+
+  it("validates newly discovered snapshot documents without a pre-snapshot identity read", async () => {
+    const { cdp, logs } = fixture();
+    const graph = await cdp.getFrameGraph!(4);
+    cdp.getFrameGraph = async () => ({ ...graph, frames: graph.frames.slice(0, 1) });
+    const facts = await captureObservationFacts(cdp, 4);
+    expect(facts.documents.map((doc) => doc.frame.frameId)).toEqual(["main", "same", "nested"]);
+    expect(facts.documents.every((doc) => doc.identity)).toBe(true);
+    expect(logs.filter((call) => call.method === "Page.createIsolatedWorld")).toHaveLength(3);
+    expect(logs.findIndex((call) => call.method === "Page.createIsolatedWorld")).toBeGreaterThan(
+      logs.findIndex((call) => call.method === "Accessibility.getFullAXTree"),
+    );
+  });
+
+  it("rejects a snapshot root that no longer matches the current frame root", async () => {
+    const { cdp } = fixture();
+    const original = cdp.sendToTarget!;
+    cdp.sendToTarget = async (target, method, params) => {
+      const result = await original(target, method, params);
+      if (method === "DOMSnapshot.captureSnapshot" && !target.sessionId) {
+        const snapshot = result as {
+          documents: { frameId: string; nodes: { backendNodeId: number[] } }[];
+        };
+        snapshot.documents[0].nodes.backendNodeId[2] = 999;
+      }
+      return result as never;
+    };
+    cdp.send = (tabId, method, params) => cdp.sendToTarget!({ tabId }, method, params);
+    await expect(captureObservationFacts(cdp, 4)).rejects.toThrow("document identity");
+  });
+
+  it("starts after-identity reads only after every target finishes and propagates cancellation during identity cleanup", async () => {
+    const { cdp, logs } = fixture();
+    const controller = new AbortController();
+    const original = cdp.sendToTarget!;
+    let identityCleanup = 0;
+    cdp.sendToTarget = async (target, method, params) => {
+      if (method === "Page.createIsolatedWorld") {
+        expect(logs.filter((call) => call.method === "Accessibility.getFullAXTree")).toHaveLength(
+          4,
+        );
+      }
+      const result = await original(target, method, params);
+      if (
+        method === "Runtime.releaseObjectGroup" &&
+        String((params as { objectGroup?: string })?.objectGroup).startsWith(
+          "bsk-document-identity-",
+        ) &&
+        target.sessionId === "remote"
+      ) {
+        if (++identityCleanup === 1) controller.abort();
+      }
+      return result as never;
+    };
+    cdp.send = (tabId, method, params) => cdp.sendToTarget!({ tabId }, method, params);
+    await expect(captureObservationFacts(cdp, 4, controller.signal)).rejects.toMatchObject({
+      name: "AbortError",
+    });
+    expect(identityCleanup).toBe(1);
+  });
+
+  it.each([
+    1, 10, 100,
+  ])("bounds identity reads for %i same-target documents after snapshot and AX collection", async (count) => {
+    const frames: CdpFrame[] = Array.from({ length: count }, (_, i) => ({
+      frameId: `frame-${i}`,
+      target: { tabId: 4 },
+      ...(i ? { parentFrameId: "frame-0", ownerBackendNodeId: 90000 + i } : {}),
+    }));
+    const { cdp, logs } = fixture({ frames });
+    const original = cdp.sendToTarget!;
+    let active = 0;
+    let peak = 0;
+    let released = 0;
+    cdp.sendToTarget = async (target, method, params) => {
+      if (method === "Page.createIsolatedWorld") {
+        peak = Math.max(peak, ++active);
+        await new Promise((resolve) => setTimeout(resolve, 1));
+      }
+      if (method === "DOMSnapshot.captureSnapshot") {
+        expect(active).toBe(0);
+        expect(released).toBe(0);
+      }
+      if (method === "Page.createIsolatedWorld") {
+        expect(logs.filter((call) => call.method === "Accessibility.getFullAXTree")).toHaveLength(
+          count,
+        );
+      }
+      const result = await original(target, method, params);
+      if (
+        method === "Runtime.releaseObjectGroup" &&
+        String((params as { objectGroup?: string })?.objectGroup).startsWith(
+          "bsk-document-identity-",
+        )
+      ) {
+        active--;
+        released++;
+      }
+      return result as never;
+    };
+    cdp.send = (tabId, method, params) => cdp.sendToTarget!({ tabId }, method, params);
+    const facts = await captureObservationFacts(cdp, 4);
+    expect(facts.documents.every((doc) => doc.identity)).toBe(true);
+    expect(peak).toBe(Math.min(count, 4));
+    expect(active).toBe(0);
+    expect(released).toBe(count);
+    for (const method of [
+      "Page.createIsolatedWorld",
+      "Runtime.evaluate",
+      "Runtime.releaseObjectGroup",
+    ])
+      expect(logs.filter((call) => call.method === method)).toHaveLength(count);
+    expect(logs.filter((call) => call.method === "DOMSnapshot.captureSnapshot")).toHaveLength(1);
+    expect(logs.filter((call) => call.method === "Page.getFrameTree")).toHaveLength(0);
+  });
+
+  it("joins identity cleanup on cancellation without starting queued frames", async () => {
+    const frames: CdpFrame[] = Array.from({ length: 5 }, (_, i) => ({
+      frameId: `frame-${i}`,
+      target: { tabId: 4 },
+      ...(i ? { parentFrameId: "frame-0", ownerBackendNodeId: 90000 + i } : {}),
+    }));
+    const { cdp, logs } = fixture({ frames });
+    const original = cdp.sendToTarget!;
+    const controller = new AbortController();
+    let release!: () => void;
+    const gate = new Promise<void>((resolve) => {
+      release = resolve;
+    });
+    let ready!: () => void;
+    const blocked = new Promise<void>((resolve) => {
+      ready = resolve;
+    });
+    let held = 0;
+    cdp.sendToTarget = async (target, method, params) => {
+      const result = await original(target, method, params);
+      if (
+        method === "Runtime.releaseObjectGroup" &&
+        String((params as { objectGroup?: string })?.objectGroup).startsWith(
+          "bsk-document-identity-",
+        )
+      ) {
+        if (++held === 4) ready();
+        await gate;
+      }
+      return result as never;
+    };
+    cdp.send = (tabId, method, params) => cdp.sendToTarget!({ tabId }, method, params);
+    let settled = false;
+    const pending = captureObservationFacts(cdp, 4, controller.signal).finally(() => {
+      settled = true;
+    });
+    const rejected = expect(pending).rejects.toMatchObject({ name: "AbortError" });
+    await blocked;
+    controller.abort();
+    await Promise.resolve();
+    expect(settled).toBe(false);
+    release();
+    await rejected;
+    expect(held).toBe(4);
+    expect(logs.filter((call) => call.method === "Page.createIsolatedWorld")).toHaveLength(4);
+  });
+
+  it.each([
+    [{ after: { same: { element: 99 } } }, "omitted", false],
+    [{ after: { same: { unreadable: true } } }, "omitted", false],
+    [{ missingIdentity: true }, "document identity unverified", true],
+    [{}, "", true],
+  ] as const)("publishes identity integrity without silently losing content %j", async (options, notice, retained) => {
+    const { cdp } = fixture(options);
+    const result = await captureVomObservation(cdp, 4, "https://example.com");
+    expect(result.frames.some((frame) => frame.frameId === "same")).toBe(retained);
+    if (notice) expect(result.text).toContain(notice);
+    else expect(result.text).not.toContain("identity");
+    if (!retained) expect(result.text).not.toContain("document identity unverified");
+  });
+
   it("does not retry failed or missing documents and retains valid AX-only semantics", async () => {
     const { cdp, logs } = fixture({
       fail: "remote:DOMSnapshot.captureSnapshot",
@@ -151,6 +465,12 @@ describe("captureObservationFacts", () => {
     );
   });
 
+  it("keeps missing identity explicit without manufacturing a verified document", async () => {
+    const facts = await captureObservationFacts(fixture({ missingIdentity: true }).cdp, 4);
+    expect(facts.documents.every((doc) => !doc.identity)).toBe(true);
+    expect(facts.issues.filter((issue) => issue.reason === "identity-unverified")).toHaveLength(4);
+  });
+
   it("excludes overlay AX in its own document without excluding equal IDs elsewhere", async () => {
     const facts = await captureObservationFacts(fixture({ overlay: "remote" }).cdp, 4);
     const { documents } = semanticCapture(facts);
@@ -239,9 +559,7 @@ describe("captureObservationFacts", () => {
     await vi.waitFor(() => {
       if (mode === "worker-abort")
         expect(
-          calls.some(
-            (call) => call.target === "s3" && call.method === "Accessibility.getFullAXTree",
-          ),
+          calls.some((call) => call.target === "s3" && call.method === "Accessibility.enable"),
         ).toBe(true);
       else
         expect(
@@ -308,6 +626,8 @@ function childSnapshot(frameId: string, backendNodeId: number) {
     strings,
     documents: [
       {
+        scrollOffsetX: 0,
+        scrollOffsetY: 0,
         frameId,
         nodes: {
           parentIndex: [-1, 0],
@@ -335,8 +655,13 @@ function childSnapshot(frameId: string, backendNodeId: number) {
 describe("OOPIF capture", () => {
   it("captures and positions multiple OOPIF documents missing from the root snapshot", async () => {
     const sendToTarget = vi.fn(async (target, method) => {
+      if (method === "Runtime.evaluate") return { result: { value: { width: 300, height: 200 } } };
       if (method === "Page.getLayoutMetrics") {
-        return { cssLayoutViewport: { clientWidth: 300, clientHeight: 200, pageX: 0, pageY: 0 } };
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 300, clientHeight: 200, pageX: 0, pageY: 0 },
+        };
       }
       if (method === "DOMSnapshot.enable" || method === "Accessibility.enable") return {};
       if (method === "DOMSnapshot.captureSnapshot") {
@@ -358,7 +683,11 @@ describe("OOPIF capture", () => {
           return { model: { content: [x, 100, x + 300, 100, x + 300, 300, x, 300] } };
         }
         if (method === "Page.getLayoutMetrics") {
-          return { cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 } };
+          return {
+            visualViewport: { clientWidth: 1000 },
+            cssVisualViewport: { clientWidth: 1000 },
+            cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 },
+          };
         }
         throw new Error(`unexpected root ${method}`);
       }) as CdpRunner["send"],
@@ -436,7 +765,11 @@ describe("OOPIF capture", () => {
     };
     const reply = async (_target: unknown, method: string) => {
       if (method === "Page.getLayoutMetrics")
-        return { cssLayoutViewport: { clientWidth: 300, clientHeight: 200 } };
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 300, clientHeight: 200 },
+        };
       if (method === "DOMSnapshot.captureSnapshot")
         return typeof _target === "number" ? childSnapshot("main", 11) : snapshot;
       if (method === "DOM.getBoxModel")
@@ -494,7 +827,11 @@ describe("OOPIF capture", () => {
         if (method === "Accessibility.getFullAXTree") return { nodes: [] };
         if (method === "DOM.getBoxModel") throw new Error("owner geometry unavailable");
         if (method === "Page.getLayoutMetrics") {
-          return { cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 } };
+          return {
+            visualViewport: { clientWidth: 1000 },
+            cssVisualViewport: { clientWidth: 1000 },
+            cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 },
+          };
         }
         throw new Error(`unexpected root ${method}`);
       }) as CdpRunner["send"],
@@ -537,7 +874,7 @@ describe("OOPIF capture", () => {
       expect.objectContaining({ backendDOMNodeId: 101, frameId: "child" }),
     ]);
     expect(childDocument?.domNodes.find((node) => node.backendNodeId === 101)).toEqual(
-      expect.objectContaining({ rect: null, localRect: { x: 10, y: 20, w: 100, h: 40 } }),
+      expect.objectContaining({ rect: null, localRect: null, rendered: true }),
     );
   });
 });
@@ -547,6 +884,8 @@ function siblingCaptureFixture(
   beforeReply: (method: string, params: Record<string, unknown>) => Promise<void> = async () => {},
 ) {
   const document = (id: number, owners: number[], childIndexes: number[]) => ({
+    scrollOffsetX: 0,
+    scrollOffsetY: 0,
     frameId: `frame-${id}`,
     nodes: {
       parentIndex: [-1, ...owners.map(() => 0)],
@@ -578,7 +917,11 @@ function siblingCaptureFixture(
       await beforeReply(method, args);
       if (method === "DOMSnapshot.captureSnapshot") return snapshot;
       if (method === "Page.getLayoutMetrics")
-        return { cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 } };
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 },
+        };
       if (method === "DOM.getBoxModel")
         return { model: { content: [0, 0, 200, 0, 200, 100, 0, 100] } };
       if (method === "DOM.resolveNode") return { object: { objectId: String(args.backendNodeId) } };
@@ -782,7 +1125,11 @@ describe("snapshot document provenance", () => {
         (method === "DOMSnapshot.captureSnapshot"
           ? { ...f.snapshot, documents: [f.snapshot.documents[1]] }
           : method === "Page.getLayoutMetrics"
-            ? { cssLayoutViewport: { clientWidth: 200, clientHeight: 100 } }
+            ? {
+                visualViewport: { clientWidth: 1000 },
+                cssVisualViewport: { clientWidth: 1000 },
+                cssLayoutViewport: { clientWidth: 200, clientHeight: 100 },
+              }
             : {}) as T,
     };
     const facts = await captureObservationFacts(cdp, 4);
@@ -798,6 +1145,44 @@ describe("snapshot document provenance", () => {
 });
 
 describe("sibling frame measurement scheduling", () => {
+  it("batches same-target owner sizes without changing projected results", async () => {
+    const fixture = siblingCaptureFixture();
+    const original = fixture.cdp.send;
+    const methods: string[] = [];
+    fixture.cdp.send = async (tabId, method, params) => {
+      methods.push(method);
+      if (method === "Runtime.evaluate")
+        return {
+          result: {
+            deepSerializedValue: {
+              type: "array",
+              value: [100, 101, 102, 103, 104, 105, 200].map((backendNodeId) => ({
+                type: "array",
+                value: [
+                  { type: "node", value: { backendNodeId } },
+                  { type: "string", value: JSON.stringify({ width: 200, height: 100 }) },
+                ],
+              })),
+            },
+          },
+        } as never;
+      return original(tabId, method, params);
+    };
+    const captured = await captureObservationFacts(fixture.cdp, 4);
+    expect(captured.issues.filter((issue) => issue.stage === "geometry")).toEqual([]);
+    expect(captured.documents.map((doc) => doc.frame.frameId)).toEqual(
+      Array.from({ length: 8 }, (_, i) => `frame-${i}`),
+    );
+    expect(
+      captured.documents.find((doc) => doc.frame.frameId === "frame-7")?.domNodes[0].rect,
+    ).toEqual({ x: 0, y: 0, w: 200, h: 100 });
+    expect(methods.filter((method) => method === "DOM.getBoxModel")).toHaveLength(7);
+    expect(methods.filter((method) => method === "Runtime.evaluate")).toHaveLength(1);
+    expect(methods.filter((method) => method === "Runtime.releaseObjectGroup")).toHaveLength(1);
+    expect(methods).not.toContain("DOM.resolveNode");
+    expect(methods).not.toContain("Runtime.callFunctionOn");
+  });
+
   it("bounds concurrent reads, fills free slots and preserves breadth-first output despite reordered replies", async () => {
     const pending = new Map<number, () => void>();
     const fixture = siblingCaptureFixture(async (method, params) => {
@@ -912,3 +1297,69 @@ describe("sibling frame measurement scheduling", () => {
     );
   });
 });
+
+describe("AX frame scheduling", () => {
+  it.each([
+    false,
+    true,
+  ])("shares four workers across frames and drains cancellation=%s", async (cancel) => {
+    const f = siblingCaptureFixture();
+    const original = f.cdp.send;
+    const pending = new Map<string, () => void>();
+    let active = 0,
+      peak = 0;
+    f.cdp.send = async (tabId, method, params) => {
+      if (method !== "Accessibility.getFullAXTree") return original(tabId, method, params);
+      const frameId = (params as { frameId: string }).frameId;
+      active++;
+      peak = Math.max(peak, active);
+      try {
+        await new Promise<void>((resolve) => pending.set(frameId, resolve));
+        if (frameId === "frame-2") throw new Error("one AX frame unavailable");
+        return { nodes: [{ nodeId: frameId, frameId }] } as never;
+      } finally {
+        active--;
+      }
+    };
+    const controller = new AbortController();
+    let settled = false;
+    const capture = captureObservationFacts(f.cdp, 4, controller.signal);
+    const outcome = capture.then(
+      (facts) => ({ facts, error: undefined }),
+      (error) => ({ facts: undefined, error }),
+    );
+    void outcome.then(() => {
+      settled = true;
+    });
+    await vi.waitFor(() => expect(pending.size).toBe(4));
+    if (cancel) {
+      controller.abort();
+      pending.get("frame-3")!();
+      await new Promise((resolve) => setTimeout(resolve, 0));
+      expect(settled).toBe(false);
+      expect(pending.size).toBe(4);
+      for (const release of pending.values()) release();
+      expect((await outcome).error).toMatchObject({ name: "AbortError" });
+    } else {
+      for (let i = 3; i < 7; i++) {
+        pending.get(`frame-${i}`)!();
+        await vi.waitFor(() => expect(pending.has(`frame-${i + 1}`)).toBe(true));
+      }
+      for (const release of pending.values()) release();
+      const { facts, error } = await outcome;
+      expect(error).toBeUndefined();
+      expect(facts?.documents.map((doc) => doc.frame.frameId)).toEqual(
+        Array.from({ length: 8 }, (_, i) => `frame-${i}`),
+      );
+      expect(facts?.documents.find((doc) => doc.frame.frameId === "frame-2")?.axNodes).toEqual([]);
+      expect(facts?.issues).toContainEqual(
+        expect.objectContaining({ stage: "ax", frameId: "frame-2" }),
+      );
+      expect(facts?.documents.find((doc) => doc.frame.frameId === "frame-7")?.axNodes).toHaveLength(
+        1,
+      );
+    }
+    expect(peak).toBe(4);
+    expect(active).toBe(0);
+  });
+});

apps/extension/src/tools/vom/__tests__/capture.test.ts

@@ -215,7 +215,11 @@ function makeCdp(snapshot: unknown) {
       if (method === "DOMSnapshot.enable") return {};
       if (method === "DOMSnapshot.captureSnapshot") return snapshot;
       if (method === "Page.getLayoutMetrics") {
-        return { cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 } };
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
+        };
       }
       if (method === "Runtime.evaluate") {
         return {
@@ -277,6 +281,8 @@ describe("snapshot capture and hover", () => {
         if (method === "DOMSnapshot.captureSnapshot") return hoverTriggerSnapshotReply();
         if (method === "Page.getLayoutMetrics") {
           return {
+            visualViewport: { clientWidth: 1000 },
+            cssVisualViewport: { clientWidth: 1000 },
             cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
           };
         }
@@ -340,6 +346,8 @@ describe("snapshot capture and hover", () => {
         if (method === "DOMSnapshot.captureSnapshot") return twoHoverTriggerSnapshotReply();
         if (method === "Page.getLayoutMetrics") {
           return {
+            visualViewport: { clientWidth: 1000 },
+            cssVisualViewport: { clientWidth: 1000 },
             cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
           };
         }
@@ -388,6 +396,8 @@ describe("snapshot capture and hover", () => {
         if (method === "DOMSnapshot.captureSnapshot") return nestedHoverTriggerSnapshotReply();
         if (method === "Page.getLayoutMetrics") {
           return {
+            visualViewport: { clientWidth: 1000 },
+            cssVisualViewport: { clientWidth: 1000 },
             cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
           };
         }
@@ -733,6 +743,8 @@ describe("snapshot capture and hover", () => {
         if (method === "DOMSnapshot.captureSnapshot") return fakeSnapshotReply();
         if (method === "Page.getLayoutMetrics") {
           return {
+            visualViewport: { clientWidth: 1000 },
+            cssVisualViewport: { clientWidth: 1000 },
             cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 200 },
           };
         }
@@ -745,7 +757,7 @@ describe("snapshot capture and hover", () => {
     expect(div?.rect).toMatchObject({ y: 0, h: 600 });
   });
 
-  it("keeps CSS snapshot bounds independent of legacy metrics ratio", async () => {
+  it("normalizes raw snapshot bounds before viewport clipping", async () => {
     const S = ["html", "body", "div", "position", "fixed", "static", "pointer-events", "auto"];
     const i = (s: string) => S.indexOf(s);
     const snapshot = {
@@ -780,6 +792,8 @@ describe("snapshot capture and hover", () => {
         if (method === "DOMSnapshot.captureSnapshot") return snapshot;
         if (method === "Page.getLayoutMetrics") {
           return {
+            visualViewport: { clientWidth: 2000 },
+            cssVisualViewport: { clientWidth: 1000 },
             cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
             layoutViewport: { clientWidth: 2000, clientHeight: 1600 },
           };
@@ -797,8 +811,8 @@ describe("snapshot capture and hover", () => {
     expect(nodes.find((n) => n.backendNodeId === 12)?.localRect).toEqual({
       x: 0,
       y: 0,
-      w: 2000,
-      h: 1600,
+      w: 1000,
+      h: 800,
     });
   });
 
@@ -856,6 +870,8 @@ describe("snapshot capture and hover", () => {
         if (method === "DOMSnapshot.captureSnapshot") return snapshot;
         if (method === "Page.getLayoutMetrics") {
           return {
+            visualViewport: { clientWidth: 1000 },
+            cssVisualViewport: { clientWidth: 1000 },
             cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
           };
         }
@@ -946,6 +962,8 @@ describe("snapshot capture and hover", () => {
         if (method === "DOMSnapshot.captureSnapshot") return snapshot;
         if (method === "Page.getLayoutMetrics") {
           return {
+            visualViewport: { clientWidth: 1000 },
+            cssVisualViewport: { clientWidth: 1000 },
             cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
           };
         }
@@ -1035,6 +1053,8 @@ describe("snapshot capture and hover", () => {
         if (method === "DOMSnapshot.captureSnapshot") return snapshot;
         if (method === "Page.getLayoutMetrics") {
           return {
+            visualViewport: { clientWidth: 1000 },
+            cssVisualViewport: { clientWidth: 1000 },
             cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
           };
         }
@@ -1097,6 +1117,8 @@ describe("snapshot capture and hover", () => {
           },
         },
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "child",
           nodes: {
             parentIndex: [-1, 0, 1],
@@ -1119,6 +1141,8 @@ describe("snapshot capture and hover", () => {
           },
         },
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "nested",
           nodes: {
             parentIndex: [-1, 0],
@@ -1146,6 +1170,8 @@ describe("snapshot capture and hover", () => {
           if (method === "DOMSnapshot.captureSnapshot") return snapshot;
           if (method === "Page.getLayoutMetrics") {
             return {
+              visualViewport: { clientWidth: 1000 },
+              cssVisualViewport: { clientWidth: 1000 },
               cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
             };
           }
@@ -1225,6 +1251,8 @@ describe("snapshot capture and hover", () => {
         if (method === "DOMSnapshot.captureSnapshot") return snapshot;
         if (method === "Page.getLayoutMetrics") {
           return {
+            visualViewport: { clientWidth: 2000 },
+            cssVisualViewport: { clientWidth: 1000 },
             cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 100 },
             layoutViewport: { clientWidth: 2000, clientHeight: 1600 },
           };
@@ -1233,7 +1261,7 @@ describe("snapshot capture and hover", () => {
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
     const { nodes } = semanticCapture(await captureObservationFacts(cdp, 4)).captured;
-    expect(nodes.find((n) => n.backendNodeId === 12)?.rect?.y).toBe(400 - 100);
+    expect(nodes.find((n) => n.backendNodeId === 12)?.rect?.y).toBe(400 / 2 - 100);
   });
 
   it("collectOverlayExcludedBackendIds walks the pierced overlay host subtree", async () => {

apps/extension/src/tools/vom/__tests__/facts.test.ts

@@ -1,5 +1,6 @@
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 import { OVERLAY_HOST_MARKER_ATTR } from "@/lib/overlay-bridge";
+import { createCaptureCheckpoint } from "../capture-abort";
 import { buildDocumentIndex, type DecodedNode } from "../facts";
 import { decodeDocument, REQUESTED_STYLES } from "../snapshot";
 
@@ -76,7 +77,7 @@ describe("document facts", () => {
     );
     expect(nodes[0].attrs).toEqual({ "aria-hidden": "true", inert: "" });
     expect(nodes[0].layout).toEqual({
-      boundsSpace: "snapshot-document-css",
+      boundsSpace: "snapshot-document-layout",
       bounds: [10, 20, 120, 40],
       styles: {
         position: "static",
@@ -90,7 +91,23 @@ describe("document facts", () => {
     expect(nodes[0]).not.toHaveProperty("excluded");
   });
 
-  it("yields during large inputs so cancellation interrupts indexing", async () => {
+  it("keeps short blocks synchronous and checks cancellation after yielding", async () => {
+    const clock = vi.spyOn(performance, "now").mockReturnValue(0);
+    try {
+      const controller = new AbortController();
+      const checkpoint = createCaptureCheckpoint(controller.signal);
+      for (let i = 0; i < 20; i++) expect(checkpoint()).toBeUndefined();
+      clock.mockReturnValue(9);
+      const pending = checkpoint();
+      expect(pending).toBeInstanceOf(Promise);
+      controller.abort();
+      await expect(pending).rejects.toMatchObject({ name: "AbortError" });
+    } finally {
+      clock.mockRestore();
+    }
+  });
+
+  it("checks cancellation at bounded indexing blocks", async () => {
     const controller = new AbortController();
     const input = Array.from({ length: 100_000 }, (_, i) => node(i, i ? i - 1 : null));
     let reads = 0;

apps/extension/src/tools/vom/__tests__/form-state.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it, vi } from "vitest";
 import { type CdpRunner, cdpRunnerForTarget } from "../../shared";
-import { captureObservationFacts } from "../capture-coordinator";
+import { enrichFormControlStates } from "../form-capture";
+import { decodeDocument } from "../snapshot";
 
 interface Control {
   id: number;
@@ -77,21 +78,32 @@ function reply(entries: Array<[number, unknown]>) {
   };
 }
 
-function fakeCdp(groups: Control[][], evaluate: (params: Record<string, unknown>) => unknown) {
+async function fakeCdp(
+  groups: Control[][],
+  evaluate: (params: Record<string, unknown>) => unknown,
+) {
   const snap = snapshot(groups);
   const send = vi.fn(async (_tabId: number, method: string, params?: object) => {
-    if (method === "DOMSnapshot.captureSnapshot") return snap;
     if (method === "Runtime.evaluate") return evaluate(params as Record<string, unknown>);
     return {};
   });
-  return { send, cdp: { send: send as CdpRunner["send"] } };
+  const nodes = await decodeControls(snap);
+  return { send, cdp: { send: send as CdpRunner["send"] }, nodes };
+}
+
+async function decodeControls(snap: ReturnType<typeof snapshot>) {
+  return Promise.all(
+    snap.documents.map(async (doc) =>
+      (await decodeDocument(doc, snap.strings)).nodes.map((node) => ({ ...node, rect: null })),
+    ),
+  );
 }
 
 describe("form state identity", () => {
   it("matches reordered controls by identity and preserves controls missing from the batch", async () => {
     // The snapshot includes a shadow input. The runtime query skips it,
     // encounters a new input, and sees the remaining inputs in a new order.
-    const { cdp } = fakeCdp(
+    const { cdp, nodes } = await fakeCdp(
       [
         [
           { id: 10, value: "" },
@@ -106,23 +118,21 @@ describe("form state identity", () => {
           [11, state("alice@example.com")],
         ]),
     );
-    const captured = await captureObservationFacts(cdp, 7);
-    expect(captured.documents[0].domNodes.find((n) => n.backendNodeId === 10)).toMatchObject({
+    await enrichFormControlStates(cdp, 7, nodes);
+    expect(nodes[0].find((n) => n.backendNodeId === 10)).toMatchObject({
       formValue: "",
       formState: "empty",
       formPlaceholder: "snapshot placeholder",
     });
-    expect(captured.documents[0].domNodes.find((n) => n.backendNodeId === 11)).toMatchObject({
+    expect(nodes[0].find((n) => n.backendNodeId === 11)).toMatchObject({
       formValue: "alice@example.com",
     });
-    expect(captured.documents[0].domNodes.find((n) => n.backendNodeId === 12)).toMatchObject({
-      formValue: "上海",
-    });
-    expect(captured.documents[0].domNodes.some((n) => n.backendNodeId === 99)).toBe(false);
+    expect(nodes[0].find((n) => n.backendNodeId === 12)).toMatchObject({ formValue: "上海" });
+    expect(nodes[0].some((n) => n.backendNodeId === 99)).toBe(false);
   });
 
   it("does not shift state between frames when one frame is absent from the runtime batch", async () => {
-    const { cdp } = fakeCdp(
+    const { cdp, nodes } = await fakeCdp(
       [
         [],
         [{ id: 11, value: "inaccessible frame" }],
@@ -135,10 +145,8 @@ describe("form state identity", () => {
           [21, state("second frame")],
         ]),
     );
-    const captured = await captureObservationFacts(cdp, 7);
-    const controls = captured.documents
-      .filter((doc) => doc.frame.parentFrameId)
-      .flatMap((doc) => doc.domNodes);
+    await enrichFormControlStates(cdp, 7, nodes);
+    const controls = nodes.slice(1).flat();
     expect(controls.find((n) => n.backendNodeId === 11)?.formValue).toBe("inaccessible frame");
     expect(controls.find((n) => n.backendNodeId === 21)?.formValue).toBe("second frame");
     expect(controls.find((n) => n.backendNodeId === 31)?.formValue).toBe("third frame");
@@ -146,7 +154,6 @@ describe("form state identity", () => {
 
   it("keeps identical backend ids in different OOPIF targets separate", async () => {
     const sendToTarget = vi.fn(async (target, method) => {
-      if (method === "DOMSnapshot.captureSnapshot") return snapshot([[{ id: 11, value: "old" }]]);
       if (method === "Runtime.evaluate") return reply([[11, state(target.sessionId)]]);
       return {};
     });
@@ -155,13 +162,9 @@ describe("form state identity", () => {
     });
     const cdp = { send, sendToTarget } as unknown as CdpRunner;
     for (const sessionId of ["left-frame", "right-frame"]) {
-      const captured = await captureObservationFacts(
-        cdpRunnerForTarget(cdp, { tabId: 7, sessionId }),
-        7,
-      );
-      expect(captured.documents[0].domNodes.find((n) => n.backendNodeId === 11)?.formValue).toBe(
-        sessionId,
-      );
+      const nodes = await decodeControls(snapshot([[{ id: 11, value: "old" }]]));
+      await enrichFormControlStates(cdpRunnerForTarget(cdp, { tabId: 7, sessionId }), 7, nodes);
+      expect(nodes[0].find((n) => n.backendNodeId === 11)?.formValue).toBe(sessionId);
       expect(sendToTarget).toHaveBeenCalledWith(
         { tabId: 7, sessionId },
         "Runtime.releaseObjectGroup",
@@ -177,7 +180,7 @@ describe("form state identity", () => {
     "malformed",
     "invalid-state",
   ])("preserves snapshot data when enrichment is %s", async (mode) => {
-    const { cdp, send } = fakeCdp([[{ id: 11, value: "snapshot value" }]], () => {
+    const { cdp, send, nodes } = await fakeCdp([[{ id: 11, value: "snapshot value" }]], () => {
       if (mode === "unsupported") throw new Error("serialization unsupported");
       if (mode === "legacy") return { result: { value: { controls: [state("wrong value")] } } };
       const result = reply([
@@ -187,8 +190,8 @@ describe("form state identity", () => {
         result.result.deepSerializedValue.value[0].value[1].value = "not json";
       return result;
     });
-    const captured = await captureObservationFacts(cdp, 7);
-    expect(captured.documents[0].domNodes.find((n) => n.backendNodeId === 11)).toMatchObject({
+    expect(await enrichFormControlStates(cdp, 7, nodes)).toBe(mode !== "unsupported");
+    expect(nodes[0].find((n) => n.backendNodeId === 11)).toMatchObject({
       formValue: "snapshot value",
       formPlaceholder: "snapshot placeholder",
     });
@@ -197,18 +200,34 @@ describe("form state identity", () => {
 
   it("releases the batch's remote objects when capture is cancelled", async () => {
     const controller = new AbortController();
-    const { cdp, send } = fakeCdp([[{ id: 11, value: "old" }]], () => {
+    const { cdp, send, nodes } = await fakeCdp([[{ id: 11, value: "old" }]], () => {
       controller.abort();
       return reply([[11, state("new")]]);
     });
-    await expect(captureObservationFacts(cdp, 7, controller.signal)).rejects.toMatchObject({
+    await expect(enrichFormControlStates(cdp, 7, nodes, controller.signal)).rejects.toMatchObject({
       name: "AbortError",
     });
     expect(send).toHaveBeenCalledWith(7, "Runtime.releaseObjectGroup", expect.anything());
   });
 
+  it("does not report success when cancelled during object cleanup", async () => {
+    const controller = new AbortController();
+    const nodes = await decodeControls(snapshot([[{ id: 11, value: "old" }]]));
+    const cdp: CdpRunner = {
+      send: vi.fn(async (_tabId, method) => {
+        if (method === "Runtime.evaluate") return reply([[11, state("new")]]);
+        if (method === "Runtime.releaseObjectGroup") controller.abort();
+        return {};
+      }) as CdpRunner["send"],
+    };
+    await expect(enrichFormControlStates(cdp, 7, nodes, controller.signal)).rejects.toMatchObject({
+      name: "AbortError",
+    });
+    expect(cdp.send).toHaveBeenCalledWith(7, "Runtime.releaseObjectGroup", expect.anything());
+  });
+
   it("skips entries without node identity while still applying valid entries", async () => {
-    const { cdp } = fakeCdp(
+    const { cdp, nodes } = await fakeCdp(
       [
         [
           { id: 11, value: "snapshot value" },
@@ -225,24 +244,20 @@ describe("form state identity", () => {
         return result;
       },
     );
-    const captured = await captureObservationFacts(cdp, 7);
-    expect(captured.documents[0].domNodes.find((n) => n.backendNodeId === 11)?.formValue).toBe(
-      "snapshot value",
-    );
-    expect(captured.documents[0].domNodes.find((n) => n.backendNodeId === 12)?.formValue).toBe(
-      "live value",
-    );
+    await enrichFormControlStates(cdp, 7, nodes);
+    expect(nodes[0].find((n) => n.backendNodeId === 11)?.formValue).toBe("snapshot value");
+    expect(nodes[0].find((n) => n.backendNodeId === 12)?.formValue).toBe("live value");
   });
 
   it.each([
     "password",
     "text",
   ])("redacts a sensitive %s control after identity matching", async (type) => {
-    const { cdp } = fakeCdp([[{ id: 11, value: "secret", type }]], () =>
+    const { cdp, nodes } = await fakeCdp([[{ id: 11, value: "secret", type }]], () =>
       reply([[11, { ...state("secret"), sensitive: true }]]),
     );
-    const captured = await captureObservationFacts(cdp, 7);
-    const control = captured.documents[0].domNodes.find((n) => n.backendNodeId === 11);
+    await enrichFormControlStates(cdp, 7, nodes);
+    const control = nodes[0].find((n) => n.backendNodeId === 11);
     expect(control?.formState).toBe("filled");
     expect(control?.formValue).toBeUndefined();
     expect(control?.formDefaultValue).toBeUndefined();
@@ -259,7 +274,7 @@ describe("form state identity", () => {
       defaultValue: "",
       placeholder: "",
     }));
-    const { cdp, send } = fakeCdp([controls], (params) => {
+    const { cdp, send, nodes } = await fakeCdp([controls], (params) => {
       const doc = {
         querySelectorAll: (selector: string) =>
           selector === "input,textarea,select" ? elements : [],
@@ -270,13 +285,9 @@ describe("form state identity", () => {
       expect(entries).toHaveLength(250);
       return reply(entries.map(([element, json]) => [element.backendNodeId, JSON.parse(json)]));
     });
-    const captured = await captureObservationFacts(cdp, 7);
-    expect(captured.documents[0].domNodes.find((n) => n.backendNodeId === 250)?.formValue).toBe(
-      "live 250",
-    );
-    expect(captured.documents[0].domNodes.find((n) => n.backendNodeId === 251)?.formValue).toBe(
-      "old",
-    );
+    await enrichFormControlStates(cdp, 7, nodes);
+    expect(nodes[0].find((n) => n.backendNodeId === 250)?.formValue).toBe("live 250");
+    expect(nodes[0].find((n) => n.backendNodeId === 251)?.formValue).toBe("old");
     expect(send.mock.calls.filter(([, method]) => method === "Runtime.evaluate")).toHaveLength(1);
     expect(
       send.mock.calls.filter(([, method]) => method === "Runtime.releaseObjectGroup"),

apps/extension/src/tools/vom/capture-abort.ts

@@ -0,0 +1,40 @@
+function captureAbortError(): Error {
+  const error = new Error("observation aborted");
+  error.name = "AbortError";
+  return error;
+}
+
+export function isAbortError(error: unknown): boolean {
+  return (
+    typeof error === "object" &&
+    error !== null &&
+    (error as { name?: string }).name === "AbortError"
+  );
+}
+
+export function throwIfAborted(signal: AbortSignal | undefined): void {
+  if (signal?.aborted) throw captureAbortError();
+}
+
+/** Check at bounded work blocks; yield only after a processing slice is spent.
+ * Each caller owns its deadline, so unrelated captures do not share state. */
+export function createCaptureCheckpoint(signal?: AbortSignal): () => Promise<void> | undefined {
+  throwIfAborted(signal);
+  let deadline = performance.now() + 8;
+  return () => {
+    throwIfAborted(signal);
+    if (performance.now() < deadline) return;
+    return new Promise<void>((resolve) => {
+      const channel = new MessageChannel();
+      channel.port1.onmessage = () => {
+        channel.port1.close();
+        channel.port2.close();
+        resolve();
+      };
+      channel.port2.postMessage(null);
+    }).then(() => {
+      throwIfAborted(signal);
+      deadline = performance.now() + 8;
+    });
+  };
+}

apps/extension/src/tools/vom/capture-coordinator.ts

@@ -7,14 +7,13 @@ import {
 import { cssViewport, GeometryContext } from "../geometry/frame-context";
 import { type CdpRunner, cdpRunnerForTarget } from "../shared";
 import { collectOverlayExcludedBackendIds } from "./capture";
-import type { CapturedSceneInput } from "./facts";
 import {
-  buildDocumentIndex,
-  type CaptureIssue,
-  isCaptureAbort,
-  type ObservationFacts,
-  throwCaptureAborted,
-} from "./facts";
+  isAbortError as isCaptureAbort,
+  throwIfAborted as throwCaptureAborted,
+} from "./capture-abort";
+import { verifyDocumentIdentity } from "./document-identity";
+import type { CapturedSceneInput, DocumentIdentity } from "./facts";
+import { buildDocumentIndex, type CaptureIssue, type ObservationFacts } from "./facts";
 import { enrichFormControlStates } from "./form-capture";
 import {
   buildFrameDocuments,
@@ -22,13 +21,14 @@ import {
   type FrameDocument,
   type FrameOwnedAxNode,
 } from "./frame-document";
-import { type NormalizedDocument, normalizeSnapshot } from "./normalize";
+import { type NormalizedFrameDocument, normalizeSnapshot } from "./normalize";
 import { describeSnapshotFrames, REQUESTED_STYLES, type SnapshotReply } from "./snapshot";
 
 interface TargetBatch<T extends FrameOwnedAxNode> {
   target: CdpTarget;
   frames: CdpFrame[];
-  documents: NormalizedDocument[];
+  snapshotAttachmentId?: string;
+  documents: NormalizedFrameDocument[];
   ax: FrameAxBatch<T>[];
   fallbackExcluded: Set<number>;
   snapshotFrameIds?: Set<string>;
@@ -37,7 +37,7 @@ interface TargetBatch<T extends FrameOwnedAxNode> {
 
 /** A fixed worker pool scoped to one capture; each worker issues at most one
  * collection request at a time. Geometry has its own measurement-phase bound. */
-async function collectTargets<T>(
+async function collectTasks<T>(
   items: readonly T[],
   collect: (item: T) => Promise<void>,
   signal?: AbortSignal,
@@ -114,7 +114,8 @@ export async function captureObservationFacts<T extends FrameOwnedAxNode>(
   const unavailable = (batch: TargetBatch<T>, stage: CaptureIssue["stage"], frameId?: string) =>
     issues.push({ target: batch.target, frameId, stage, reason: "capture-unavailable" });
   let firstFailure: unknown;
-  await collectTargets(
+  const axReady = new Set<TargetBatch<T>>();
+  await collectTasks(
     batches,
     async (batch) => {
       const scoped = cdpRunnerForTarget(cdp, batch.target);
@@ -122,6 +123,7 @@ export async function captureObservationFacts<T extends FrameOwnedAxNode>(
         throwCaptureAborted(signal);
         await scoped.send(tabId, "DOMSnapshot.enable", {});
         throwCaptureAborted(signal);
+        batch.snapshotAttachmentId = cdp.getAttachmentId?.(tabId);
         const snapshot = await scoped.send<SnapshotReply>(tabId, "DOMSnapshot.captureSnapshot", {
           computedStyles: REQUESTED_STYLES,
           includePaintOrder: true,
@@ -148,7 +150,7 @@ export async function captureObservationFacts<T extends FrameOwnedAxNode>(
         const formsAvailable = await enrichFormControlStates(
           scoped,
           tabId,
-          batch.documents.map((doc) => doc.domNodes),
+          batch.documents.map((doc) => doc.nodes),
           signal,
         );
         throwCaptureAborted(signal);
@@ -181,26 +183,48 @@ export async function captureObservationFacts<T extends FrameOwnedAxNode>(
         unavailable(batch, "ax");
         return;
       }
-      for (const frame of batch.frames) {
-        try {
-          throwCaptureAborted(signal);
-          const result = await scoped.send<{ nodes?: T[] }>(
-            tabId,
-            "Accessibility.getFullAXTree",
-            frame.frameId === "root" ? {} : { frameId: frame.frameId },
-          );
-          throwCaptureAborted(signal);
-          batch.ax.push({ frame, nodes: result.nodes ?? [] });
-        } catch (error) {
-          throwCaptureAborted(signal);
-          if (isCaptureAbort(error)) throw error;
-          firstFailure ??= error;
-          unavailable(batch, "ax", frame.frameId);
-        }
+      axReady.add(batch);
+    },
+    signal,
+  );
+
+  // Schedule AX by frame across all ready targets, rather than nesting pools.
+  // Keep result slots in source order even when CDP replies arrive out of order.
+  const axTasks: { batch: TargetBatch<T>; frame: CdpFrame; result?: FrameAxBatch<T> }[] =
+    batches.flatMap((batch) =>
+      axReady.has(batch) ? batch.frames.map((frame) => ({ batch, frame })) : [],
+    );
+  await collectTasks(
+    axTasks,
+    async (task) => {
+      const { batch, frame } = task;
+      try {
+        throwCaptureAborted(signal);
+        const result = await cdpRunnerForTarget(cdp, batch.target).send<{ nodes?: T[] }>(
+          tabId,
+          "Accessibility.getFullAXTree",
+          frame.frameId === "root" ? {} : { frameId: frame.frameId },
+        );
+        throwCaptureAborted(signal);
+        task.result = { frame, nodes: result.nodes ?? [] };
+      } catch (error) {
+        throwCaptureAborted(signal);
+        if (isCaptureAbort(error)) throw error;
+        firstFailure ??= error;
+        unavailable(batch, "ax", frame.frameId);
       }
     },
     signal,
   );
+  for (const task of axTasks) if (task.result) task.batch.ax.push(task.result);
+
+  let viewport = { width: 0, height: 0 };
+  try {
+    const measured = cssViewport(await geometry.layoutMetrics({ tabId }));
+    viewport = { width: measured.width, height: measured.height };
+  } catch (error) {
+    if (isCaptureAbort(error)) throw error;
+  }
 
   // A snapshot claim outranks an old graph hint. Conflicting actual claims
   // cannot be resolved by completion order or by overwriting a frameId map.
@@ -222,6 +246,56 @@ export async function captureObservationFacts<T extends FrameOwnedAxNode>(
         !claims.has(frame.frameId) || claims.get(frame.frameId) === cdpTargetKey(batch.target),
     ),
   );
+  const rootBatch = batches.find((batch) => !batch.target.sessionId);
+  const rootFrameId =
+    rootBatch?.rootFrameId ?? graph?.rootFrameId ?? rootBatch?.frames[0]?.frameId ?? "root";
+  const ownershipInvalid = new Set(invalid);
+  const identities = new Map<string, DocumentIdentity>();
+  const selected = new Map(currentFrames.map((frame) => [frame.frameId, frame]));
+  const checks = batches.flatMap((batch) => {
+    const docs = new Map(batch.documents.map((doc) => [doc.frame.frameId, doc]));
+    return batch.frames
+      .filter(
+        (frame) =>
+          !invalid.has(frame.frameId) &&
+          cdpTargetKey(selected.get(frame.frameId)!.target) === cdpTargetKey(batch.target),
+      )
+      .map((frame) => ({ batch, frame, doc: docs.get(frame.frameId) }));
+  });
+  await collectTasks(
+    checks,
+    async ({ batch, frame, doc }) => {
+      throwCaptureAborted(signal);
+      if (!batch.snapshotAttachmentId || doc?.documentElementBackendNodeId === undefined) {
+        issues.push({
+          target: frame.target,
+          frameId: frame.frameId,
+          stage: "identity",
+          reason: "identity-unverified",
+        });
+        return;
+      }
+      const identity: DocumentIdentity = {
+        attachmentId: batch.snapshotAttachmentId,
+        target: frame.target,
+        frameId: frame.frameId,
+        documentElementBackendNodeId: doc.documentElementBackendNodeId,
+      };
+      const verified = await verifyDocumentIdentity(cdp, identity, signal);
+      const status = cdp.getAttachmentId?.(tabId) === identity.attachmentId ? verified : "changed";
+      if (status === "current") identities.set(frame.frameId, identity);
+      else {
+        invalid.add(frame.frameId);
+        issues.push({
+          target: frame.target,
+          frameId: frame.frameId,
+          stage: "identity",
+          reason: status === "changed" ? "document-changed" : "identity-unavailable",
+        });
+      }
+    },
+    signal,
+  );
   const children = new Map<string, string[]>();
   for (const frame of currentFrames) {
     if (!frame.parentFrameId) continue;
@@ -239,7 +313,7 @@ export async function captureObservationFacts<T extends FrameOwnedAxNode>(
     }
   }
   for (const frame of currentFrames) {
-    if (invalid.has(frame.frameId))
+    if (ownershipInvalid.has(frame.frameId))
       issues.push({
         target: frame.target,
         frameId: frame.frameId,
@@ -247,10 +321,12 @@ export async function captureObservationFacts<T extends FrameOwnedAxNode>(
         reason: "frame-ownership-unresolved",
       });
   }
-  const rootBatch = batches.find((batch) => !batch.target.sessionId);
-  const rootFrameId =
-    rootBatch?.rootFrameId ?? graph?.rootFrameId ?? rootBatch?.frames[0]?.frameId ?? "root";
-  if (invalid.has(rootFrameId)) throw new Error("observation root document ownership is ambiguous");
+  if (invalid.has(rootFrameId))
+    throw new Error(
+      ownershipInvalid.has(rootFrameId)
+        ? "observation root document ownership is ambiguous"
+        : "observation document identity changed or could not be verified; observe again",
+    );
   const frames = currentFrames.filter((frame) => !invalid.has(frame.frameId));
   const frameById = new Map(frames.map((frame) => [frame.frameId, frame]));
   const belongs = (frame: CdpFrame) => {
@@ -270,7 +346,10 @@ export async function captureObservationFacts<T extends FrameOwnedAxNode>(
     {
       nodes: [],
       rootFrameId,
-      frameNodes: new Map([...decoded].map(([id, doc]) => [id, doc.domNodes])),
+      frameNodes: new Map([...decoded].map(([id, doc]) => [id, doc.nodes])),
+      frameExcludedBackendNodeIds: new Map(
+        [...decoded].map(([id, doc]) => [id, doc.index.excludedBackendNodeIds]),
+      ),
     },
     signal,
     (frame) =>
@@ -281,21 +360,21 @@ export async function captureObservationFacts<T extends FrameOwnedAxNode>(
         reason: "frame-ownership-unresolved",
       }),
   );
-  let viewport = { width: 0, height: 0 };
-  try {
-    const measured = cssViewport(await geometry.layoutMetrics({ tabId }));
-    viewport = { width: measured.width, height: measured.height };
-  } catch (error) {
-    if (isCaptureAbort(error)) throw error;
-  }
   const facts: ObservationFacts<T>["documents"][number][] = [];
   for (const document of documents) {
     const doc = decoded.get(document.frameId);
     const index = doc?.index ?? (await buildDocumentIndex([], signal));
     const fallback = groups.get(cdpTargetKey(document.target))?.fallbackExcluded;
-    const { domNodes, axNodes, contextScopeId: _scope, ...frame } = document;
+    const {
+      domNodes,
+      axNodes,
+      contextScopeId: _scope,
+      excludedBackendNodeIds: _excluded,
+      ...frame
+    } = document;
     facts.push({
       frame,
+      identity: identities.get(document.frameId),
       index: fallback?.size ? { ...index, excludedBackendNodeIds: fallback } : index,
       domNodes,
       axNodes,

apps/extension/src/tools/vom/capture-types.ts

@@ -0,0 +1,37 @@
+import type { Rect } from "@browser-skill/vom";
+
+export interface CapturedNode {
+  backendNodeId: number;
+  parentBackendNodeId: number | null;
+  frameId?: string;
+  /** Owning iframe backend node id; `null` for the top-level document. */
+  ownerFrameBackendNodeId?: number | null;
+  tag: string;
+  attrs: Record<string, string>;
+  /** Top-level viewport-relative CSS px, clipped to the owning frame viewport. */
+  rect: Rect | null;
+  /** Frame-local viewport-relative CSS px before top-level projection. */
+  localRect?: Rect | null;
+  paintOrder: number;
+  position: string;
+  pointerEvents: string;
+  /**
+   * computed `cursor`. `cursor: pointer` is the strongest CDP-free signal
+   * that a non-semantic element (a `<div>`/`<span>` with a click handler)
+   * is actually an interactive control — used by the adapter to surface
+   * custom buttons/checkboxes the AX tree drops as `generic`. Optional like
+   * `textContent`: the live parser always sets it, hand-built fixtures may not.
+   */
+  cursor?: string;
+  /**
+   * Whether the live DOM snapshot provides a painted, non-hidden box for this
+   * node. Semantic resolution uses this only for DOM fallback nodes; AX-backed
+   * nodes remain authoritative even when they are outside the viewport.
+   */
+  rendered?: boolean;
+  textContent?: string;
+  formState?: "empty" | "filled" | "default";
+  formValue?: string;
+  formDefaultValue?: string;
+  formPlaceholder?: string;
+}

apps/extension/src/tools/vom/capture.ts

@@ -3,14 +3,15 @@
 import { evaluateHoverTrigger } from "@/lib/hover-trigger-policy";
 import { OVERLAY_HOST_SELECTOR } from "../../lib/overlay-bridge";
 import type { CdpRunner } from "../shared";
-import type { CapturedNode, CapturedSurfaceProbe } from "./facts";
+import type { CapturedNode } from "./capture-types";
+import type { CapturedSurfaceProbe } from "./facts";
 
 export type {
   CapturedNode,
   CapturedSurfaceProbe,
 } from "./facts";
 
-import { isCaptureAbort as isAbortError, throwCaptureAborted as throwIfAborted } from "./facts";
+import { isAbortError, throwIfAborted } from "./capture-abort";
 import { clearHover, ProbeBudget, waitForHover } from "./hover-perception";
 
 interface RuntimeEvaluateReply {

apps/extension/src/tools/vom/document-identity.ts

@@ -0,0 +1,53 @@
+import type { CdpRunner } from "../shared";
+import { sendToCdpTarget } from "../shared";
+import { isAbortError, throwIfAborted } from "./capture-abort";
+import type { DocumentIdentity } from "./facts";
+
+/** Compare the snapshot root with the current root in that exact frame.
+ * Deep serialization supplies the backend ID without a separate describeNode. */
+export async function verifyDocumentIdentity(
+  cdp: CdpRunner,
+  identity: DocumentIdentity,
+  signal?: AbortSignal,
+): Promise<"current" | "changed" | "unavailable"> {
+  const attached = () => cdp.getAttachmentId?.(identity.target.tabId) === identity.attachmentId;
+  throwIfAborted(signal);
+  if (!attached()) return "changed";
+  const objectGroup = `bsk-document-identity-${crypto.randomUUID()}`;
+  const send = <T>(method: string, params: object) => {
+    throwIfAborted(signal);
+    return sendToCdpTarget<T>(cdp, identity.target, method, params);
+  };
+  try {
+    const world = await send<{ executionContextId: number }>("Page.createIsolatedWorld", {
+      frameId: identity.frameId,
+      worldName: "bsk-document-identity",
+    });
+    const reply = await send<{
+      result?: { deepSerializedValue?: { type: string; value?: { backendNodeId?: number } } };
+    }>("Runtime.evaluate", {
+      expression: "document.documentElement",
+      contextId: world.executionContextId,
+      objectGroup,
+      serializationOptions: {
+        serialization: "deep",
+        additionalParameters: { maxNodeDepth: 0, includeShadowTree: "none" },
+      },
+    });
+    if (!attached()) return "changed";
+    const root = reply.result?.deepSerializedValue;
+    if (root?.type === "null") return "changed";
+    const id = root?.type === "node" ? root.value?.backendNodeId : undefined;
+    if (id === undefined) return "unavailable";
+    return id === identity.documentElementBackendNodeId ? "current" : "changed";
+  } catch (error) {
+    throwIfAborted(signal);
+    if (isAbortError(error)) throw error;
+    return attached() ? "unavailable" : "changed";
+  } finally {
+    await sendToCdpTarget(cdp, identity.target, "Runtime.releaseObjectGroup", {
+      objectGroup,
+    }).catch(() => {});
+    throwIfAborted(signal);
+  }
+}

apps/extension/src/tools/vom/facts.ts

@@ -1,64 +1,14 @@
-import type { Rect, Viewport } from "@browser-skill/vom";
+import type { Viewport } from "@browser-skill/vom";
 import type { CdpFrame, CdpTarget } from "@/browser-driver/frame-graph";
 import { isOverlayHostNode } from "@/lib/overlay-bridge";
 import type { FrameProjectionIssue } from "../geometry/coordinate-types";
+import { createCaptureCheckpoint } from "./capture-abort";
+import type { CapturedNode } from "./capture-types";
 import type { FrameOwnedAxNode } from "./frame-document";
 
-export interface CapturedNode {
-  backendNodeId: number;
-  parentBackendNodeId: number | null;
-  frameId?: string;
-  /** Owning iframe backend node id; `null` for the top-level document. */
-  ownerFrameBackendNodeId?: number | null;
-  tag: string;
-  attrs: Record<string, string>;
-  /** Top-level viewport-relative CSS px, clipped to the owning frame viewport. */
-  rect: Rect | null;
-  /** Frame-local viewport-relative CSS px before top-level projection. */
-  localRect?: Rect | null;
-  paintOrder: number;
-  position: string;
-  pointerEvents: string;
-  /**
-   * computed `cursor`. `cursor: pointer` is the strongest CDP-free signal
-   * that a non-semantic element (a `<div>`/`<span>` with a click handler)
-   * is actually an interactive control — used by the adapter to surface
-   * custom buttons/checkboxes the AX tree drops as `generic`. Optional like
-   * `textContent`: the live parser always sets it, hand-built fixtures may not.
-   */
-  cursor?: string;
-  /**
-   * Whether the live DOM snapshot provides a painted, non-hidden box for this
-   * node. Semantic resolution uses this only for DOM fallback nodes; AX-backed
-   * nodes remain authoritative even when they are outside the viewport.
-   */
-  rendered?: boolean;
-  textContent?: string;
-  formState?: "empty" | "filled" | "default";
-  formValue?: string;
-  formDefaultValue?: string;
-  formPlaceholder?: string;
-}
-
-export interface CapturedSurfaceProbe {
-  triggerBackendNodeId: number;
-  triggerPoint?: { x: number; y: number };
-  triggerAction: "hover" | "focus" | string;
-  subItems: string[];
-  confidence?: "high" | "medium" | "low";
-}
-
-/** Narrow input shared by the existing semantic scene/hover consumers. */
-export interface CapturedSceneInput {
-  nodes: CapturedNode[];
-  viewport: Viewport;
-  rootFrameId?: string;
-  excludedBackendNodeIds: ReadonlySet<number>;
-}
-
-/** Bounds retain their snapshot document CSS units until normalization. */
+/** Bounds retain their raw snapshot document layout units until normalization. */
 export interface SnapshotLayout {
-  readonly boundsSpace: "snapshot-document-css";
+  readonly boundsSpace: "snapshot-document-layout";
   bounds?: number[];
   styles: Readonly<Record<string, string>>;
 }
@@ -82,78 +32,40 @@ export interface DecodedDocument {
   nodes: DecodedNode[];
 }
 
-export interface CaptureIssue {
-  /** Owner failure or inherited blockage; absent for other geometry failures. */
-  projectionIssue?: FrameProjectionIssue;
-  target: CdpTarget;
-  frameId?: string;
-  stage: "dom" | "ax" | "ownership" | "geometry" | "forms";
-  reason: "capture-unavailable" | "frame-ownership-unresolved" | "geometry-unavailable";
-}
-
-export interface DocumentFacts<T extends FrameOwnedAxNode> {
-  readonly frame: CdpFrame;
-  readonly index: DocumentIndex;
-  readonly domNodes: CapturedNode[];
-  readonly axNodes: T[];
-}
-
-export interface ObservationFacts<T extends FrameOwnedAxNode> {
-  readonly rootFrameId: string;
-  readonly viewport: Viewport;
-  readonly documents: readonly DocumentFacts<T>[];
-  readonly issues: readonly CaptureIssue[];
-  readonly startedAt: number;
-  readonly finishedAt: number;
-}
-
-export function throwCaptureAborted(signal?: AbortSignal): void {
-  if (signal?.aborted) throw new DOMException("observation aborted", "AbortError");
-}
-
-export function isCaptureAbort(error: unknown): boolean {
-  return error instanceof Error && error.name === "AbortError";
-}
-
-/** Called only at bounded block boundaries, not once per node. */
-export async function captureCheckpoint(signal?: AbortSignal): Promise<void> {
-  throwCaptureAborted(signal);
-  await new Promise<void>((resolve) => {
-    const channel = new MessageChannel();
-    channel.port1.onmessage = () => {
-      channel.port1.close();
-      channel.port2.close();
-      resolve();
-    };
-    channel.port2.postMessage(null);
-  });
-  throwCaptureAborted(signal);
-}
-
 /** All snapshot nodes participate, including document and shadow roots. This
  * preserves overlay propagation when the semantic adapter omits those nodes. */
 export async function buildDocumentIndex<T extends DecodedNode>(
   input: readonly T[],
   signal?: AbortSignal,
 ): Promise<DocumentIndex<T>> {
+  const checkpoint = createCaptureCheckpoint(signal);
   const nodes = new Map<number, T>();
   const overlayByNode = new Map<number, boolean>();
   const excludedBackendNodeIds = new Set<number>();
   for (let i = 0; i < input.length; i++) {
-    if (i % 256 === 0) await captureCheckpoint(signal);
+    if (i % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
     const node = input[i];
     nodes.set(node.backendNodeId, node);
   }
   let work = 0;
   for (const node of input) {
-    if (work++ % 256 === 0) await captureCheckpoint(signal);
+    if (work++ % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
     if (overlayByNode.has(node.backendNodeId)) continue;
     const path: DecodedNode[] = [];
     const visiting = new Set<number>();
     let current: DecodedNode | undefined = node;
     let overlay = false;
     while (current && !overlayByNode.has(current.backendNodeId)) {
-      if (work++ % 256 === 0) await captureCheckpoint(signal);
+      if (work++ % 256 === 0) {
+        const pending = checkpoint();
+        if (pending) await pending;
+      }
       if (visiting.has(current.backendNodeId)) {
         // Only an overlay inside the cycle may mark the cycle and its descendants.
         overlay = path
@@ -172,7 +84,10 @@ export async function buildDocumentIndex<T extends DecodedNode>(
     if (current && overlayByNode.has(current.backendNodeId))
       overlay = overlayByNode.get(current.backendNodeId)!;
     for (let i = path.length - 1; i >= 0; i--) {
-      if (work++ % 256 === 0) await captureCheckpoint(signal);
+      if (work++ % 256 === 0) {
+        const pending = checkpoint();
+        if (pending) await pending;
+      }
       const item = path[i];
       overlay = overlay || isOverlayHostNode(item.tag, Object.keys(item.attrs));
       overlayByNode.set(item.backendNodeId, overlay);
@@ -181,3 +96,60 @@ export async function buildDocumentIndex<T extends DecodedNode>(
   }
   return { nodes, excludedBackendNodeIds };
 }
+
+export interface DocumentIdentity {
+  attachmentId: string;
+  target: CdpTarget;
+  frameId: string;
+  documentElementBackendNodeId: number;
+}
+
+/** Narrow input shared by the existing semantic scene/hover consumers. */
+export interface CapturedSceneInput {
+  nodes: CapturedNode[];
+  viewport: Viewport;
+  rootFrameId?: string;
+  excludedBackendNodeIds: ReadonlySet<number>;
+}
+
+export interface CaptureIssue {
+  /** Owner failure or inherited blockage; absent for other geometry failures. */
+  projectionIssue?: FrameProjectionIssue;
+  target: CdpTarget;
+  frameId?: string;
+  stage: "dom" | "ax" | "identity" | "ownership" | "geometry" | "forms";
+  reason:
+    | "document-changed"
+    | "identity-unavailable"
+    | "identity-unverified"
+    | "capture-unavailable"
+    | "frame-ownership-unresolved"
+    | "geometry-unavailable";
+}
+
+export interface DocumentFacts<T extends FrameOwnedAxNode> {
+  readonly frame: CdpFrame;
+  readonly identity?: DocumentIdentity;
+  readonly index: DocumentIndex;
+  readonly domNodes: CapturedNode[];
+  readonly axNodes: T[];
+}
+
+export interface ObservationFacts<T extends FrameOwnedAxNode> {
+  readonly rootFrameId: string;
+  readonly viewport: Viewport;
+  readonly documents: readonly DocumentFacts<T>[];
+  readonly issues: readonly CaptureIssue[];
+  readonly startedAt: number;
+  readonly finishedAt: number;
+}
+
+export interface CapturedSurfaceProbe {
+  triggerBackendNodeId: number;
+  triggerPoint?: { x: number; y: number };
+  triggerAction: "hover" | "focus" | string;
+  subItems: string[];
+  confidence?: "high" | "medium" | "low";
+}
+
+export type { CapturedNode } from "./capture-types";

apps/extension/src/tools/vom/form-capture.ts

@@ -1,6 +1,6 @@
 import type { CdpRunner } from "../shared";
-import type { CapturedNode } from "./facts";
-import { isCaptureAbort as isAbortError, throwCaptureAborted as throwIfAborted } from "./facts";
+import { isAbortError, throwIfAborted } from "./capture-abort";
+import type { CapturedNode } from "./capture-types";
 
 interface RuntimeEvaluateReply {
   result?: { deepSerializedValue?: DeepSerializedValue };

apps/extension/src/tools/vom/frame-document.ts

@@ -4,8 +4,8 @@ import {
   type CdpTarget,
   cdpTargetKey,
 } from "@/browser-driver/frame-graph";
-import type { CapturedNode } from "./facts";
-import { captureCheckpoint } from "./facts";
+import { createCaptureCheckpoint } from "./capture-abort";
+import type { CapturedNode } from "./capture-types";
 
 export interface FrameOwnedAxNode {
   nodeId: string;
@@ -32,6 +32,7 @@ export interface FrameDomInput {
   nodes: CapturedNode[];
   rootFrameId?: string;
   frameNodes?: ReadonlyMap<string, CapturedNode[]>;
+  frameExcludedBackendNodeIds?: ReadonlyMap<string, ReadonlySet<number>>;
 }
 
 interface Ownership {
@@ -72,6 +73,7 @@ export async function buildFrameDocuments<T extends FrameOwnedAxNode>(
   signal?: AbortSignal,
   unresolved?: (frame: CdpFrame) => void,
 ): Promise<FrameDocument<T>[]> {
+  const checkpoint = createCaptureCheckpoint(signal);
   let work = 0;
   const frames = frameList(graph, batches);
   const frameById = new Map(frames.map((frame) => [frame.frameId, frame]));
@@ -81,7 +83,10 @@ export async function buildFrameDocuments<T extends FrameOwnedAxNode>(
   const backendOwner = new Map<string, string>();
   for (const frame of frames) {
     for (const node of domNodesForFrame(frame.frameId)) {
-      if (work++ % 256 === 0) await captureCheckpoint(signal);
+      if (work++ % 256 === 0) {
+        const pending = checkpoint();
+        if (pending) await pending;
+      }
       backendOwner.set(targetBackendKey(frame.target, node.backendNodeId), frame.frameId);
     }
   }
@@ -90,18 +95,24 @@ export async function buildFrameDocuments<T extends FrameOwnedAxNode>(
   for (const batch of batches) {
     const nodeById = new Map<string, T>();
     for (const node of batch.nodes) {
-      if (work++ % 256 === 0) await captureCheckpoint(signal);
+      if (work++ % 256 === 0) {
+        const pending = checkpoint();
+        if (pending) await pending;
+      }
       nodeById.set(node.nodeId, node);
     }
     let reported = false;
     const ownershipByNodeId = new Map<string, Ownership>();
-    const resolveOwnership = async (node: T): Promise<Ownership> => {
+    for (const node of batch.nodes) {
       const path: T[] = [];
       const visiting = new Set<string>();
       let current: T | undefined = node;
       let ownership: Ownership = { frameId: batch.frame.frameId, strength: 1 };
       while (current) {
-        if (work++ % 256 === 0) await captureCheckpoint(signal);
+        if (work++ % 256 === 0) {
+          const pending = checkpoint();
+          if (pending) await pending;
+        }
         const cached = ownershipByNodeId.get(current.nodeId);
         if (cached) {
           ownership = cached;
@@ -137,17 +148,14 @@ export async function buildFrameDocuments<T extends FrameOwnedAxNode>(
         current = current.parentId ? nodeById.get(current.parentId) : undefined;
       }
       for (let i = path.length - 1; i >= 0; i--) {
-        if (work++ % 256 === 0) await captureCheckpoint(signal);
+        if (work++ % 256 === 0) {
+          const pending = checkpoint();
+          if (pending) await pending;
+        }
         ownership = { frameId: ownership.frameId, strength: Math.min(2, ownership.strength) };
         ownershipByNodeId.set(path[i].nodeId, ownership);
       }
       if (!ownershipByNodeId.has(node.nodeId)) ownershipByNodeId.set(node.nodeId, ownership);
-      return ownership;
-    };
-
-    for (const node of batch.nodes) {
-      if (work++ % 256 === 0) await captureCheckpoint(signal);
-      const ownership = await resolveOwnership(node);
       if (!ownership.frameId) continue;
       const key = targetNodeKey(batch.frame.target, node.nodeId);
       const existing = candidates.get(key);
@@ -162,7 +170,10 @@ export async function buildFrameDocuments<T extends FrameOwnedAxNode>(
   );
   const axNodesByFrame = new Map<string, T[]>();
   for (const candidate of candidates.values()) {
-    if (work++ % 256 === 0) await captureCheckpoint(signal);
+    if (work++ % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
     const { node, target, ownership } = candidate;
     const parentFrameId = node.parentId
       ? ownershipByTargetNode.get(targetNodeKey(target, node.parentId))
@@ -188,5 +199,6 @@ export async function buildFrameDocuments<T extends FrameOwnedAxNode>(
     contextScopeId: frame.frameId,
     axNodes: axNodesByFrame.get(frame.frameId) ?? [],
     domNodes: domNodesForFrame(frame.frameId),
+    excludedBackendNodeIds: captured.frameExcludedBackendNodeIds?.get(frame.frameId),
   }));
 }

apps/extension/src/tools/vom/normalize.ts

@@ -4,19 +4,21 @@ import { type GeometryProjection, projectRectToViewport } from "../geometry";
 import {
   type FrameProjectionState,
   projectSnapshotRect,
+  type SnapshotCoordinates,
+  snapshotCoordinates,
   snapshotViewportRect,
 } from "../geometry/coordinate-types";
-import { cssViewport, GeometryContext } from "../geometry/frame-context";
-import type { CapturedNode } from "./facts";
 import {
-  buildDocumentIndex,
-  type CaptureIssue,
-  captureCheckpoint,
-  type DocumentIndex,
-  isCaptureAbort,
-  type NodeFacts,
-  throwCaptureAborted,
-} from "./facts";
+  GeometryContext,
+  type LayoutMetrics,
+  snapshotLayoutScale,
+} from "../geometry/frame-context";
+import {
+  createCaptureCheckpoint,
+  isAbortError as isCaptureAbort,
+  throwIfAborted as throwCaptureAborted,
+} from "./capture-abort";
+import { buildDocumentIndex, type CaptureIssue, type DocumentIndex, type NodeFacts } from "./facts";
 import {
   decodeDocument,
   type SnapshotDocument,
@@ -24,10 +26,90 @@ import {
   snapshotFrameId,
 } from "./snapshot";
 
+export interface FrameContext {
+  frameId?: string;
+  ownerFrameBackendNodeId: number | null;
+  projection: FrameProjectionState | null;
+  targetProjection?: GeometryProjection | null;
+  target: CdpTarget;
+  coordinates: SnapshotCoordinates | null;
+}
+
 export interface NormalizedDocument {
+  nodes: NodeFacts[];
   index: DocumentIndex;
+  documentElementBackendNodeId?: number;
+}
+
+/** Interpret one document using a supplied projection. No live reads or frame scheduling. */
+export async function normalizeDocument(
+  doc: SnapshotDocument,
+  strings: string[],
+  context: FrameContext,
+  signal?: AbortSignal,
+): Promise<NormalizedDocument> {
+  const decoded = await decodeDocument(doc, strings, signal);
+  const checkpoint = createCaptureCheckpoint(signal);
+  const nodes: NodeFacts[] = [];
+  for (let i = 0; i < decoded.nodes.length; i++) {
+    if (i % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
+    const node = decoded.nodes[i];
+    const bounds = node.layout?.bounds ?? [];
+    const input = snapshotViewportRect(
+      bounds,
+      { target: context.target, frameId: context.frameId },
+      context.coordinates,
+    );
+    const local = input?.rect;
+    let rect =
+      input && context.projection?.status === "available"
+        ? projectSnapshotRect(input, context.projection.projection)
+        : null;
+    if (rect && context.targetProjection !== undefined)
+      rect = context.targetProjection
+        ? projectRectToViewport(
+            { x: rect.x, y: rect.y, w: rect.width, h: rect.height },
+            context.targetProjection,
+          )
+        : null;
+    const visibility = node.layout?.styles.visibility || "visible";
+    const opacity = node.layout?.styles.opacity || "1";
+    nodes.push({
+      ...node,
+      ...(context.frameId ? { frameId: context.frameId } : {}),
+      ownerFrameBackendNodeId: context.ownerFrameBackendNodeId,
+      localRect: local ? { x: local.x, y: local.y, w: local.width, h: local.height } : null,
+      rect: rect ? { x: rect.x, y: rect.y, w: rect.width, h: rect.height } : null,
+      rendered:
+        bounds.length >= 4 &&
+        bounds.slice(0, 4).every(Number.isFinite) &&
+        bounds[2] > 0 &&
+        bounds[3] > 0 &&
+        visibility !== "hidden" &&
+        visibility !== "collapse" &&
+        (Number.parseFloat(opacity) || 0) > 0,
+    });
+  }
+  const index = await buildDocumentIndex(nodes, signal);
+  return {
+    nodes: nodes.filter(
+      (node) => !node.tag.startsWith("#") && !index.excludedBackendNodeIds.has(node.backendNodeId),
+    ),
+    index,
+    documentElementBackendNodeId: nodes.find(
+      (node) =>
+        node.nodeType === 1 &&
+        node.parentBackendNodeId !== null &&
+        index.nodes.get(node.parentBackendNodeId)?.nodeType === 9,
+    )?.backendNodeId,
+  };
+}
+
+export interface NormalizedFrameDocument extends NormalizedDocument {
   frame: CdpFrame;
-  domNodes: CapturedNode[];
 }
 
 /** One target's snapshot. Source ownership is checked before interpreting any
@@ -40,9 +122,17 @@ export async function normalizeSnapshot(
   issues: CaptureIssue[],
   signal?: AbortSignal,
   rootFrameId?: string,
-): Promise<NormalizedDocument[]> {
+): Promise<NormalizedFrameDocument[]> {
   const strings = snapshot.strings ?? [];
   const raw = snapshot.documents ?? [];
+  const ownerIds = new Set<number>();
+  for (const document of raw) {
+    for (const index of document.nodes?.contentDocumentIndex?.index ?? []) {
+      const id = document.nodes?.backendNodeId?.[index];
+      if (id !== undefined) ownerIds.add(id);
+    }
+  }
+  geometry.registerSnapshotOwners(target, ownerIds);
   const frameById = new Map(frames.map((frame) => [frame.frameId, frame]));
   const sources = new Map<string, SnapshotDocument>();
   for (const doc of raw) {
@@ -58,17 +148,20 @@ export async function normalizeSnapshot(
     }
     sources.set(id, doc);
   }
-  let viewport: Viewport = { width: 0, height: 0 };
-  let scrollX = 0,
-    scrollY = 0;
+  let metrics: LayoutMetrics = {};
   try {
-    const measured = cssViewport(await geometry.layoutMetrics(target));
-    viewport = { width: measured.width, height: measured.height };
-    scrollX = measured.scrollX;
-    scrollY = measured.scrollY;
+    metrics = await geometry.layoutMetrics(target);
   } catch (error) {
     if (isCaptureAbort(error)) throw error;
   }
+  const viewport: Viewport = {
+    width: metrics.cssLayoutViewport?.clientWidth ?? 0,
+    height: metrics.cssLayoutViewport?.clientHeight ?? 0,
+  };
+  const layoutUnitsPerCssPixel = snapshotLayoutScale(metrics);
+  const viewportAvailable = [viewport.width, viewport.height].every(
+    (size) => Number.isFinite(size) && size > 0,
+  );
 
   const children = new Map<string, CdpFrame[]>();
   const pending: CdpFrame[] = [];
@@ -81,7 +174,7 @@ export async function normalizeSnapshot(
     }
   }
   const projections = new Map<string, FrameProjectionState | null>();
-  const result: NormalizedDocument[] = [];
+  const result: NormalizedFrameDocument[] = [];
   let targetProjection: GeometryProjection | null = null;
   const targetRoot = rootFrameId ? frameById.get(rootFrameId) : undefined;
   if (target.sessionId && targetRoot) {
@@ -93,6 +186,7 @@ export async function normalizeSnapshot(
       if (isCaptureAbort(error)) throw error;
     }
   }
+  const checkpoint = createCaptureCheckpoint(signal);
   const visited = new Set<string>();
   const remaining = frames[Symbol.iterator]();
   for (let cursor = 0; visited.size < frames.length; cursor++) {
@@ -102,7 +196,10 @@ export async function normalizeSnapshot(
       if (next.done) break;
       pending.push(next.value);
     }
-    if (cursor % 256 === 0) await captureCheckpoint(signal);
+    if (cursor % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
     const frame = pending[cursor];
     if (visited.has(frame.frameId)) continue;
     visited.add(frame.frameId);
@@ -110,12 +207,24 @@ export async function normalizeSnapshot(
     const doc = sources.get(frame.frameId);
     if (!doc) continue;
     const source = { target, frameId: frame.frameId };
-    const state: FrameProjectionState | null =
+    const coordinates = snapshotCoordinates(
+      doc,
+      layoutUnitsPerCssPixel,
       frame.frameId === rootFrameId
-        ? {
-            status: "available",
-            projection: { source, geometry: { sourceClips: [], edges: [], topViewport: viewport } },
-          }
+        ? { x: metrics.cssLayoutViewport?.pageX, y: metrics.cssLayoutViewport?.pageY }
+        : undefined,
+    );
+    let state: FrameProjectionState | null =
+      frame.frameId === rootFrameId
+        ? viewportAvailable && coordinates
+          ? {
+              status: "available",
+              projection: {
+                source,
+                geometry: { sourceClips: [], edges: [], topViewport: viewport },
+              },
+            }
+          : { status: "unavailable", source, reason: "snapshot-coordinates-unavailable" }
         : (projections.get(frame.frameId) ?? null);
     if (!state && frame.frameId !== rootFrameId)
       issues.push({
@@ -124,6 +233,8 @@ export async function normalizeSnapshot(
         stage: "ownership",
         reason: "frame-ownership-unresolved",
       });
+    if (!coordinates && (!state || state.status === "available"))
+      state = { status: "unavailable", source, reason: "snapshot-coordinates-unavailable" };
     projections.set(frame.frameId, state);
     const projection = state?.status === "available" ? state.projection : null;
     if (!projection || (target.sessionId && !targetProjection))
@@ -168,6 +279,14 @@ export async function normalizeSnapshot(
             projections.set(child.frameId, null);
             continue;
           }
+          if (!snapshotCoordinates(sources.get(child.frameId)!, layoutUnitsPerCssPixel)) {
+            projections.set(child.frameId, {
+              status: "unavailable",
+              source: childSource,
+              reason: "snapshot-coordinates-unavailable",
+            });
+            continue;
+          }
           try {
             projections.set(
               child.frameId,
@@ -187,47 +306,20 @@ export async function normalizeSnapshot(
     // Join active reads and their cleanup before returning cancellation.
     if (failure) throw failure;
     throwCaptureAborted(signal);
-    const decoded = await decodeDocument(doc, strings, signal);
-    const nodes: NodeFacts[] = [];
-    for (let i = 0; i < decoded.nodes.length; i++) {
-      if (i % 256 === 0) await captureCheckpoint(signal);
-      const node = decoded.nodes[i];
-      const input = snapshotViewportRect(node.layout?.bounds ?? [], source, {
-        x: doc.scrollOffsetX ?? (frame.frameId === rootFrameId ? scrollX : 0),
-        y: doc.scrollOffsetY ?? (frame.frameId === rootFrameId ? scrollY : 0),
-      });
-      const local = input?.rect;
-      let rect = input && projection ? projectSnapshotRect(input, projection) : null;
-      if (rect && target.sessionId)
-        rect = targetProjection
-          ? projectRectToViewport(
-              { x: rect.x, y: rect.y, w: rect.width, h: rect.height },
-              targetProjection,
-            )
-          : null;
-      const styles = node.layout?.styles;
-      const visibility = styles?.visibility || "visible";
-      const opacity = styles?.opacity || "1";
-      nodes.push({
-        ...node,
+    const normalized = await normalizeDocument(
+      doc,
+      strings,
+      {
         frameId: frame.frameId,
         ownerFrameBackendNodeId: frame.ownerBackendNodeId ?? null,
-        localRect: local ? { x: local.x, y: local.y, w: local.width, h: local.height } : null,
-        rect: rect ? { x: rect.x, y: rect.y, w: rect.width, h: rect.height } : null,
-        rendered:
-          !!local &&
-          visibility !== "hidden" &&
-          visibility !== "collapse" &&
-          (Number.parseFloat(opacity) || 0) > 0,
-      });
-    }
-    const index = await buildDocumentIndex(nodes, signal);
-    const domNodes = nodes.filter((node) => !node.tag.startsWith("#"));
-    result.push({
-      index,
-      frame,
-      domNodes,
-    });
+        projection: state,
+        target,
+        ...(target.sessionId ? { targetProjection } : {}),
+        coordinates,
+      },
+      signal,
+    );
+    result.push({ ...normalized, frame });
   }
   return result;
 }

apps/extension/src/tools/vom/snapshot.ts

@@ -1,6 +1,7 @@
 import { type CdpFrame, type CdpTarget, cdpTargetKey } from "@/browser-driver/frame-graph";
-import type { CapturedNode } from "./facts";
-import { captureCheckpoint, type DecodedDocument, type DecodedNode } from "./facts";
+import { createCaptureCheckpoint } from "./capture-abort";
+import type { CapturedNode } from "./capture-types";
+import type { DecodedDocument, DecodedNode } from "./facts";
 export const REQUESTED_STYLES = [
   "position",
   "pointer-events",
@@ -87,7 +88,7 @@ function str(strings: string[], idx: number | undefined): string {
   return strings[idx] ?? "";
 }
 
-function sparseIndexMap(sparse: SparseArray | undefined): Map<number, number> {
+export function sparseIndexMap(sparse: SparseArray | undefined): Map<number, number> {
   const out = new Map<number, number>();
   if (!sparse?.index || !sparse.value) return out;
   for (let i = 0; i < sparse.index.length; i++) {
@@ -103,6 +104,7 @@ export async function decodeDocument(
   strings: string[],
   signal?: AbortSignal,
 ): Promise<DecodedDocument> {
+  const checkpoint = createCaptureCheckpoint(signal);
   const dn = doc.nodes;
   const dl = doc.layout;
   if (!dn?.backendNodeId) {
@@ -112,7 +114,10 @@ export async function decodeDocument(
   const count = dn.backendNodeId.length;
   const layoutByNode = new Map<number, number>();
   for (let i = 0; i < (dl?.nodeIndex?.length ?? 0); i++) {
-    if (i % 256 === 0) await captureCheckpoint(signal);
+    if (i % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
     layoutByNode.set(dl!.nodeIndex![i], i);
   }
 
@@ -127,7 +132,10 @@ export async function decodeDocument(
   const nodeTextContent = new Map<number, string[]>();
   if (dn.nodeValue) {
     for (let n = 0; n < count; n++) {
-      if (n % 256 === 0) await captureCheckpoint(signal);
+      if (n % 256 === 0) {
+        const pending = checkpoint();
+        if (pending) await pending;
+      }
       const nvIdx = dn.nodeValue[n] ?? -1;
       if (nvIdx < 0) continue;
       const text = str(strings, nvIdx).trim();
@@ -144,7 +152,10 @@ export async function decodeDocument(
   // Decode fields without assigning a coordinate projection or semantic policy.
   const nodes: DecodedNode[] = [];
   for (let n = 0; n < count; n++) {
-    if (n % 256 === 0) await captureCheckpoint(signal);
+    if (n % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
     const backendNodeId = dn.backendNodeId[n];
     const parentIdx = dn.parentIndex?.[n] ?? -1;
     const parentBackendNodeId = parentIdx >= 0 ? (dn.backendNodeId[parentIdx] ?? null) : null;
@@ -164,7 +175,7 @@ export async function decodeDocument(
       li === undefined
         ? undefined
         : {
-            boundsSpace: "snapshot-document-css" as const,
+            boundsSpace: "snapshot-document-layout" as const,
             bounds: dl?.bounds?.[li],
             styles,
           };

crates/bsk-cli/src/cli/business_rpc.rs

@@ -73,6 +73,14 @@ where
     P: Serialize + Send + 'static,
     R: DeserializeOwned + Send + 'static,
 {
+    let parent_cancel = stdin_cancellation();
+    if parent_cancel.as_ref().is_some_and(|rx| *rx.borrow()) {
+        return Err(CliError::from_rpc(RpcError {
+            code: ErrorCode::Cancelled,
+            message: "parent closed the cancellation pipe".into(),
+            data: Some(serde_json::json!({"reason": "cancelled_before_dispatch"})),
+        }));
+    }
     let rpc_id: RpcId = format!("{}-{}", rpc_id_prefix, random_short_id());
     let mut client = IpcClient::connect(sock.clone()).await?;
     let rpc_id_for_call = rpc_id.clone();
@@ -88,16 +96,16 @@ where
     let outcome = tokio::select! {
         biased;
         res = &mut main_fut => res?,
-        sig = wait_for_sigint() => {
-            sig.context("install SIGINT handler").map_err(CliError::Local)?;
-            debug!(rpc_id = %rpc_id_for_cancel, "SIGINT: forwarding cancel to daemon");
+        sig = wait_for_cancel(parent_cancel) => {
+            sig.context("wait for cancellation").map_err(CliError::Local)?;
+            debug!(rpc_id = %rpc_id_for_cancel, "forwarding cancel to daemon");
             let _ = send_cancel(&sock, &rpc_id_for_cancel).await;
             match tokio::time::timeout(CANCEL_RESPONSE_GRACE, &mut main_fut).await {
                 Ok(res) => res?,
                 Err(_) => {
                     debug!(
                         rpc_id = %rpc_id_for_cancel,
-                        "SIGINT: cancel grace elapsed; synthesising cancelled error"
+                        "cancel grace elapsed; synthesising cancelled error"
                     );
                     return Err(CliError::from_rpc(RpcError {
                         code: ErrorCode::Cancelled,
@@ -112,6 +120,46 @@ where
     outcome.map_err(CliError::from_rpc)
 }
 
+/// Release caller-owned staging even after cancellation. This deliberately
+/// exposes only transfer.release, not a general bypass for business RPCs.
+/// The entire batch, including connection setup, shares one bounded budget.
+pub fn release_transfers<'a>(
+    sock: &Path,
+    transfer_ids: impl IntoIterator<Item = &'a str>,
+) -> Result<(), CliError> {
+    use bsk_protocol::tools::{TransferIdParams, TransferReleaseResult};
+    const CLEANUP_TIMEOUT: Duration = Duration::from_secs(5);
+    let ids: Vec<_> = transfer_ids.into_iter().collect();
+    if ids.is_empty() {
+        return Ok(());
+    }
+    let rt = tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .context("build runtime for transfer cleanup")?;
+    rt.block_on(async {
+        tokio::time::timeout(CLEANUP_TIMEOUT, async {
+            let mut client = IpcClient::connect(sock).await?;
+            for id in ids {
+                client
+                    .call::<_, TransferReleaseResult>(
+                        "transfer-release",
+                        Method::TransferRelease,
+                        Some(TransferIdParams {
+                            transfer_id: id.to_string(),
+                        }),
+                        CLEANUP_TIMEOUT,
+                    )
+                    .await?
+                    .map_err(CliError::from_rpc)?;
+            }
+            Ok::<_, CliError>(())
+        })
+        .await
+        .context("transfer cleanup exceeded its total time budget")?
+    })
+}
+
 /// Send a `cancel { rpc_id }` frame over a fresh connection so it
 /// lands on the daemon while the original call is still parked.
 ///
@@ -146,8 +194,57 @@ fn random_short_id() -> String {
     bytes.iter().map(|b| format!("{b:02x}")).collect()
 }
 
-/// Wait for either Ctrl-C or process SIGTERM. Returning here means
-/// the user has asked us to stop.
+/// Opt-in control pipe for parent processes that cannot send Ctrl-C (Node on
+/// Windows). One reader survives the short-lived runtimes used by multi-RPC
+/// commands such as upload. Ordinary CLI stdin and terminal Ctrl-C are unchanged.
+fn stdin_cancellation() -> Option<tokio::sync::watch::Receiver<bool>> {
+    if std::env::var("BSK_CANCEL_ON_STDIN_CLOSE").as_deref() != Ok("1") {
+        return None;
+    }
+    static CANCEL: std::sync::OnceLock<tokio::sync::watch::Receiver<bool>> =
+        std::sync::OnceLock::new();
+    Some(
+        CANCEL
+            .get_or_init(|| {
+                let (tx, rx) = tokio::sync::watch::channel(false);
+                std::thread::spawn(move || {
+                    use std::io::Read;
+                    let mut stdin = std::io::stdin().lock();
+                    let mut buf = [0; 64];
+                    loop {
+                        match stdin.read(&mut buf) {
+                            Ok(0) => break,
+                            Ok(_) => {}
+                            Err(err) if err.kind() == std::io::ErrorKind::Interrupted => continue,
+                            Err(_) => break,
+                        }
+                    }
+                    let _ = tx.send(true);
+                });
+                rx
+            })
+            .clone(),
+    )
+}
+
+async fn wait_for_cancel(
+    parent_cancel: Option<tokio::sync::watch::Receiver<bool>>,
+) -> anyhow::Result<()> {
+    let parent_closed = async move {
+        match parent_cancel {
+            Some(mut rx) => {
+                let _ = rx.wait_for(|closed| *closed).await;
+            }
+            None => std::future::pending::<()>().await,
+        }
+    };
+    tokio::select! {
+        result = wait_for_sigint() => result,
+        _ = parent_closed => Ok(()),
+    }
+}
+
+/// Wait for terminal Ctrl-C.
 async fn wait_for_sigint() -> anyhow::Result<()> {
     tokio::signal::ctrl_c().await.context("listen for SIGINT")?;
     Ok(())

crates/bsk-cli/src/cli/download.rs

@@ -9,8 +9,7 @@ use anyhow::Context;
 use base64::Engine;
 use bsk_protocol::Method;
 use bsk_protocol::tools::{
-    DownloadParams, DownloadResult, TransferChunkParams, TransferChunkResult, TransferIdParams,
-    TransferReleaseResult,
+    DownloadParams, DownloadResult, TransferChunkParams, TransferChunkResult,
 };
 use clap::Args;
 use uuid::Uuid;
@@ -70,13 +69,7 @@ pub fn dispatch(args: DownloadArgs, format: Format) -> Result<(), CliError> {
         CliError::Local(anyhow::anyhow!("daemon returned no download transfer id"))
     })?;
     let write_result = write_transfer(&info.sock_path, &transfer_id, &args.out, args.overwrite);
-    let _: Result<TransferReleaseResult, CliError> = crate::cli::business_rpc::call(
-        info.sock_path,
-        "transfer-release",
-        Method::TransferRelease,
-        Some(TransferIdParams { transfer_id }),
-        Duration::from_secs(5),
-    );
+    let _ = crate::cli::business_rpc::release_transfers(&info.sock_path, [transfer_id.as_str()]);
     write_result?;
     match format {
         Format::Json => {

crates/bsk-cli/src/cli/upload.rs

@@ -10,8 +10,7 @@ use base64::Engine;
 use bsk_protocol::Method;
 use bsk_protocol::tools::{
     TransferBeginParams, TransferBeginResult, TransferChunkParams, TransferChunkResult,
-    TransferIdParams, TransferReadyResult, TransferReleaseResult, UploadFile, UploadMode,
-    UploadParams, UploadResult,
+    TransferIdParams, TransferReadyResult, UploadFile, UploadMode, UploadParams, UploadResult,
 };
 use clap::{Args, ValueEnum};
 
@@ -69,14 +68,12 @@ pub fn dispatch(args: UploadArgs, format: Format) -> Result<(), CliError> {
     let (ref_, selector) = split_target(args.target, args.ref_, args.selector)?;
     let mut staged = Vec::new();
     for path in &args.files {
-        match stage_file(&info.sock_path, &args.session, path) {
-            Ok(file) => staged.push(file),
-            Err(err) => {
-                for (id, _) in &staged {
-                    let _ = release(&info.sock_path, id);
-                }
-                return Err(err);
-            }
+        if let Err(err) = stage_file(&info.sock_path, &args.session, path, &mut staged) {
+            let _ = crate::cli::business_rpc::release_transfers(
+                &info.sock_path,
+                staged.iter().map(|(id, _)| id.as_str()),
+            );
+            return Err(err);
         }
     }
     let params = UploadParams {
@@ -102,6 +99,17 @@ pub fn dispatch(args: UploadArgs, format: Format) -> Result<(), CliError> {
         Some(params),
         ipc_timeout(args.timeout),
     );
+    // The helper can reject cancellation before handing any request to the
+    // daemon. In that case staging still belongs to this CLI.
+    if result.as_ref().is_err_and(|err| {
+        err.data()
+            .is_some_and(|data| data["reason"] == "cancelled_before_dispatch")
+    }) {
+        let _ = crate::cli::business_rpc::release_transfers(
+            &info.sock_path,
+            staged.iter().map(|(id, _)| id.as_str()),
+        );
+    }
     // Once tool.upload is dispatched, staging ownership belongs to the
     // session. A transport timeout cannot prove that Chrome did not attach
     // the file, so releasing here could invalidate a late successful attach.
@@ -118,7 +126,12 @@ pub fn dispatch(args: UploadArgs, format: Format) -> Result<(), CliError> {
     Ok(())
 }
 
-fn stage_file(sock: &Path, session: &str, path: &PathBuf) -> Result<(String, String), CliError> {
+fn stage_file(
+    sock: &Path,
+    session: &str,
+    path: &PathBuf,
+    staged: &mut Vec<(String, String)>,
+) -> Result<(), CliError> {
     let mut file = File::open(path)
         .with_context(|| format!("open upload file {}", path.display()))
         .map_err(CliError::Local)?;
@@ -149,55 +162,39 @@ fn stage_file(sock: &Path, session: &str, path: &PathBuf) -> Result<(String, Str
         }),
         Duration::from_secs(10),
     )?;
-    let staged = (|| {
-        let mut offset = 0u64;
-        let mut buf = vec![0u8; begin.chunk_size as usize];
-        loop {
-            let n = file.read(&mut buf).map_err(|e| CliError::Local(e.into()))?;
-            if n == 0 {
-                break;
-            }
-            let reply: TransferChunkResult = crate::cli::business_rpc::call(
-                sock.to_path_buf(),
-                "transfer-chunk",
-                Method::TransferChunk,
-                Some(TransferChunkParams {
-                    transfer_id: begin.transfer_id.clone(),
-                    offset,
-                    data_base64: base64::engine::general_purpose::STANDARD.encode(&buf[..n]),
-                }),
-                Duration::from_secs(30),
-            )?;
-            offset = reply.next_offset;
+    // Record ownership immediately so one error path releases both completed
+    // files and the current partially staged file.
+    staged.push((begin.transfer_id.clone(), name));
+    let mut offset = 0u64;
+    let mut buf = vec![0u8; begin.chunk_size as usize];
+    loop {
+        let n = file.read(&mut buf).map_err(|e| CliError::Local(e.into()))?;
+        if n == 0 {
+            break;
         }
-        let _: TransferReadyResult = crate::cli::business_rpc::call(
+        let reply: TransferChunkResult = crate::cli::business_rpc::call(
             sock.to_path_buf(),
-            "transfer-finish",
-            Method::TransferFinish,
-            Some(TransferIdParams {
+            "transfer-chunk",
+            Method::TransferChunk,
+            Some(TransferChunkParams {
                 transfer_id: begin.transfer_id.clone(),
+                offset,
+                data_base64: base64::engine::general_purpose::STANDARD.encode(&buf[..n]),
             }),
-            Duration::from_secs(10),
+            Duration::from_secs(30),
         )?;
-        Ok::<_, CliError>(())
-    })();
-    if let Err(err) = staged {
-        let _ = release(sock, &begin.transfer_id);
-        return Err(err);
+        offset = reply.next_offset;
     }
-    Ok((begin.transfer_id, name))
-}
-
-fn release(sock: &Path, id: &str) -> Result<TransferReleaseResult, CliError> {
-    crate::cli::business_rpc::call(
+    let _: TransferReadyResult = crate::cli::business_rpc::call(
         sock.to_path_buf(),
-        "transfer-release",
-        Method::TransferRelease,
+        "transfer-finish",
+        Method::TransferFinish,
         Some(TransferIdParams {
-            transfer_id: id.to_string(),
+            transfer_id: begin.transfer_id.clone(),
         }),
-        Duration::from_secs(5),
-    )
+        Duration::from_secs(10),
+    )?;
+    Ok(())
 }
 
 fn ipc_timeout(timeout_ms: u32) -> Duration {

crates/bsk-cli/tests/windows_parent_cancel.rs

@@ -0,0 +1,342 @@
+//! Real Windows CLI cancellation, including caller-owned transfer cleanup.
+#![cfg(windows)]
+
+use std::path::Path;
+use std::sync::{Arc, Mutex};
+use std::time::{Duration, Instant};
+
+use bsk::daemon::{file_transfer::TransferRegistry, info::DaemonInfo};
+use bsk_protocol::tools::{TransferBeginParams, TransferIdParams};
+use bsk_protocol::{ErrorCode, Frame, Method, ResponseBody, ResponseFrame, RpcError};
+use serde_json::json;
+use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
+use tokio::net::windows::named_pipe::ServerOptions;
+use tokio::process::Command;
+use tokio::sync::{Notify, watch};
+
+fn response<T: serde::Serialize>(result: Result<T, RpcError>) -> ResponseBody {
+    match result {
+        Ok(value) => ResponseBody::Ok(serde_json::to_value(value).unwrap()),
+        Err(err) => ResponseBody::Err(err),
+    }
+}
+
+#[test]
+fn stdin_close_cancels_business_but_releases_resources_with_a_bounded_budget() {
+    // Resolve the production registry's root before starting any runtime threads.
+    let registry_home = tempfile::tempdir().unwrap();
+    let original_home = std::env::var_os("BSK_HOME");
+    unsafe {
+        std::env::set_var("BSK_HOME", registry_home.path());
+    }
+    let transfers = Arc::new(TransferRegistry::new().unwrap());
+    unsafe {
+        match original_home {
+            Some(value) => std::env::set_var("BSK_HOME", value),
+            None => std::env::remove_var("BSK_HOME"),
+        }
+    }
+    transfers.initialize().unwrap();
+    tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .unwrap()
+        .block_on(exercise(
+            transfers,
+            &registry_home.path().join("run/transfers"),
+        ));
+}
+
+async fn exercise(transfers: Arc<TransferRegistry>, staging_root: &Path) {
+    for mode in [
+        "wait",
+        "upload",
+        "upload-multi",
+        "upload-before-dispatch",
+        "download",
+        "upload-multi-stall",
+        "ordinary",
+    ] {
+        let home = tempfile::tempdir().unwrap();
+        let pipe_name = format!(r"\\.\pipe\bsk-parent-cancel-{}", uuid::Uuid::new_v4());
+        let info = DaemonInfo::now(std::process::id(), (&pipe_name).into(), 0, "0.2.0");
+        std::fs::write(
+            home.path().join("daemon.json"),
+            serde_json::to_vec(&info).unwrap(),
+        )
+        .unwrap();
+        let mut pipe = ServerOptions::new()
+            .first_pipe_instance(true)
+            .create(&pipe_name)
+            .unwrap();
+        let registered = Arc::new(Notify::new());
+        let pending = Arc::new(Mutex::new(None::<String>));
+        let ids = Arc::new(Mutex::new(Vec::<String>::new()));
+        let released = Arc::new(Mutex::new(Vec::<String>::new()));
+        let received = Arc::new(Mutex::new(Vec::<Method>::new()));
+        let download_id = if mode == "download" {
+            let staging = transfers.begin_download("fixture").unwrap();
+            let browser_dir = home.path().join("BrowserSkill").join(&staging.transfer_id);
+            std::fs::create_dir_all(&browser_dir).unwrap();
+            let file = browser_dir.join("download.txt");
+            std::fs::write(&file, b"download fixture").unwrap();
+            transfers
+                .import_download(&staging.transfer_id, &file)
+                .unwrap();
+            ids.lock().unwrap().push(staging.transfer_id.clone());
+            Some(staging.transfer_id)
+        } else {
+            None
+        };
+        let (cancel, cancelled) = watch::channel(false);
+        let ready = Arc::clone(&registered);
+        let name = pipe_name.clone();
+        let registry = Arc::clone(&transfers);
+        let server_ids = Arc::clone(&ids);
+        let server_released = Arc::clone(&released);
+        let server_received = Arc::clone(&received);
+        let server = tokio::spawn(async move {
+            let mut connections = tokio::task::JoinSet::new();
+            loop {
+                pipe.connect().await.unwrap();
+                let next = ServerOptions::new().create(&name).unwrap();
+                let connection = std::mem::replace(&mut pipe, next);
+                let ready = Arc::clone(&ready);
+                let pending = Arc::clone(&pending);
+                let cancel = cancel.clone();
+                let mut cancelled = cancelled.clone();
+                let name = name.clone();
+                let registry = Arc::clone(&registry);
+                let ids = Arc::clone(&server_ids);
+                let released = Arc::clone(&server_released);
+                let received = Arc::clone(&server_received);
+                let download_id = download_id.clone();
+                connections.spawn(async move {
+                    let (read, mut write) = tokio::io::split(connection);
+                    let mut reader = BufReader::new(read);
+                    let mut line = String::new();
+                    while reader.read_line(&mut line).await.unwrap_or(0) > 0 {
+                        let Frame::Request(req) = serde_json::from_str::<Frame>(&line).unwrap()
+                        else {
+                            panic!("expected request");
+                        };
+                        line.clear();
+                        received.lock().unwrap().push(req.method.clone());
+                        let params = req.params.clone().unwrap_or_default();
+                        let body = match req.method {
+                            Method::SystemStatus => ResponseBody::Ok(json!({
+                                "daemon_version": "0.2.0", "protocol_version": "1.1",
+                                "pid": std::process::id(), "uptime_secs": 0,
+                                "ws_port": 0, "sock_path": name,
+                                "browsers": [], "sessions": [], "version_skew_browsers": []
+                            })),
+                            Method::TransferBegin => {
+                                let begin = registry
+                                    .begin_upload(serde_json::from_value(params).unwrap())
+                                    .unwrap();
+                                ids.lock().unwrap().push(begin.transfer_id.clone());
+                                response(Ok(begin))
+                            }
+                            Method::ToolDownload => ResponseBody::Ok(json!({
+                                "tab_id": 1, "suggested_filename": "download.txt",
+                                "byte_size": 16, "transfer_id": download_id,
+                            })),
+                            Method::ToolWaitMs if mode == "ordinary" => {
+                                ResponseBody::Ok(json!({"waited_ms": 1}))
+                            }
+                            Method::TransferChunk
+                                if mode == "upload-before-dispatch"
+                                    || (mode.contains("multi")
+                                        && ids.lock().unwrap().len() == 1) =>
+                            {
+                                response(
+                                    registry.write_chunk(serde_json::from_value(params).unwrap()),
+                                )
+                            }
+                            Method::TransferFinish if mode != "upload-before-dispatch" => response(
+                                registry.finish_upload(serde_json::from_value(params).unwrap()),
+                            ),
+                            Method::ToolWaitMs
+                            | Method::TransferChunk
+                            | Method::TransferRead
+                            | Method::TransferFinish => {
+                                *pending.lock().unwrap() = Some(req.id.clone());
+                                ready.notify_one();
+                                cancelled.wait_for(|value| *value).await.unwrap();
+                                if mode == "upload-before-dispatch" {
+                                    // Finish won the race with cancellation, but tool.upload must
+                                    // not be dispatched and the CLI still owns the staging.
+                                    response(
+                                        registry
+                                            .finish_upload(serde_json::from_value(params).unwrap()),
+                                    )
+                                } else {
+                                    ResponseBody::Err(RpcError {
+                                        code: ErrorCode::Cancelled,
+                                        message: "parent cancellation reached daemon".into(),
+                                        data: None,
+                                    })
+                                }
+                            }
+                            Method::Cancel => {
+                                let target = params["rpc_id"].as_str().unwrap();
+                                assert_eq!(pending.lock().unwrap().as_deref(), Some(target));
+                                cancel.send(true).unwrap();
+                                ResponseBody::Ok(json!({"cancelled": true}))
+                            }
+                            Method::TransferRelease => {
+                                let params: TransferIdParams =
+                                    serde_json::from_value(params).unwrap();
+                                released.lock().unwrap().push(params.transfer_id.clone());
+                                if mode.contains("stall") {
+                                    std::future::pending::<()>().await;
+                                }
+                                response(Ok(registry.release(params)))
+                            }
+                            other => panic!("unexpected request after cancellation: {other:?}"),
+                        };
+                        let response = Frame::Response(ResponseFrame { id: req.id, body });
+                        let mut bytes = serde_json::to_vec(&response).unwrap();
+                        bytes.push(b'\n');
+                        if write.write_all(&bytes).await.is_err() {
+                            break;
+                        }
+                    }
+                });
+            }
+        });
+
+        let mut cmd = Command::new(env!("CARGO_BIN_EXE_bsk"));
+        cmd.env("BSK_HOME", home.path())
+            .env("BSK_AUTO_UPDATE", "off")
+            .env_remove("BSK_CANCEL_ON_STDIN_CLOSE")
+            .stdout(std::process::Stdio::piped())
+            .stderr(std::process::Stdio::piped())
+            .creation_flags(0x0800_0000)
+            .kill_on_drop(true);
+        if mode.starts_with("upload") {
+            let source = home.path().join("upload.txt");
+            // Declare 300 MiB without allocating or transferring that much data.
+            std::fs::File::create(&source)
+                .unwrap()
+                .set_len(if mode == "upload-before-dispatch" {
+                    16
+                } else {
+                    300 * 1024 * 1024
+                })
+                .unwrap();
+            cmd.args(["upload", "--session", "fixture", "--selector", "input"]);
+            if mode.contains("multi") {
+                let first = home.path().join("first.txt");
+                std::fs::write(&first, b"first file").unwrap();
+                cmd.arg("--file").arg(first);
+            }
+            cmd.arg("--file").arg(source);
+        } else if mode == "download" {
+            let out = home.path().join("out.txt");
+            std::fs::write(&out, b"existing output").unwrap();
+            cmd.args([
+                "download",
+                "--session",
+                "fixture",
+                "--selector",
+                "a",
+                "--overwrite",
+                "--out",
+            ])
+            .arg(out);
+        } else {
+            cmd.args(["wait-ms", if mode == "ordinary" { "1ms" } else { "60s" }]);
+        }
+        cmd.arg("--json");
+        if mode == "ordinary" {
+            cmd.stdin(std::process::Stdio::null());
+        } else {
+            cmd.env("BSK_CANCEL_ON_STDIN_CLOSE", "1")
+                .stdin(std::process::Stdio::piped());
+        }
+        let mut child = cmd.spawn().unwrap();
+        if mode != "ordinary" {
+            tokio::time::timeout(Duration::from_secs(10), registered.notified())
+                .await
+                .expect("CLI registered business RPC");
+            child
+                .stdin
+                .as_mut()
+                .unwrap()
+                .write_all(b"still connected")
+                .await
+                .unwrap();
+            drop(child.stdin.take());
+        }
+        let start = Instant::now();
+        let output = tokio::time::timeout(Duration::from_secs(8), child.wait_with_output())
+            .await
+            .expect("CLI must settle promptly, including cleanup")
+            .unwrap();
+        server.abort();
+        let _ = server.await;
+        assert_eq!(
+            output.status.code(),
+            Some(if mode == "ordinary" { 0 } else { 2 }),
+            "{mode}: stdout={} stderr={}",
+            String::from_utf8_lossy(&output.stdout),
+            String::from_utf8_lossy(&output.stderr)
+        );
+        if mode != "ordinary" {
+            let body: serde_json::Value = serde_json::from_slice(&output.stdout).unwrap();
+            assert_eq!(body["code"], "cancelled");
+            if mode != "upload-before-dispatch" {
+                assert_eq!(body["message"], "parent cancellation reached daemon");
+            }
+            let received = received.lock().unwrap();
+            let cancel = received.iter().position(|m| *m == Method::Cancel).unwrap();
+            assert!(
+                received[cancel + 1..]
+                    .iter()
+                    .all(|m| *m == Method::TransferRelease),
+                "only cleanup may follow cancellation: {received:?}"
+            );
+        }
+        let ids = ids.lock().unwrap();
+        if mode.contains("stall") {
+            assert_eq!(released.lock().unwrap().len(), 1);
+            assert!(start.elapsed() >= Duration::from_secs(4));
+            // The CLI cannot force an unresponsive daemon to clean up.
+            transfers.release_session("fixture");
+        } else {
+            assert_eq!(
+                *released.lock().unwrap(),
+                *ids,
+                "{mode}: every allocation must be released"
+            );
+            for id in ids.iter() {
+                assert!(!staging_root.join(id).exists(), "staging leaked: {id}");
+            }
+            if mode.starts_with("upload") {
+                let retry = transfers
+                    .begin_upload(TransferBeginParams {
+                        session_id: "fixture".into(),
+                        name: "retry.txt".into(),
+                        byte_size: 300 * 1024 * 1024,
+                    })
+                    .expect("same session must have room for another 300 MiB upload");
+                transfers.release(TransferIdParams {
+                    transfer_id: retry.transfer_id,
+                });
+            }
+        }
+        if mode == "download" {
+            assert_eq!(
+                std::fs::read(home.path().join("out.txt")).unwrap(),
+                b"existing output"
+            );
+            assert!(
+                !std::fs::read_dir(home.path())
+                    .unwrap()
+                    .flatten()
+                    .any(|entry| entry.file_name().to_string_lossy().ends_with(".part"))
+            );
+        }
+    }
+}

evals/browser/cases/regression/oopif-scrollbars/README.md

@@ -0,0 +1,41 @@
+# OOPIF occupied-scrollbar regression
+
+An iframe's content quad includes its child viewport's scrollbar space, while
+`Page.getLayoutMetrics().cssLayoutViewport` excludes that space. Mapping the latter
+onto the whole quad stretches positions and sizes. The full target-local viewport
+must determine scale; the visible viewport must still clip content at every OOPIF
+boundary and constrain target-local action points.
+
+This fixture alternates loopback hostnames across two nested OOPIFs. It includes
+scrolling, borders, padding, scaled iframe owners, a partially clipped button and
+a fully clipped button. Custom scrollbars occupy different widths and heights.
+The `scrollbars` query parameter accepts `both` (default), `vertical`, `horizontal`
+or `none`.
+
+Run the numerical regression with Node 22+ and a local Chrome executable:
+
+```sh
+BSK_GEOMETRY_CHROME=/path/to/chrome pnpm --filter @browser-skill/extension exec vitest run \
+  src/tools/__tests__/snapshot-coordinates.browser.test.ts
+```
+
+The existing browser runner is shared with the snapshot-unit regression. The test:
+
+- Verifies actual OOPIF targets and occupied scrollbar dimensions.
+- Compares snapshot and live geometry with independent DOM rectangles and clipping.
+- Dispatches real root-target clicks and verifies the intended frame/button received them.
+- Rejects fully clipped controls and checks snapshot measurement reuse per target.
+- Covers five device-scale/browser-zoom combinations plus single-axis and no-scrollbar cases.
+
+The runner creates and removes isolated browser profiles. It is opt-in and skipped
+in normal unit runs when `BSK_GEOMETRY_CHROME` is unset.
+
+Run the CLI fixture smoke with a connected test extension:
+
+```sh
+BSK_AUTO_UPDATE=off pnpm eval:browser smoke --case oopif-scrollbars --bsk ./target/debug/bsk
+```
+
+The smoke assertions verify both nested frames have occupied scrollbars, that the
+marker is observed and that the session is closed. Numeric geometry and actual
+click assertions are exercised by the browser test above, not by smoke alone.

evals/browser/cases/regression/oopif-scrollbars/oopif-scrollbars.case.json

@@ -0,0 +1,39 @@
+{
+  "$schema": "../../../schemas/case.schema.json",
+  "schemaVersion": 1,
+  "id": "oopif-scrollbars",
+  "title": "Nested OOPIFs with occupied scrollbars and clipped controls",
+  "suite": "regression",
+  "tags": ["geometry", "iframe", "scroll"],
+  "fixture": { "startPath": "/oopif-scrollbars" },
+  "prompts": {
+    "en": "Open {url}, observe the page and its frames, report the OOPIF-SCROLLBARS marker, then close the session.",
+    "zh-CN": "打开 {url}，观察页面及其 iframe，报告 OOPIF-SCROLLBARS 标记，然后关闭会话。"
+  },
+  "coverage": ["session.start", "session.stop", "page.navigate", "inspect.observe"],
+  "assertions": {
+    "site": [
+      {
+        "label": "nested frame fixture settled",
+        "type": "geometry.ready",
+        "where": { "data.root": true },
+        "minCount": 1
+      },
+      {
+        "label": "both child frames have occupied scrollbars",
+        "type": "geometry.scrollbars",
+        "where": { "data.vertical": true, "data.horizontal": true },
+        "minCount": 2
+      }
+    ],
+    "response": [{ "label": "observed the fixture marker", "includes": "OOPIF-SCROLLBARS" }],
+    "adapter": [{ "label": "browser session was closed", "key": "sessionStopped" }]
+  },
+  "smoke": {
+    "steps": [
+      { "action": "navigate" },
+      { "action": "wait-site-event", "type": "geometry.ready", "where": { "root": true } },
+      { "action": "observe" }
+    ]
+  }
+}

evals/browser/cases/regression/oopif-scrollbars/oopif-scrollbars.fixture.mjs

@@ -0,0 +1,56 @@
+import { page, withRun } from "../../../lib/fixtures.mjs";
+
+export default {
+  id: "oopif-scrollbars",
+  routes: ["/oopif-scrollbars", "/oopif-scrollbars/frame", "/oopif-scrollbars/nested"],
+  render({ pathname, runId, query }) {
+    const root = pathname === "/oopif-scrollbars";
+    const nested = pathname.endsWith("/nested");
+    const mode = query.get("scrollbars") ?? "both";
+    return page({
+      title: "OOPIF scrollbar geometry regression",
+      body: `
+        <style>
+          main { margin: 0; width: auto; }
+          body { width: 2000px; height: 2400px; }
+          html { overflow-anchor: none; }
+          ${!root ? `html { overflow-x: ${mode === "vertical" || mode === "none" ? "hidden" : "scroll"}; overflow-y: ${mode === "horizontal" || mode === "none" ? "hidden" : "scroll"}; } html::-webkit-scrollbar { width: 17px; height: 11px; }` : ""}
+          button { position: absolute; padding: 0; border: 0; border-radius: 0; }
+          #probe { left: ${root ? 180 : nested ? 30 : 100}px; top: ${root ? 360 : nested ? 40 : 160}px; width: 60px; height: 20px; }
+          #edge { position: fixed; right: -20px; bottom: -15px; width: 80px; height: 60px; }
+          #outside { position: fixed; left: calc(100% + 2px); top: calc(100% + 2px); width: 10px; height: 10px; }
+          iframe { position: absolute; box-sizing: content-box; width: 420px; height: 320px;
+            left: 340px; top: 400px; border: 6px solid black; padding: 8px; transform: scale(1.2); transform-origin: 0 0; }
+          #nested { left: 150px; top: 210px; width: 200px; height: 120px; border-width: 4px; padding: 6px; transform: scale(0.8); }
+        </style>
+        <button id="probe" data-geometry-probe>OOPIF-SCROLLBARS</button>
+        ${!root ? '<button id="edge" data-geometry-probe>EDGE</button><button id="outside" data-geometry-probe>OUTSIDE</button>' : ""}
+        ${!nested ? `<iframe id="${root ? "cross" : "nested"}" name="${root ? "cross" : "nested"}" title="${root ? "outer" : "nested"} cross-site frame"></iframe>` : ""}
+      `,
+      script: `
+        history.scrollRestoration = "manual";
+        const child = document.querySelector("iframe");
+        if (child) {
+          const url = new URL(${JSON.stringify(withRun(root ? "/oopif-scrollbars/frame" : "/oopif-scrollbars/nested", runId, { scrollbars: mode }))}, location.href);
+          url.hostname = location.hostname === "127.0.0.1" ? "localhost" : "127.0.0.1";
+          child.src = url.href;
+        }
+        document.addEventListener("click", event => {
+          const probe = event.target.closest("[data-geometry-probe]");
+          if (probe) browserEval.send("geometry.clicked", { probe: probe.id });
+        });
+        window.addEventListener("load", () => {
+          scrollTo(${root ? "80, 240" : nested ? "10, 20" : "40, 100"});
+          requestAnimationFrame(() => requestAnimationFrame(() => {
+            document.documentElement.dataset.geometryReady = "true";
+            if (!${root}) browserEval.send("geometry.scrollbars", {
+              vertical: innerWidth > document.documentElement.clientWidth,
+              horizontal: innerHeight > document.documentElement.clientHeight,
+            });
+            browserEval.send("geometry.ready", { root: ${root} });
+          }));
+        });
+      `,
+    });
+  },
+};

evals/browser/cases/regression/snapshot-coordinates/README.md

@@ -0,0 +1,41 @@
+# DOMSnapshot layout-unit regression (#195)
+
+Source: https://github.com/Tencent/BrowserSkill/pull/195
+
+DOMSnapshot bounds and document scroll offsets retain Blink layout units. Treating them as CSS
+pixels changes both positions and sizes under device scaling/browser zoom, before iframe
+projection or viewport clipping even starts.
+
+The fixture contains a scrolled root, a scrolled same-process iframe, an OOPIF served from the
+other loopback hostname, and a nested iframe in each. Owners have borders, padding and CSS
+transforms. The geometry test compares the production capture's local and top-level rectangles
+against independent DOM border boxes, with at most 2 CSS pixels of layout rounding. It also
+checks that each target reads layout metrics only once. No credentials or personal tabs are used.
+
+Run the geometric assertions with Node 22+ and a local Chrome executable:
+
+```sh
+BSK_GEOMETRY_CHROME=/path/to/chrome pnpm --filter @browser-skill/extension exec vitest run \
+  src/tools/__tests__/snapshot-coordinates.browser.test.ts
+```
+
+The test launches and cleans up its own headless Chrome profiles. It explicitly verifies the
+requested browser zoom and OOPIF topology, so unsupported setups fail rather than silently
+testing a different configuration. It is skipped in ordinary unit runs unless the executable
+is specified. No browser download or new package dependency is required.
+
+The corpus smoke case checks fixture readiness and observable semantics through the real CLI:
+
+```sh
+BSK_AUTO_UPDATE=off pnpm eval:browser smoke --case snapshot-coordinates --bsk ./target/debug/bsk
+```
+
+Smoke alone does **not** certify coordinate accuracy; CLI observations do not expose raw boxes.
+Use the geometric test above for the regression's numeric assertions.
+
+## Related scrollbar regression
+
+The unit-conversion fixture keeps non-occupying OOPIF scrollbars by default. The same
+browser test also runs the dedicated [OOPIF scrollbar fixture](../oopif-scrollbars/README.md),
+which covers occupied scrollbars, two OOPIF boundaries, clipping and real clicks.
+Append `&classic-scrollbars` to this fixture's URL to enable its normal OOPIF scrollbars.

evals/browser/cases/regression/snapshot-coordinates/chrome.mjs

@@ -0,0 +1,99 @@
+import { spawn } from "node:child_process";
+import { once } from "node:events";
+import { mkdir, mkdtemp, rm, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+
+// This regression owns its browser/profile. It never attaches to a user's Chrome.
+export async function withChrome({ executable, deviceScale, zoom }, run) {
+  const profile = await mkdtemp(join(tmpdir(), "bsk-snapshot-coordinates-"));
+  let chrome;
+  let socket;
+  const pending = new Map();
+  try {
+    await mkdir(join(profile, "Default"));
+    await writeFile(
+      join(profile, "Default", "Preferences"),
+      JSON.stringify({
+        partition: { default_zoom_level: { x: Math.log(zoom) / Math.log(1.2) } },
+      }),
+    );
+    chrome = spawn(
+      executable,
+      [
+        "--headless=new",
+        "--no-first-run",
+        "--no-default-browser-check",
+        "--disable-extensions",
+        "--site-per-process",
+        "--remote-debugging-port=0",
+        "--window-size=1600,1200",
+        `--force-device-scale-factor=${deviceScale}`,
+        `--user-data-dir=${profile}`,
+        "about:blank",
+      ],
+      { stdio: ["ignore", "ignore", "pipe"] },
+    );
+    const endpoint = await new Promise((resolve, reject) => {
+      let output = "";
+      const timeout = setTimeout(
+        () => reject(new Error(`Chrome startup timed out: ${output}`)),
+        15_000,
+      );
+      const fail = (error) => {
+        clearTimeout(timeout);
+        reject(error);
+      };
+      chrome.once("error", fail);
+      chrome.once("exit", (code) => fail(new Error(`Chrome exited (${code}): ${output}`)));
+      chrome.stderr.on("data", (chunk) => {
+        output += chunk;
+        const match = output.match(/DevTools listening on (ws:\/\/\S+)/);
+        if (match) {
+          clearTimeout(timeout);
+          resolve(match[1]);
+        }
+      });
+    });
+    socket = new WebSocket(endpoint);
+    await new Promise((resolve, reject) => {
+      socket.addEventListener("open", resolve, { once: true });
+      socket.addEventListener("error", reject, { once: true });
+    });
+    socket.addEventListener("message", ({ data }) => {
+      const reply = JSON.parse(data);
+      const request = pending.get(reply.id);
+      if (!request) return;
+      clearTimeout(request.timeout);
+      pending.delete(reply.id);
+      if (reply.error) request.reject(new Error(JSON.stringify(reply.error)));
+      else request.resolve(reply.result);
+    });
+    let sequence = 0;
+    const send = (method, params = {}, sessionId) =>
+      new Promise((resolve, reject) => {
+        const id = ++sequence;
+        const timeout = setTimeout(() => {
+          pending.delete(id);
+          reject(new Error(`CDP timed out: ${method}`));
+        }, 10_000);
+        pending.set(id, { resolve, reject, timeout });
+        socket.send(JSON.stringify({ id, method, params, sessionId }));
+      });
+    await run(send);
+  } finally {
+    for (const request of pending.values()) {
+      clearTimeout(request.timeout);
+      request.reject(new Error("regression browser closed"));
+    }
+    socket?.close();
+    if (chrome && chrome.exitCode === null && chrome.signalCode === null) {
+      const exited = once(chrome, "exit");
+      const timeout = setTimeout(() => chrome.kill("SIGKILL"), 5_000);
+      chrome.kill();
+      await exited;
+      clearTimeout(timeout);
+    }
+    await rm(profile, { recursive: true, force: true });
+  }
+}

evals/browser/cases/regression/snapshot-coordinates/snapshot-coordinates.case.json

@@ -0,0 +1,33 @@
+{
+  "$schema": "../../../schemas/case.schema.json",
+  "schemaVersion": 1,
+  "id": "snapshot-coordinates",
+  "title": "Scrolled and nested frame coordinate fixture",
+  "suite": "regression",
+  "tags": ["geometry", "iframe", "scroll"],
+  "fixture": { "startPath": "/snapshot-coordinates" },
+  "prompts": {
+    "en": "Open {url}, observe the page and its frames, report the GEOMETRY marker, then close the session.",
+    "zh-CN": "打开 {url}，观察页面及其 iframe，报告 GEOMETRY 标记，然后关闭会话。"
+  },
+  "coverage": ["session.start", "session.stop", "page.navigate", "inspect.observe"],
+  "assertions": {
+    "site": [
+      {
+        "label": "root fixture scrolled and settled",
+        "type": "geometry.ready",
+        "where": { "data.root": true },
+        "minCount": 1
+      }
+    ],
+    "response": [{ "label": "observed the fixture marker", "includes": "GEOMETRY-195" }],
+    "adapter": [{ "label": "browser session was closed", "key": "sessionStopped" }]
+  },
+  "smoke": {
+    "steps": [
+      { "action": "navigate" },
+      { "action": "wait-site-event", "type": "geometry.ready", "where": { "root": true } },
+      { "action": "observe" }
+    ]
+  }
+}

evals/browser/cases/regression/snapshot-coordinates/snapshot-coordinates.fixture.mjs

@@ -0,0 +1,52 @@
+import { page, withRun } from "../../../lib/fixtures.mjs";
+
+export default {
+  id: "snapshot-coordinates",
+  routes: ["/snapshot-coordinates", "/snapshot-coordinates/frame", "/snapshot-coordinates/nested"],
+  render({ pathname, runId, query }) {
+    const root = pathname === "/snapshot-coordinates";
+    const nested = pathname.endsWith("/nested");
+    return page({
+      title: "Snapshot coordinate regression",
+      body: `
+        <style>
+          main { margin: 0; width: auto; }
+          body { width: 2000px; height: 2400px; }
+          html { overflow-anchor: none; }
+          ${query.get("scrollbars") === "none" ? "html { scrollbar-width: none; }" : ""}
+          button { position: absolute; box-sizing: border-box; padding: 0; border: 2px solid black; border-radius: 0; }
+          #probe { left: ${root ? 180 : 100}px; top: ${root ? 360 : 160}px; width: 120px; height: 40px; }
+          iframe { position: absolute; box-sizing: content-box; width: 320px; height: 220px;
+            border: 6px solid black; padding: 8px; transform: scale(1.25); transform-origin: 0 0; }
+          #same { left: 340px; top: 400px; }
+          #cross { left: 820px; top: 400px; }
+          #nested { left: 150px; top: 210px; width: 130px; height: 70px; border-width: 2px; padding: 4px; transform: scale(0.8); }
+          ${nested ? "#probe { left: 30px; top: 40px; width: 60px; height: 20px; }" : ""}
+        </style>
+        <button id="probe" data-geometry-probe>GEOMETRY-195</button>
+        ${root ? `<iframe id="same" name="same" title="same-process frame" src="${withRun("/snapshot-coordinates/frame", runId)}"></iframe><iframe id="cross" name="cross" title="cross-site frame"></iframe>` : ""}
+        ${!root && !nested ? `<iframe id="nested" name="nested" title="nested frame" src="${withRun("/snapshot-coordinates/nested", runId)}"></iframe>` : ""}
+      `,
+      script: `
+        history.scrollRestoration = "manual";
+        const cross = document.querySelector("#cross");
+        if (cross) {
+          const url = new URL(${JSON.stringify(withRun("/snapshot-coordinates/frame", runId))}, location.href);
+          url.hostname = location.hostname === "127.0.0.1" ? "localhost" : "127.0.0.1";
+          // Isolate unit conversion from the pre-existing OOPIF scrollbar-width
+          // projection issue. ?classic-scrollbars retains that separate reproduction.
+          if (!new URLSearchParams(location.search).has("classic-scrollbars")) url.searchParams.set("scrollbars", "none");
+          cross.src = url.href;
+        }
+        window.addEventListener("load", () => {
+          scrollTo(${root ? "80, 240" : nested ? "10, 20" : "40, 100"});
+          requestAnimationFrame(() => requestAnimationFrame(() => {
+            window.geometryReady = true;
+            document.documentElement.dataset.geometryReady = "true";
+            browserEval.send("geometry.ready", { root: ${root} });
+          }));
+        });
+      `,
+    });
+  },
+};

evals/browser/tests/eval.test.mjs

@@ -41,17 +41,23 @@ test("case manifests are discovered, ordered, and grouped into suites", () => {
       "diagnostics",
       "mobile-emulation",
       "generated-form",
+      "oopif-scrollbars",
+      "snapshot-coordinates",
     ],
   );
-  assert.deepEqual(repositorySummary(cases, fixtureRegistry).suites, { core: 6, matrix: 1 });
+  assert.deepEqual(repositorySummary(cases, fixtureRegistry).suites, {
+    core: 6,
+    matrix: 1,
+    regression: 2,
+  });
 });
 
 test("repository validation links every case to a fixture and valid workflow evidence", () => {
   assert.deepEqual(validateRepositoryCases(cases, fixtureRegistry), []);
   const summary = repositorySummary(cases, fixtureRegistry);
-  assert.equal(summary.cases, 7);
-  assert.equal(summary.fixtureModules, 8);
-  assert.equal(summary.fixtureRoutes, 12);
+  assert.equal(summary.cases, 9);
+  assert.equal(summary.fixtureModules, 10);
+  assert.equal(summary.fixtureRoutes, 18);
 });
 
 test("manifest validation rejects unknown operations and incomplete workflow steps", () => {

install.ps1

@@ -21,6 +21,7 @@ $ErrorActionPreference = "Stop"
 
 $Repo = if ($env:BSK_REPO) { $env:BSK_REPO } else { "Tencent/BrowserSkill" }
 $InstallDir = if ($env:BSK_INSTALL_DIR) { $env:BSK_INSTALL_DIR } else { Join-Path $HOME ".local\bin" }
+$InstallDir = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath($InstallDir)
 $GitHub = "https://github.com/${Repo}"
 
 function Write-Log {
@@ -37,11 +38,17 @@ function Write-Die {
 # ── Platform / architecture detection ─────────────────────────────────────────
 
 function Get-PlatformTriple {
-    $arch = [System.Runtime.InteropServices.RuntimeInformation]::ProcessArchitecture
+    # RuntimeInformation.ProcessArchitecture can be unavailable in Windows PowerShell 5.1.
+    # WOW64 exposes the native architecture separately from the 32-bit process.
+    $arch = $env:PROCESSOR_ARCHITEW6432
+    if (-not $arch) { $arch = $env:PROCESSOR_ARCHITECTURE }
+    if (-not $arch) {
+        Write-Die "could not detect Windows architecture: PROCESSOR_ARCHITEW6432 and PROCESSOR_ARCHITECTURE are empty"
+    }
 
     switch ($arch) {
-        "X64"  { $archId = "x64" }
-        "Arm64" { $archId = "arm64" }
+        "AMD64" { $archId = "x64" }
+        "ARM64" { $archId = "arm64" }
         default { Write-Die "unsupported architecture: $arch (x64 and ARM64 only)" }
     }
 
@@ -64,56 +71,86 @@ function Get-PlatformTriple {
 function Add-ToUserPath {
     param([string]$Dir)
 
-    $currentUserPath = [Environment]::GetEnvironmentVariable("PATH", "User") -split ";" | Where-Object { $_ }
+    $currentUserPath = @([Environment]::GetEnvironmentVariable("PATH", "User") -split ";" | Where-Object { $_ })
 
-    if ($currentUserPath -contains $Dir) {
-        Write-Log "$Dir is already in your user PATH"
+    $newUserPath = (@($Dir) + @($currentUserPath | Where-Object { $_ -ine $Dir })) -join ";"
+    if (($currentUserPath -join ";") -ceq $newUserPath) {
+        Write-Log "$Dir is already first in your user PATH"
         return
     }
 
-    $newUserPath = ($currentUserPath + $Dir) -join ";"
     [Environment]::SetEnvironmentVariable("PATH", $newUserPath, "User")
-    Write-Log "added ${Dir} to user PATH"
+    Write-Log "placed ${Dir} first in user PATH"
 }
 
 function Add-ToSessionPath {
     param([string]$Dir)
 
-    $pathEntries = $env:PATH -split ";" | Where-Object { $_ }
-    if ($pathEntries -contains $Dir) {
-        return
-    }
-
-    $env:PATH = "$Dir;$env:PATH"
+    $pathEntries = @($env:PATH -split ";" | Where-Object { $_ -and $_ -ine $Dir })
+    $env:PATH = (@($Dir) + $pathEntries) -join ";"
 }
 
 # ── Git Bash (bash environment) PATH helper ──────────────────────────────────
 
 function Add-ToBashProfile {
-    param([string]$Dir)
+    param([string]$Dir, [string]$BashRc = (Join-Path $HOME ".bashrc"))
 
     # Convert Windows path (e.g. C:\Users\foo\.local\bin) to Git-Bash Unix-style (/c/Users/foo/.local/bin)
     $unixPath = $Dir -replace '\\', '/'
     if ($unixPath -match '^([A-Z]):(.*)$') {
         $unixPath = '/' + $matches[1].ToLower() + $matches[2]
     }
-    $bashRc = Join-Path $HOME ".bashrc"
-    $exportLine = "export PATH=""${unixPath}:`$PATH""  # bsk CLI"
+    # Single-quote the literal directory; only the existing PATH is expanded.
+    $shellQuote = "'" + [char]34 + "'" + [char]34 + "'"
+    $quotedPath = "'" + $unixPath.Replace("'", $shellQuote) + "'"
+    $exportLine = "export PATH=${quotedPath}:`"`$PATH`"  # bsk CLI"
 
-    if (Test-Path $bashRc) {
-        $content = Get-Content $bashRc -Raw -ErrorAction SilentlyContinue
-        if ($content -match [regex]::Escape($unixPath)) {
+    if (Test-Path -LiteralPath $BashRc) {
+        $content = [System.IO.File]::ReadAllText($BashRc)
+        if ($content.Contains($exportLine)) {
             Write-Log "$unixPath is already in ~/.bashrc"
             return
         }
     }
 
-    Add-Content $bashRc "`n$exportLine" -Encoding ASCII
+    # Explicit BOM-less UTF-8 also works in Windows PowerShell 5.1.
+    [System.IO.File]::AppendAllText($BashRc, "`n$exportLine`n", (New-Object System.Text.UTF8Encoding($false)))
     Write-Log "added ${unixPath} to ~/.bashrc"
 }
 
 # ── Main ──────────────────────────────────────────────────────────────────────
 
+# Stage on the destination volume before stopping the daemon. Never truncate
+# the installed executable: failed replacement must leave it usable.
+function Install-Binary {
+    param([string]$Source, [string]$Target)
+
+    $staged = "$Target.install-$([Guid]::NewGuid().ToString('N'))"
+    try {
+        [System.IO.File]::Copy($Source, $staged)
+        # The running daemon may come from another installation directory.
+        # Use the downloaded CLI: older versions have broken Windows liveness checks.
+        # Stop verifies daemon identity and uses the current BSK_HOME.
+        # Fail closed for both new installs and replacements; never discard daemon metadata here.
+        & $Source daemon stop
+        if ($LASTEXITCODE -ne 0) {
+            $daemonHome = if ($env:BSK_HOME) { $env:BSK_HOME } else { Join-Path $HOME ".bsk" }
+            $daemonInfoPath = $ExecutionContext.SessionState.Path.GetUnresolvedProviderPathFromPSPath((Join-Path $daemonHome "daemon.json"))
+            throw "could not stop bsk daemon; installation was not changed. Stop any running bsk daemon, remove '$daemonInfoPath', then retry the installer."
+        }
+        if ([System.IO.File]::Exists($Target)) {
+            # PowerShell 5.1 converts $null to an empty path for string parameters.
+            [System.IO.File]::Replace($staged, $Target, [NullString]::Value)
+        }
+        else {
+            [System.IO.File]::Move($staged, $Target)
+        }
+    }
+    finally {
+        if ([System.IO.File]::Exists($staged)) { [System.IO.File]::Delete($staged) }
+    }
+}
+
 function Main {
     $platform = Get-PlatformTriple
 
@@ -136,14 +173,20 @@ function Main {
         Write-Log "latest version is ${version}"
     }
 
+    $platformKey = $platform.PlatformKey
+    $asset = $null
+    if ($manifest -and $manifest.assets) {
+        $asset = $manifest.assets.$platformKey
+    }
+    # ARM64 is not in the current release matrix. Require a published entry
+    # before attempting it, while preserving legacy x64 installs without a manifest.
+    if ($platform.ArchId -eq "arm64" -and -not $asset) {
+        Write-Die "version.json does not list a Windows ARM64 package for bsk $version"
+    }
+
     $archiveName = "bsk-v${version}-$($platform.TargetTriple).zip"
     $downloadUrl = "${GitHub}/releases/download/${tag}/${archiveName}"
-
-    $expectedSha = $null
-    $platformKey = $platform.PlatformKey
-    if ($manifest -and $manifest.assets) {
-        $expectedSha = $manifest.assets.$platformKey.sha256
-    }
+    $expectedSha = if ($asset) { $asset.sha256 } else { $null }
     if (-not $expectedSha) {
         if (-not $manifest) {
             Write-Log "warning: could not fetch version.json; skipping checksum verification"
@@ -154,17 +197,21 @@ function Main {
     }
 
     $tempDir = Join-Path ([System.IO.Path]::GetTempPath()) ([System.IO.Path]::GetRandomFileName())
-    New-Item -ItemType Directory -Path $tempDir -Force | Out-Null
+    [System.IO.Directory]::CreateDirectory($tempDir) | Out-Null
 
     try {
         $archivePath = Join-Path $tempDir $archiveName
 
         Write-Log "downloading ${downloadUrl}"
-        Invoke-WebRequest -Uri $downloadUrl -OutFile $archivePath -UseBasicParsing -ErrorAction Stop
+        # PowerShell 5.1's -OutFile treats brackets as wildcards. Write raw HTTP bytes literally.
+        $response = Invoke-WebRequest -Uri $downloadUrl -UseBasicParsing -ErrorAction Stop
+        try {
+            [System.IO.File]::WriteAllBytes($archivePath, $response.RawContentStream.ToArray())
+        } finally { $response.RawContentStream.Dispose() }
 
         if ($expectedSha) {
             Write-Log "verifying checksum"
-            $actualSha = (Get-FileHash -Algorithm SHA256 -Path $archivePath).Hash
+            $actualSha = (Get-FileHash -Algorithm SHA256 -LiteralPath $archivePath).Hash
             if ($actualSha -ieq $expectedSha) {
                 Write-Log "checksum OK"
             }
@@ -174,17 +221,17 @@ function Main {
         }
 
         Write-Log "extracting ${archiveName}"
-        Expand-Archive -Path $archivePath -DestinationPath $tempDir -Force
+        # PowerShell 5.1's Expand-Archive treats the destination as a wildcard path.
+        Add-Type -AssemblyName System.IO.Compression.FileSystem
+        [System.IO.Compression.ZipFile]::ExtractToDirectory($archivePath, $tempDir)
 
-        if (-not (Test-Path (Join-Path $tempDir "bsk.exe"))) {
+        if (-not (Test-Path -LiteralPath (Join-Path $tempDir "bsk.exe"))) {
             Write-Die "bsk.exe not found in archive"
         }
 
-        if (-not (Test-Path $InstallDir)) {
-            New-Item -ItemType Directory -Path $InstallDir -Force | Out-Null
-        }
+        [System.IO.Directory]::CreateDirectory($InstallDir) | Out-Null
 
-        Copy-Item -Path (Join-Path $tempDir "bsk.exe") -Destination (Join-Path $InstallDir "bsk.exe") -Force
+        Install-Binary -Source (Join-Path $tempDir "bsk.exe") -Target (Join-Path $InstallDir "bsk.exe")
 
         Write-Log "installed bsk to $InstallDir\bsk.exe"
 
@@ -199,19 +246,21 @@ function Main {
 
         # Verify
         $bskPath = Join-Path $InstallDir "bsk.exe"
-        if (Get-Command bsk -ErrorAction SilentlyContinue) {
-            & bsk --version
-        }
-        else {
-            Write-Log "verify install: & ""$bskPath"" --version"
+        & $bskPath --version
+        if ($LASTEXITCODE -ne 0) { throw "installed bsk failed verification" }
+
+        $command = Get-Command bsk -ErrorAction SilentlyContinue
+        if (-not $command -or $command.CommandType -ne "Application" -or $command.Source -ine $bskPath) {
+            Write-Log "warning: 'bsk' does not resolve to $bskPath in this session; check Get-Command bsk -All for a conflicting command"
         }
 
         Write-Log "done"
         Write-Host ""
-        Write-Host "Open a new terminal (PowerShell / Git Bash) for PATH changes to take full effect."
+        Write-Host "This PATH check covers the current session only; a new terminal may prefer a Machine PATH entry or alias."
+        Write-Host "In a new PowerShell terminal, run Get-Command bsk -All and confirm the first result is $bskPath."
     }
     finally {
-        Remove-Item -Recurse -Force $tempDir -ErrorAction SilentlyContinue
+        Remove-Item -LiteralPath $tempDir -Recurse -Force -ErrorAction SilentlyContinue
     }
 }
 

packages/dsh-plugin-browserskill/README.md

@@ -1,13 +1,51 @@
-# dsh-plugin-browserskill
+# BrowserSkill for DeepSeek Harness
 
-npm: [`@wxg-prc-cpg/browser-skill-dsh-plugin`](https://www.npmjs.com/package/@wxg-prc-cpg/browser-skill-dsh-plugin)
+[![npm version](https://img.shields.io/npm/v/@wxg-prc-cpg/browser-skill-dsh-plugin)](https://www.npmjs.com/package/@wxg-prc-cpg/browser-skill-dsh-plugin)
 
-A [DeepSeek Harness](https://github.com/deepseek-ai/deepseek-harness) (dsh) tool plugin that exposes
-[BrowserSkill](https://github.com/Tencent/BrowserSkill) (`bsk`) browser automation to the model.
+Use [BrowserSkill](https://github.com/Tencent/BrowserSkill) in
+[DeepSeek Harness](https://github.com/deepseek-ai/deepseek-harness) (`dsh`) to browse
+websites, fill forms, and capture screenshots through native `browser_*` tools.
+Browser tasks run in Agent Windows, with a live view in the dsh Web UI.
 
-Each action maps to one `bsk <cmd> --json` invocation: the plugin spawns the bsk CLI, parses its
-structured JSON output, and returns a canonical typed value. The bsk daemon, browser, and browser
-extension keep owning the actual browser control — this package is a thin, well-typed bridge.
+## Installation
+
+Before installing the plugin:
+
+- Install [DeepSeek Harness](https://github.com/deepseek-ai/deepseek-harness) and
+  [pnpm](https://pnpm.io/installation), which dsh uses to manage plugins.
+- Install the `bsk` CLI and connect the BrowserSkill extension in Chrome or Edge.
+  Follow the [BrowserSkill setup guide](https://github.com/Tencent/BrowserSkill#quick-start).
+- Make sure `bsk` is on the `PATH` used to start dsh, or set `bskPath` in the plugin configuration.
+
+Install the plugin into the `web` profile, then start it:
+
+```sh
+dsh plugin --profile web add @wxg-prc-cpg/browser-skill-dsh-plugin
+dsh --profile web
+```
+
+Replace `web` with your profile name if you use a different profile. The plugin
+includes the `browser-skill` skill; no separate `bsk install-skill` step is needed.
+
+In a conversation, try:
+
+```text
+/browser-skill open example.com and summarize the page.
+```
+
+By default, the browser tools become available when the skill is invoked.
+
+## Updating
+
+Installed plugins do not update automatically. To upgrade this plugin to npm's
+`latest` version, including versions outside the profile's saved dependency range:
+
+```sh
+dsh plugin --profile web update @wxg-prc-cpg/browser-skill-dsh-plugin --latest
+```
+
+Restart that dsh profile after upgrading. This command updates the plugin; update
+the `bsk` CLI and browser extension separately when a release requires it.
 
 ## Tools
 
@@ -20,23 +58,7 @@ extension keep owning the actual browser control — this package is a thin, wel
 | `browser_tabs` | `list`, `create`, `select`, `close`, `borrow`, `return` | Manage Agent Window tabs and temporarily borrow user tabs. |
 | `browser_assist` | `resize`, `emulate`, `request-help` | Resize or emulate the browser and pause for human-only steps. |
 
-`bsk evaluate` and `bsk record` are intentionally not exposed by this plugin: arbitrary page
-evaluation is a higher-risk capability, while recording is long-running and needs a dedicated
-DeepSeek Harness lifecycle before it can be added safely.
-
-## Agent skill (progressive disclosure)
-
-Beyond the tools, the plugin publishes the **`browser-skill` agent skill** through the harness's
-official skill seam (`ctx.skills.register`): the catalog entry (name + routing description) is
-resident in `<available_skills>`, and the body is loaded only when the model invokes the `skill`
-tool. Its single source is the DSH-specific `skill/SKILL.md`, which documents only structured
-`browser_*` calls and their plugin semantics. The repository-root CLI skill is intentionally not
-concatenated: its command examples belong to a different execution interface and would bypass
-the plugin's ownership, live observation UI, cancellation, and cleanup path if followed directly.
-The build rejects internal CLI-name leakage, command-line code blocks, unknown browser tools, and
-missing supported browser tools before embedding the Markdown. Registration and every pre-step
-catalog snapshot are pure in-memory reads (no disk/process/daemon); compositions without the skill
-seam degrade silently.
+Arbitrary page-script evaluation and interaction recording are not supported.
 
 ## Multi-session model
 
@@ -55,136 +77,73 @@ an explicit `session` argument naming a foreign or unknown id is rejected, the `
 `browser_session` shows plugin-created sessions only (no daemon-wide view), and stop/unload cleanup
 can never touch a session owned by another program.
 
-## Installation
-
-The plugin follows the standard dsh bundle layout (`dsh.bundle` manifest + `cordis.patch.yml`):
-
-```sh
-dsh plugin --profile <name> add @wxg-prc-cpg/browser-skill-dsh-plugin
-dsh --profile <name>
-```
-
-Prerequisite: the `bsk` CLI must be installed and on `PATH`, and the BrowserSkill browser extension
-(Chrome or Edge) must be connected — see the
-[BrowserSkill README](https://github.com/Tencent/BrowserSkill). When bsk is missing, tool calls fail
-with install guidance instead of a bare spawn error.
-
 ## Configuration
 
-All fields are optional and validated through the plugin's Schemastery `Config`:
+After installing the plugin, edit your profile's `cordis.patch.yml`. For the `web`
+profile, the default location is `~/.dsh/profiles/web/cordis.patch.yml`. If you set
+`DSH_HOME`, use `$DSH_HOME/profiles/web/cordis.patch.yml` instead. Replace `web` with
+your profile name as needed.
+
+If the file contains only comments and `[]`, keep the comments and replace `[]`
+with the YAML below. If it already contains patch entries, add this entry to the
+existing list or edit its existing `id: browserskill` entry. Keep a single
+top-level YAML list. This overrides the plugin registered by the installed bundle:
 
 ```yaml
-# cordis.patch.yml override example
-- insert:
-    - id: browserskill
-      name: "@wxg-prc-cpg/browser-skill-dsh-plugin"
-      config:
-        bskPath: bsk          # path to the bsk binary (default: resolve from PATH)
-        defaultTimeoutMs: 120000
-        maxSessions: 5
-        # observationEnabled: true     # live PiP/overlay observation (below)
-        # thumbnailIntervalMs: 1500    # frame cadence while a session is active
-        # idleIntervalMs: 8000         # idle cadence / recent-activity window
-        # lazyTools: true              # reveal browser_* tools only after the skill is invoked
+- id: browserskill
+  config:
+    bskPath: bsk
+    defaultTimeoutMs: 120000
+    maxSessions: 5
+    observationEnabled: true
+    thumbnailIntervalMs: 1500
+    idleIntervalMs: 8000
+    lazyTools: true
 ```
 
-- **`lazyTools` (default `true`)** — the final progressive-disclosure stage: the six
-  `browser_*` tool schemas stay OUT of the system prompt (zero schema tokens) until the
-  `browser-skill` skill is actually invoked — the skill catalog entry is the only
-  advertisement. One successful invocation (model tool call, or a `/browser-skill` user
-  gesture) registers the whole suite for the rest of the process; repeated invocations are
-  no-ops, and sessions resumed with a past invocation in their durable log reveal the suite
-  on entry. Set `false` for the legacy always-on registration.
+Change `bskPath` to the full path of your CLI binary if it is not on dsh's `PATH`.
+A patch replaces the entry's entire `config` object, so keep all overrides you need
+together in that object.
 
-## Observation overlay (PiP mini-window)
+Configuration changes follow `dsh.profile.patchReload` in the profile's
+`package.json`: `live` (the default for `web`) applies changes when you save the
+patch file; `startup` requires restarting the profile. Restart after upgrading
+the plugin in either case.
 
-When the plugin runs inside the dsh Web UI, an **observation overlay** floats over the app
-(registered into the `shell.overlay` seat): a breathing thumbnail per owned session plus its
-current action and elapsed time. The card docks at the top-right of the content area (clear of
-the composer and the shell's header controls) and wears the **BrowserSkill product family's own
-look**: the overlay reuses `@browser-skill/ui` components (`Button`, `cn`) and its oklch design
-tokens (`--card`, `--primary`, `--destructive`, `--ring`, …), status dots spec'd after the
-extension popup's connection indicator, and Remix icons. The BSK utility sheet is compiled
-scoped under the `.bsk-obs` root class (`scripts/build-client-css.mjs`), so the overlay looks
-like the BrowserSkill extension without leaking a single selector into the host shell — and the
-shell's theme cannot bleed back in.
+All fields are optional; omitted fields use the defaults below:
 
-- **Lifecycle**: hidden while the plugin owns no sessions; appears on the first
-  `browser_session` start action; disappears when all sessions stop (or the plugin unloads).
-- **Focus view**: status row (green/idle/red dot + session + action + mm:ss), the latest page
-  frame (while viewed, refreshes every ~1.5s while active, ~8s when idle; the last good frame stays on
-  stage while the next one loads, and is kept on errors so the card does not flash),
-  and a compact icon toolbar (Interrupt + Pop out, hover for the label).
-- **Interrupt**: one click kills the in-flight bsk command of the focus session (same semantics
-  as the chat Stop button — the current action fails, the agent run may continue). Strip items
-  carry their own hover interrupt button.
-- **Multi-session strip**: every session gets a tile (mini frame + id + status dot); focus
-  auto-follows the most recently active session; clicking a tile pins focus (pin badge, click
-  again to release); errored sessions get a red edge without stealing focus; sessions the daemon
-  lost are greyed out; prolonged daemon/browser outage shows "browser unavailable" and greys
-  the interrupt button until captures recover.
-- **Drag & resize**: drag the header to move the card; drag any of the four
-  corners to resize (min 240×180, max 80% of the viewport; no visible grip).
-  Both are remembered for the page lifetime.
-- **Pop out (PiP)**: upgrades the card into a native Document PiP window (requires a user
-  gesture, per browser rules), sized from the current card; closing the PiP falls back to the
-  in-page card with state intact. Browsers without Document PiP simply hide the button.
-- **Screenshot demand**: the client requests periodic screenshots while an observation view is
-  visible, using the PiP document's visibility when popped out. Hidden or collapsed views can
-  keep subscribing to state without requesting screenshots. The first screenshot subscriber
-  starts capture scheduling; the last one's departure cancels timers and skips queued captures.
-  An already running capture may finish. Demand applies to the service's owned sessions, not just
-  the selected session.
-- **Wire**: `GET /bsk-observation/events` is the live synchronization channel (SSE). Every connection,
-  including reconnects, starts with `{ type: "snapshot", sessions, available }`, followed by
-  `upsert`, `remove`, `reset`, and `availability` events on the same stream. Replace local state
-  with each snapshot before applying subsequent events. Use `?thumbnails=0` for state-only
-  subscriptions or `?thumbnails=1` to request screenshots; omitting the parameter defaults to
-  requesting screenshots for compatibility. Closing the stream releases its screenshot demand.
-  `GET /bsk-observation/state` remains a one-time `{ sessions, available }` read and does not
-  request screenshots. It has no ordering guarantee relative to a separate SSE connection;
-  live clients should initialize and resynchronize from the stream's snapshot instead.
-  The host also serves `POST /bsk-observation/interrupt`, `POST /bsk-observation/stop`, and
-  `GET /bsk-observation/thumbnail/<attachmentId>` through the dsh `webServer` route seam
-  (dsh 0.1's Typert Remote pipeline is closed to out-of-tree packages). All commands for one
-  session — tool calls and frame captures alike — run through a per-session FIFO, because the
-  daemon accepts only one unfinished command per session.
-- **Programmatic subscription**: `ObservationService.subscribe(listener, { thumbnails: false })`
-  subscribes to state without requesting screenshots. On an active service, the listener receives
-  the initial `snapshot` synchronously, before `subscribe` returns, then receives subsequent
-  changes. `thumbnails` defaults to `true`, so callers should choose it explicitly. The returned
-  unsubscribe function is safe to call repeatedly and releases this subscription's screenshot
-  demand. Subscribing after service disposal is a no-op.
-- **Trust model**: these routes expose live screenshots (and an interrupt write), so they
-  replicate the browser-trust fence dsh applies to its own `/api` routes: the request Host
-  must be a loopback authority (`localhost`, `127.0.0.0/8`, `[::1]`), a present Origin must
-  match the Host, `sec-fetch-site: cross-site` is refused, and POST requires an
-  `application/json` body (cross-site simple requests can never satisfy that). The channel is
-  therefore built for **loopback-only serving** — binding the dsh web server to `0.0.0.0` and
-  reaching it through a LAN address will (deliberately) fail the fence; do not put these
-  routes behind a non-loopback reverse proxy without adding your own authentication.
-- Configure with `observationEnabled` / `thumbnailIntervalMs` / `idleIntervalMs`.
+| Option | Default | Purpose |
+| --- | --- | --- |
+| `bskPath` | `bsk` | Path to the CLI binary. |
+| `defaultTimeoutMs` | `120000` | Default command timeout in milliseconds. |
+| `maxSessions` | `5` | Maximum concurrent sessions started by this plugin. |
+| `observationEnabled` | `true` | Enable live browser observation. |
+| `thumbnailIntervalMs` | `1500` | Screenshot interval for active sessions, in milliseconds. |
+| `idleIntervalMs` | `8000` | Screenshot interval for idle sessions and the recent-activity window, in milliseconds. |
+| `lazyTools` | `true` | Reveal the browser tools when the skill is invoked. Set `false` to register them at startup. |
 
-## Behavior notes
+With `lazyTools: true`, only the skill's catalog entry is initially advertised to
+the model. The six `browser_*` tool schemas are added to the system prompt after
+the `browser-skill` skill is successfully invoked, either by the model or through
+`/browser-skill`. Set `lazyTools: false` to make the tools available immediately.
 
-- **Cancellation**: aborting a tool call (`exec.signal`) kills the underlying bsk child process,
-  matching BrowserSkill's cooperative tool-cancellation model.
-- **UI cards**: calls render as terminal cards (command line as title, output as the completed
-  card). Screenshots additionally attach the image itself when the host mounts an attachment store
-  and the active model route declares image input; otherwise the PNG path is returned.
-- **Web UI toolview (browser half)**: the package is dual-face. `dsh.client` (platform `web`) ships
-  `lib/client.cjs`, which registers a keyed `tool.call.toolview` view for `browser_inspect`. The
-  custom view keeps a terminal block for every inspect action and, when a screenshot result carries
-  an image block, resolves the durable attachment through the client session's authorized
-  `readAttachment` RPC and renders it with the shared `MessageImage` thumbnail/lightbox atoms.
-  The other five tools keep the stock terminal card. The bundle follows the dsh client
-  contract: a CJS closure factory handed to `window.__ModuleLoader__.load`, platform modules
-  (`react`, `dsh-client-ui-*`) external, everything else inlined, CSS Modules compiled by
-  lightningcss.
-- **Errors**: non-zero bsk exits surface the CLI's JSON error envelope (`code`, `message`, `hint`)
-  so the model gets the daemon's actionable guidance.
-- **Long-running work** (e.g. `bsk record`) is not backgrounded via `ctx.jobs` yet — tracked as a
-  follow-up.
+## Live browser view
+
+The dsh Web UI shows the plugin's browser sessions in a floating panel. If your
+profile provides the `dsh-better-sidebar` integration, the view appears in a
+**Browser Skill** sidebar tab instead.
+
+- See the current action, elapsed time, and recent screenshot for each session.
+- Select a session to focus on it. The sidebar view follows the current conversation.
+- Use **Interrupt** to cancel the current browser command. The agent may continue
+  with another action afterward.
+- Drag or resize the floating panel, or use **Pop out** to open a Picture-in-Picture
+  window in browsers that support it.
+- Periodic screenshots are requested while a browser observation view is visible.
+  Configure the active and idle intervals with the options above.
+
+The observation endpoints require a loopback address such as `localhost` or
+`127.0.0.1`. Access through a LAN hostname or non-loopback reverse proxy is not supported.
 
 ## Development
 
@@ -195,22 +154,47 @@ pnpm --filter @wxg-prc-cpg/browser-skill-dsh-plugin test     # unit tests mock b
 pnpm --filter @wxg-prc-cpg/browser-skill-dsh-plugin build    # tsdown -> lib/
 ```
 
+See the [development notes](https://github.com/Tencent/BrowserSkill/blob/main/packages/dsh-plugin-browserskill/docs/development.md)
+for skill registration, tool results, and observation APIs in the current source.
+
 ## Publishing
 
-The GitHub Actions workflow **Release dsh plugin** publishes this package to npm
-as `@wxg-prc-cpg/browser-skill-dsh-plugin`. The Cordis plugin id, client
-bundle registration, and `cordis.patch.yml` name are the same specifier so
-dsh can import and materialize the plugin without a ModuleLoader id mismatch.
+The [Release dsh plugin workflow](https://github.com/Tencent/BrowserSkill/blob/main/.github/workflows/release-dsh-plugin.yml)
+publishes the package and this README to npm. Pushing a `dsh-plugin-vX.Y.Z` tag
+triggers it; ordinary commits to `main` do not.
 
-Trigger it by pushing a tag that matches `package.json`'s `version`:
+1. Commit this README and any other changes intended for the release.
+2. From the repository root, run the
+   [release script](https://github.com/Tencent/BrowserSkill/blob/main/scripts/release.mjs)
+   with a new stable version, replacing `<version>` below. The script updates the
+   CLI, extension, and DSH plugin versions, commits the version changes, and creates
+   their release tags:
 
-```sh
-git tag dsh-plugin-v0.1.2
-git push origin dsh-plugin-v0.1.2
-```
+   ```sh
+   node scripts/release.mjs <version>
+   ```
 
-Or run the workflow from the Actions tab (`workflow_dispatch`). The job reads the
-`NPM_TOKEN` secret from the `npm-publish` GitHub Environment.
+3. Push the version commit to the release branch, then push the DSH plugin tag
+   created by the script, using the same `<version>`:
+
+   ```sh
+   git push origin HEAD
+   git push origin dsh-plugin-v<version>
+   ```
+
+   This publishes the DSH plugin. Push the CLI and extension tags separately when
+   those components are ready for release.
+
+The workflow checks the version, runs typechecks and tests, builds the package,
+and publishes it to npm.
+
+You can also run the workflow manually from GitHub Actions on the intended release
+ref. Both triggers require an unpublished version and the `NPM_TOKEN` secret in the
+`npm-publish` GitHub Environment.
+
+npm updates the package README only when a new version is published, including
+for documentation-only changes. Published versions cannot be overwritten. See
+[npm's README update rules](https://docs.npmjs.com/about-package-readme-files/).
 
 ## License
 

packages/dsh-plugin-browserskill/docs/development.md

@@ -0,0 +1,90 @@
+# DSH plugin development notes
+
+For installation, usage, and configuration, see the [plugin README](../README.md).
+These notes describe the current source on this branch; a published npm version may
+not include later changes.
+
+## Tool execution
+
+The plugin runs the `bsk` CLI and parses its JSON output. The daemon and browser
+extension perform the browser operations. The published package name is also the
+Cordis plugin id, client bundle registration id, and `cordis.patch.yml` plugin name.
+Keep these identifiers aligned so dsh can load both halves of the plugin.
+
+## Agent skill
+
+Beyond the tools, the plugin publishes the **`browser-skill` agent skill** through the harness's
+official skill seam (`ctx.skills.register`): the catalog entry (name + routing description) is
+resident in `<available_skills>`, and the body is loaded only when the model invokes the `skill`
+tool. Its single source is the DSH-specific `skill/SKILL.md`, which documents only structured
+`browser_*` calls and their plugin semantics. The repository-root CLI skill is intentionally not
+concatenated: its command examples belong to a different execution interface and would bypass
+the plugin's ownership, live observation UI, cancellation, and cleanup path if followed directly.
+The build rejects internal CLI-name leakage, command-line code blocks, unknown browser tools, and
+missing supported browser tools before embedding the Markdown. Registration and every pre-step
+catalog snapshot are pure in-memory reads (no disk/process/daemon); compositions without the skill
+seam degrade silently.
+
+With `lazyTools: true`, the six tool schemas stay out of the system prompt until
+the skill is successfully invoked. Registration happens once and lasts until the
+plugin is unloaded. Repeated invocations do not register duplicate tools. Entering
+a resumed conversation whose history contains a successful skill invocation also
+registers the tools. Setting `lazyTools: false` registers them at plugin startup.
+
+## Observation subscriptions and routes
+
+- **Screenshot demand**: the client requests periodic screenshots while an observation view is
+  visible, using the PiP document's visibility when popped out. Hidden or collapsed views can
+  keep subscribing to state without requesting screenshots. The first screenshot subscriber
+  starts capture scheduling; the last one's departure cancels timers and skips queued captures.
+  An already running capture may finish. Demand applies to the service's owned sessions, not just
+  the selected session.
+- **Wire**: `GET /bsk-observation/events` is the live synchronization channel (SSE). Every connection,
+  including reconnects, starts with `{ type: "snapshot", sessions, available }`, followed by
+  `upsert`, `remove`, `reset`, and `availability` events on the same stream. Replace local state
+  with each snapshot before applying subsequent events. Use `?thumbnails=0` for state-only
+  subscriptions or `?thumbnails=1` to request screenshots; omitting the parameter defaults to
+  requesting screenshots for compatibility. Closing the stream releases its screenshot demand.
+  `GET /bsk-observation/state` remains a one-time `{ sessions, available }` read and does not
+  request screenshots. It has no ordering guarantee relative to a separate SSE connection;
+  live clients should initialize and resynchronize from the stream's snapshot instead.
+  The host also serves `POST /bsk-observation/interrupt`, `POST /bsk-observation/stop`, and
+  `GET /bsk-observation/thumbnail/<attachmentId>` through the dsh `webServer` route seam
+  (dsh 0.1's Typert Remote pipeline is closed to out-of-tree packages). All commands for one
+  session — tool calls and frame captures alike — run through a per-session FIFO, because the
+  daemon accepts only one unfinished command per session.
+- **Programmatic subscription**: `ObservationService.subscribe(listener, { thumbnails: false })`
+  subscribes to state without requesting screenshots. On an active service, the listener receives
+  the initial `snapshot` synchronously, before `subscribe` returns, then receives subsequent
+  changes. `thumbnails` defaults to `true`, so callers should choose it explicitly. The returned
+  unsubscribe function is safe to call repeatedly and releases this subscription's screenshot
+  demand. Subscribing after service disposal is a no-op.
+- **Trust model**: these routes expose live screenshots (and an interrupt write), so they
+  replicate the browser-trust fence dsh applies to its own `/api` routes: the request Host
+  must be a loopback authority (`localhost`, `127.0.0.0/8`, `[::1]`), a present Origin must
+  match the Host, `sec-fetch-site: cross-site` is refused, and POST requires an
+  `application/json` body (cross-site simple requests can never satisfy that). The channel is
+  therefore built for **loopback-only serving** — binding the dsh web server to `0.0.0.0` and
+  reaching it through a LAN address will (deliberately) fail the fence; do not put these
+  routes behind a non-loopback reverse proxy without adding your own authentication.
+
+## Tool results and cancellation
+
+- **Cancellation**: aborting a tool call (`exec.signal`) kills the underlying bsk child process,
+  matching BrowserSkill's cooperative tool-cancellation model.
+- **UI cards**: calls render as terminal cards (command line as title, output as the completed
+  card). Screenshots additionally attach the image itself when the host mounts an attachment store
+  and the active model route declares image input; otherwise the PNG path is returned.
+- **Web UI toolview (browser half)**: the package is dual-face. `dsh.client` (platform `web`) ships
+  `lib/client.cjs`, which registers a keyed `tool.call.toolview` view for `browser_inspect`. The
+  custom view keeps a terminal block for every inspect action and, when a screenshot result carries
+  an image block, resolves the durable attachment through the client session's authorized
+  `readAttachment` RPC and renders it with the shared `MessageImage` thumbnail/lightbox atoms.
+  The other five tools keep the stock terminal card. The bundle follows the dsh client
+  contract: a CJS closure factory handed to `window.__ModuleLoader__.load`, platform modules
+  (`react`, `dsh-client-ui-*`) external, everything else inlined, CSS Modules compiled by
+  lightningcss.
+- **Errors**: non-zero bsk exits surface the CLI's JSON error envelope (`code`, `message`, `hint`)
+  so the model gets the daemon's actionable guidance.
+- **Long-running work** (e.g. `bsk record`) is not backgrounded via `ctx.jobs` yet — tracked as a
+  follow-up.

packages/dsh-plugin-browserskill/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@wxg-prc-cpg/browser-skill-dsh-plugin",
   "description": "DeepSeek Harness tool plugin that exposes BrowserSkill browser automation (browser_* tools) to the model",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "license": "MIT",
   "publishConfig": {
     "access": "public",

packages/dsh-plugin-browserskill/src/runner.ts

@@ -5,7 +5,7 @@
  * map the CLI's JSON error envelope onto a thrown `BskError`.
  */
 
-import { type ChildProcess, spawn } from "node:child_process";
+import { type ChildProcess, type SpawnOptionsWithoutStdio, spawn } from "node:child_process";
 
 /** Shape of the JSON error envelope `bsk --json` prints on failure. */
 export interface BskErrorBody {
@@ -53,7 +53,11 @@ export interface BskRunOptions {
 }
 
 /** Minimal spawn signature so tests can substitute a fake child process. */
-export type SpawnImpl = (command: string, args: string[]) => ChildProcess;
+export type SpawnImpl = (
+  command: string,
+  args: string[],
+  options?: SpawnOptionsWithoutStdio,
+) => ChildProcess;
 
 export interface BskRunner {
   /** Run `bsk <args...> --json` and collect its output. */
@@ -64,29 +68,66 @@ export interface BskRunner {
   killFor(tag: string): number;
 }
 
-// Business RPCs translate SIGINT into the daemon's cancel(rpc_id) protocol.
-// Give that bounded reconciliation path time to settle before the hard kill.
+// Business RPCs translate Ctrl-C / opt-in stdin EOF into cancel(rpc_id).
+// Allow reconciliation before hard-killing an old or unresponsive CLI.
 const KILL_GRACE_MS = 3000;
+// Windows IPC may spend 5s connecting, 2s cancelling, 2s settling,
+// and up to 5s releasing the entire batch of caller-owned transfers.
+const WINDOWS_KILL_GRACE_MS = 15_000;
 const SESSION_BUSY_RETRY_DELAY_MS = 100;
 
 export function createBskRunner(bskPath: string, spawnImpl: SpawnImpl = spawn): BskRunner {
   const live = new Map<ChildProcess, string | undefined>();
+  const windows = process.platform === "win32";
+  const cancelling = new Set<ChildProcess>();
 
   function killChild(child: ChildProcess): void {
-    if (child.exitCode !== null || child.signalCode !== null) return;
-    child.kill("SIGINT");
-    const force = setTimeout(() => {
-      if (child.exitCode === null && child.signalCode === null) child.kill("SIGKILL");
-    }, KILL_GRACE_MS);
+    if (child.exitCode !== null || child.signalCode !== null || cancelling.has(child)) return;
+    cancelling.add(child);
+    // Node kills Windows children outright for SIGINT. EOF asks the CLI to
+    // send its existing cancel RPC and wait for browser reconciliation.
+    if (windows && child.stdin) child.stdin.end();
+    else child.kill("SIGINT");
+    const force = setTimeout(
+      () => {
+        if (child.exitCode === null && child.signalCode === null) child.kill("SIGKILL");
+      },
+      windows ? WINDOWS_KILL_GRACE_MS : KILL_GRACE_MS,
+    );
     force.unref();
+    child.once("close", () => {
+      clearTimeout(force);
+      cancelling.delete(child);
+    });
   }
 
   return {
     run(args, options = {}) {
+      if (options.signal?.aborted) {
+        return Promise.resolve({
+          code: null,
+          stdout: "",
+          stderr: "",
+          timedOut: false,
+          aborted: true,
+        });
+      }
       return new Promise<BskRunResult>((resolve, reject) => {
         let child: ChildProcess;
         try {
-          child = spawnImpl(bskPath, [...args, "--json"]);
+          child = spawnImpl(
+            bskPath,
+            [...args, "--json"],
+            windows
+              ? {
+                  windowsHide: true,
+                  env: { ...process.env, BSK_CANCEL_ON_STDIN_CLOSE: "1" },
+                }
+              : undefined,
+          );
+          // A child exiting while cancellation closes stdin may report EPIPE.
+          // Its close/error event remains the authority for the run result.
+          child.stdin?.on("error", () => {});
         } catch (error) {
           reject(error);
           return;

packages/dsh-plugin-browserskill/tests/runner.test.ts

@@ -1,6 +1,7 @@
 import type { ChildProcess } from "node:child_process";
 import { EventEmitter } from "node:events";
-import { describe, expect, it } from "vitest";
+import { PassThrough } from "node:stream";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import {
   type BskRunResult,
   createBskRunner,
@@ -92,6 +93,77 @@ describe("createBskRunner", () => {
   });
 });
 
+describe("Windows parent cancellation", () => {
+  const originalPlatform = Object.getOwnPropertyDescriptor(process, "platform")!;
+  beforeEach(() => Object.defineProperty(process, "platform", { value: "win32" }));
+  afterEach(() => {
+    Object.defineProperty(process, "platform", originalPlatform);
+    vi.useRealTimers();
+  });
+
+  it("opts in to stdin cancellation and waits for CLI reconciliation", async () => {
+    const child = Object.assign(new FakeChild(), { stdin: new PassThrough() });
+    const spawn = vi.fn(() => child as unknown as ChildProcess);
+    const runner = createBskRunner("bsk", spawn);
+    const abort = new AbortController();
+    const result = runner.run(["snapshot"], { signal: abort.signal });
+    expect(spawn.mock.calls[0]).toEqual([
+      "bsk",
+      ["snapshot", "--json"],
+      {
+        windowsHide: true,
+        env: { ...process.env, BSK_CANCEL_ON_STDIN_CLOSE: "1" },
+      },
+    ]);
+    abort.abort();
+    expect(child.stdin.writableEnded).toBe(true);
+    expect(child.killedWith).toEqual([]);
+    // Closing an already-exited child's pipe must not crash the host.
+    child.stdin.emit("error", Object.assign(new Error("closed"), { code: "EPIPE" }));
+    child.finish(2, '{"code":"cancelled"}');
+    expect(await result).toMatchObject({ code: 2, aborted: true });
+  });
+
+  it("bounds cancellation of an old or unresponsive CLI", async () => {
+    vi.useFakeTimers();
+    const child = Object.assign(new FakeChild(), { stdin: new PassThrough() });
+    const runner = createBskRunner("bsk", fakeSpawn([child]));
+    const result = runner.run(["snapshot"], { timeoutMs: 5 });
+    await vi.advanceTimersByTimeAsync(5);
+    expect(child.stdin.writableEnded).toBe(true);
+    expect(child.killedWith).toEqual([]);
+    await vi.advanceTimersByTimeAsync(10_000);
+    expect(child.killedWith).toEqual([]);
+    await vi.advanceTimersByTimeAsync(5_000);
+    expect(child.killedWith).toEqual(["SIGKILL"]);
+    expect(await result).toMatchObject({ timedOut: true });
+  });
+
+  it("cancels only the requested tag and clears the fallback after exit", async () => {
+    vi.useFakeTimers();
+    const a = Object.assign(new FakeChild(), { stdin: new PassThrough() });
+    const b = Object.assign(new FakeChild(), { stdin: new PassThrough() });
+    const runner = createBskRunner("bsk", fakeSpawn([a, b]));
+    const first = runner.run(["snapshot"], { tag: "a" });
+    const second = runner.run(["snapshot"], { tag: "b" });
+    expect(runner.killFor("a")).toBe(1);
+    expect(a.stdin.writableEnded).toBe(true);
+    expect(b.stdin.writableEnded).toBe(false);
+    a.finish(2);
+    b.finish(0);
+    await Promise.all([first, second]);
+    expect(vi.getTimerCount()).toBe(0);
+  });
+
+  it("does not start work for an already-aborted call", async () => {
+    const spawn = vi.fn();
+    const runner = createBskRunner("bsk", spawn);
+    const signal = AbortSignal.abort();
+    expect(await runner.run(["snapshot"], { signal })).toMatchObject({ aborted: true });
+    expect(spawn).not.toHaveBeenCalled();
+  });
+});
+
 describe("parseBskJson", () => {
   const base: BskRunResult = { code: 0, stdout: "", stderr: "", timedOut: false, aborted: false };
 

scripts/install-windows.test.ps1

@@ -0,0 +1,355 @@
+#Requires -Version 5.1
+param(
+    [string]$BskPath = (Join-Path $PSScriptRoot "../target/debug/bsk.exe"),
+    [switch]$HelpersOnly
+)
+$ErrorActionPreference = "Stop"
+
+# Load definitions without running Main. Registry PATH writes are isolated below.
+$installer = Join-Path $PSScriptRoot "../install.ps1"
+$tokens = $null
+$errors = $null
+$ast = [System.Management.Automation.Language.Parser]::ParseFile($installer, [ref]$tokens, [ref]$errors)
+if ($errors.Count) { throw ($errors | Out-String) }
+foreach ($statement in $ast.EndBlock.Statements) {
+    if ($statement -is [System.Management.Automation.Language.FunctionDefinitionAst]) {
+        $definition = $statement.Extent.Text
+        if ($statement.Name -eq "Add-ToUserPath") {
+            $definition = $definition.Replace('[Environment]::GetEnvironmentVariable("PATH", "User")', '$script:UserPath')
+            $definition = $definition.Replace('[Environment]::SetEnvironmentVariable("PATH", $newUserPath, "User")', '$script:UserPath = $newUserPath')
+        }
+        Invoke-Expression $definition
+    }
+}
+function Assert-Equal($Actual, $Expected) {
+    if ($Actual -cne $Expected) { throw "expected [$Expected], got [$Actual]" }
+}
+function Assert-Fails([scriptblock]$Action, [string]$MessageContains) {
+    $failed = $false
+    try { & $Action } catch {
+        $failed = $true
+        if ($MessageContains -and -not $_.Exception.Message.Contains($MessageContains)) { throw }
+    }
+    if (-not $failed) { throw "expected failure" }
+}
+
+# Isolate the fatal-error stub and restore the real process environment.
+& {
+    function Write-Die([string]$Message) { throw $Message }
+    $oldProcessArch = $env:PROCESSOR_ARCHITECTURE
+    $oldNativeArch = $env:PROCESSOR_ARCHITEW6432
+    try {
+        $cases = @(
+            @{ Process = 'AMD64'; Native = $null; Arch = 'x64'; Triple = 'x86_64-pc-windows-msvc' }
+            @{ Process = 'ARM64'; Native = $null; Arch = 'arm64'; Triple = 'aarch64-pc-windows-msvc' }
+            @{ Process = 'amd64'; Native = $null; Arch = 'x64'; Triple = 'x86_64-pc-windows-msvc' }
+            @{ Process = 'x86'; Native = 'AMD64'; Arch = 'x64'; Triple = 'x86_64-pc-windows-msvc' }
+            @{ Process = 'x86'; Native = 'ARM64'; Arch = 'arm64'; Triple = 'aarch64-pc-windows-msvc' }
+            @{ Process = $null; Native = 'AMD64'; Arch = 'x64'; Triple = 'x86_64-pc-windows-msvc' }
+            @{ Process = 'x86'; Native = $null; Error = 'unsupported architecture: x86 (x64 and ARM64 only)' }
+            @{ Process = 'AMD64'; Native = 'IA64'; Error = 'unsupported architecture: IA64 (x64 and ARM64 only)' }
+            @{ Process = $null; Native = $null; Error = 'could not detect Windows architecture: PROCESSOR_ARCHITEW6432 and PROCESSOR_ARCHITECTURE are empty' }
+        )
+        foreach ($case in $cases) {
+            $env:PROCESSOR_ARCHITECTURE = $case.Process
+            $env:PROCESSOR_ARCHITEW6432 = $case.Native
+            if ($case.Error) {
+                $message = $null
+                try { Get-PlatformTriple | Out-Null } catch { $message = $_.Exception.Message }
+                Assert-Equal $message $case.Error
+            }
+            else {
+                $platform = Get-PlatformTriple
+                Assert-Equal $platform.ArchId $case.Arch
+                Assert-Equal $platform.TargetTriple $case.Triple
+                Assert-Equal $platform.PlatformKey "windows-$($case.Arch)"
+            }
+        }
+        Write-Host "Windows installer architecture regressions passed ($($PSVersionTable.PSVersion))"
+    }
+    finally {
+        $env:PROCESSOR_ARCHITECTURE = $oldProcessArch
+        $env:PROCESSOR_ARCHITEW6432 = $oldNativeArch
+    }
+}
+$dir = 'C:\Users\Alice\.local\bin'
+$pathCases = @(
+    @{ Existing = ''; Expected = $dir }
+    @{ Existing = 'C:\WindowsApps'; Expected = "$dir;C:\WindowsApps" }
+    @{ Existing = 'C:\A;C:\B'; Expected = "$dir;C:\A;C:\B" }
+    @{ Existing = "C:\old-bsk;$dir;C:\B;$($dir.ToUpperInvariant())"; Expected = "$dir;C:\old-bsk;C:\B" }
+)
+$oldPath = $env:PATH
+try {
+    foreach ($case in $pathCases) {
+        $script:UserPath = $case.Existing
+        $env:PATH = $case.Existing
+        foreach ($attempt in 1..2) {
+            Add-ToUserPath $dir
+            Add-ToSessionPath $dir
+            Assert-Equal $script:UserPath $case.Expected
+            Assert-Equal $env:PATH $case.Expected
+        }
+    }
+} finally { $env:PATH = $oldPath }
+if ($HelpersOnly) {
+    Write-Host "Windows installer helper regressions passed ($($PSVersionTable.PSVersion))"
+    return
+}
+
+$root = Join-Path ([IO.Path]::GetTempPath()) ("bsk-install-test-" + [Guid]::NewGuid().ToString('N'))
+[IO.Directory]::CreateDirectory($root) | Out-Null
+$oldBskHome = $env:BSK_HOME
+$oldAutoUpdate = $env:BSK_AUTO_UPDATE
+$oldVersion = $env:BSK_VERSION
+$oldProcessArch = $env:PROCESSOR_ARCHITECTURE
+$oldNativeArch = $env:PROCESSOR_ARCHITEW6432
+$daemon = $null
+$script:DownloadServer = $null
+try {
+    $utf8 = New-Object System.Text.UTF8Encoding($false)
+    $bashRc = Join-Path $root ".bashrc"
+    $existing = "# existing 中文 configuration" + [char]10
+    [IO.File]::WriteAllText($bashRc, $existing, $utf8)
+    $special = 'C:\Users\张三 space $HOME $(echo unsafe) ! & [x] O''Brien\.local\bin'
+    Add-ToBashProfile $special $bashRc
+    $first = [IO.File]::ReadAllText($bashRc)
+    if (-not $first.StartsWith($existing)) { throw "existing bashrc content changed" }
+    if (-not $first.Contains('张三')) { throw "Unicode path was lost" }
+    Add-ToBashProfile $special $bashRc
+    Assert-Equal ([IO.File]::ReadAllText($bashRc)) $first
+    $bytes = [IO.File]::ReadAllBytes($bashRc)
+    if ($bytes[0] -eq 0xEF) { throw "unexpected UTF-8 BOM" }
+
+    $bash = [IO.Path]::GetFullPath((Join-Path (Split-Path (Get-Command git).Source -Parent) "../bin/bash.exe"))
+    if (-not (Test-Path -LiteralPath $bash)) { throw "Git Bash is required for quoting regression" }
+    $env:BSK_TEST_RC = $bashRc
+    $probe = Join-Path $root 'probe.sh'
+    [IO.File]::WriteAllText($probe, 'source "$BSK_TEST_RC"; printf "%s\n" "${PATH%%:*}"', $utf8)
+    $actual = & $bash --noprofile --norc $probe
+    if ($LASTEXITCODE -ne 0) { throw "Git Bash failed" }
+    Assert-Equal $actual ('/c' + $special.Substring(2).Replace('\', '/'))
+
+    $env:BSK_HOME = Join-Path $root "home [state]"
+    $env:BSK_AUTO_UPDATE = "off"
+    [IO.Directory]::CreateDirectory($env:BSK_HOME) | Out-Null
+    $sourceDir = Join-Path $root "download"
+    [IO.Directory]::CreateDirectory($sourceDir) | Out-Null
+    $source = Join-Path $sourceDir "bsk.exe"
+    [IO.File]::Copy((Resolve-Path -LiteralPath $BskPath).Path, $source)
+    $targetDir = Join-Path $root "中文 space [x] & install"
+    [IO.Directory]::CreateDirectory($targetDir) | Out-Null
+    $target = Join-Path $targetDir "bsk.exe"
+    $firstInstallOutput = Install-Binary $source $target 6>&1 | Out-String
+    if ($firstInstallOutput -match 'daemon will restart') { throw 'fresh install reported a daemon restart' }
+    Assert-Equal (Get-FileHash -LiteralPath $target).Hash (Get-FileHash -LiteralPath $source).Hash
+
+    $daemon = Start-Process -FilePath $target -ArgumentList @('daemon', 'start', '--foreground', '--port', '0') -WindowStyle Hidden -PassThru
+    $infoPath = Join-Path $env:BSK_HOME "daemon.json"
+    $deadline = [DateTime]::UtcNow.AddSeconds(15)
+    while (-not [IO.File]::Exists($infoPath)) {
+        if ($daemon.HasExited -or [DateTime]::UtcNow -gt $deadline) { throw "daemon failed to start" }
+        Start-Sleep -Milliseconds 50
+    }
+    # PE overlays distinguish old/new executables without another build.
+    $stream = [IO.File]::OpenWrite($source)
+    try {
+        $stream.Seek(0, [IO.SeekOrigin]::End) | Out-Null
+        $marker = $utf8.GetBytes("installer replacement regression")
+        $stream.Write($marker, 0, $marker.Length)
+    } finally { $stream.Dispose() }
+    Install-Binary $source $target
+    if (-not $daemon.WaitForExit(5000)) { throw "old daemon still running" }
+    Assert-Equal (Get-FileHash -LiteralPath $target).Hash (Get-FileHash -LiteralPath $source).Hash
+    & $target --version
+    if ($LASTEXITCODE -ne 0) { throw "replacement is not executable" }
+
+    # Installing into a new directory must also stop a daemon from the old one.
+    $newTargetDir = Join-Path $root "new install"
+    [IO.Directory]::CreateDirectory($newTargetDir) | Out-Null
+    $newTarget = Join-Path $newTargetDir "bsk.exe"
+    $before = (Get-FileHash -LiteralPath $target).Hash
+    $daemon = Start-Process -FilePath $target -ArgumentList @('daemon', 'start', '--foreground', '--port', '0') -WindowStyle Hidden -PassThru
+    $deadline = [DateTime]::UtcNow.AddSeconds(15)
+    while (-not [IO.File]::Exists($infoPath)) {
+        if ($daemon.HasExited -or [DateTime]::UtcNow -gt $deadline) { throw "old-directory daemon failed to start" }
+        Start-Sleep -Milliseconds 50
+    }
+    Install-Binary $source $newTarget
+    if (-not $daemon.WaitForExit(5000)) { throw "new-directory install left the old daemon running" }
+    Assert-Equal (Get-FileHash -LiteralPath $target).Hash $before
+    Assert-Equal (Get-FileHash -LiteralPath $newTarget).Hash (Get-FileHash -LiteralPath $source).Hash
+    & $newTarget --version
+    if ($LASTEXITCODE -ne 0) { throw "new-directory installation is not executable" }
+    if (@(Get-ChildItem -LiteralPath $newTargetDir -Filter "*.install-*").Count) { throw "new-directory staging files leaked" }
+
+    # Refuse replacement when daemon identity cannot be verified.
+    [IO.File]::WriteAllText($infoPath, 'invalid daemon metadata')
+    $before = (Get-FileHash -LiteralPath $target).Hash
+    Assert-Fails { Install-Binary $source $target } -MessageContains $infoPath
+    Assert-Equal (Get-FileHash -LiteralPath $target).Hash $before
+
+    # A failed stop must also prevent installation to a previously empty target.
+    $blockedTarget = Join-Path $newTargetDir "blocked.exe"
+    Assert-Fails { Install-Binary $source $blockedTarget } -MessageContains $infoPath
+    if (Test-Path -LiteralPath $blockedTarget) { throw "failed stop created an installation" }
+    if (@(Get-ChildItem -LiteralPath $newTargetDir -Filter "*.install-*").Count) { throw "failed stop leaked staging files" }
+    Assert-Equal ([IO.File]::ReadAllText($infoPath)) 'invalid daemon metadata'
+    # Following the reported recovery path must allow the same installation to succeed.
+    [IO.File]::Delete($infoPath)
+    Install-Binary $source $blockedTarget
+    Assert-Equal (Get-FileHash -LiteralPath $blockedTarget).Hash (Get-FileHash -LiteralPath $source).Hash
+
+    # A remaining lock must fail without truncation or staging debris.
+    $lock = [IO.File]::Open($target, [IO.FileMode]::Open, [IO.FileAccess]::Read, [IO.FileShare]::None)
+    try { Assert-Fails { Install-Binary $source $target } } finally { $lock.Dispose() }
+    Assert-Equal (Get-FileHash -LiteralPath $target).Hash $before
+    if (@(Get-ChildItem -LiteralPath $targetDir -Filter "*.install-*").Count) { throw "staging files leaked" }
+
+    # Exercise Main with real ZIPs/executables, isolating network and user state.
+    & {
+        $fixtureTemp = Join-Path $root 'temp [literal]'
+        [IO.Directory]::CreateDirectory($fixtureTemp) | Out-Null
+        $mainDefinition = ($ast.EndBlock.Statements | Where-Object {
+            $_ -is [System.Management.Automation.Language.FunctionDefinitionAst] -and $_.Name -eq 'Main'
+        }).Extent.Text.Replace('[System.IO.Path]::GetTempPath()', '$fixtureTemp')
+        Invoke-Expression $mainDefinition
+        function Write-Die([string]$Message) { throw $Message }
+        $bashProfile = (Get-Command Add-ToBashProfile).ScriptBlock
+        function Add-ToBashProfile([string]$Dir) {
+            & $bashProfile $Dir (Join-Path $root 'flow.bashrc')
+        }
+        $fixtureArchive = Join-Path $root 'release.zip'
+        Compress-Archive -LiteralPath $source -DestinationPath $fixtureArchive -CompressionLevel Fastest
+        # Serve the ZIP over loopback HTTP. Only the URL is redirected below;
+        # Invoke-WebRequest and the installer's disk writes remain real.
+        $script:DownloadServer = Start-Job -ArgumentList $fixtureArchive -ScriptBlock {
+            param($Archive)
+            $ErrorActionPreference = 'Stop'
+            $body = [IO.File]::ReadAllBytes($Archive)
+            $listener = [Net.Sockets.TcpListener]::new([Net.IPAddress]::Loopback, 0)
+            try {
+                $listener.Start()
+                Write-Output $listener.LocalEndpoint.Port
+                while ($true) {
+                    if (-not $listener.Pending()) { Start-Sleep -Milliseconds 50; continue }
+                    $client = $listener.AcceptTcpClient()
+                    try {
+                        $stream = $client.GetStream()
+                        $stream.ReadTimeout = 5000
+                        $stream.WriteTimeout = 5000
+                        $reader = [IO.StreamReader]::new($stream)
+                        while (($line = $reader.ReadLine()) -and $line.Length) { }
+                        $header = [Text.Encoding]::ASCII.GetBytes("HTTP/1.1 200 OK`r`nContent-Type: application/octet-stream`r`nContent-Length: $($body.Length)`r`nConnection: close`r`n`r`n")
+                        $stream.Write($header, 0, $header.Length)
+                        $stream.Write($body, 0, $body.Length)
+                    } finally { $client.Dispose() }
+                }
+            } finally { $listener.Stop() }
+        }
+        $serverPort = $null
+        $deadline = [DateTime]::UtcNow.AddSeconds(15)
+        while (-not $serverPort) {
+            $serverPort = Receive-Job $script:DownloadServer
+            if ($script:DownloadServer.State -ne 'Running' -or [DateTime]::UtcNow -gt $deadline) {
+                throw 'download fixture failed to start'
+            }
+            if (-not $serverPort) { Start-Sleep -Milliseconds 50 }
+        }
+        $asset = @{ sha256 = (Get-FileHash -LiteralPath $fixtureArchive).Hash }
+        $fixtureManifest = @{ version = '9.8.7'; assets = @{ 'windows-x64' = $asset } }
+        $downloads = New-Object 'System.Collections.Generic.List[string]'
+        function Invoke-RestMethod([string]$Uri) {
+            if (-not $fixtureManifest) { throw 'fixture manifest unavailable' }
+            return $fixtureManifest
+        }
+        function Invoke-WebRequest {
+            [CmdletBinding()]
+            param([string]$Uri, [string]$OutFile, [switch]$UseBasicParsing)
+            $downloads.Add($Uri)
+            $PSBoundParameters['Uri'] = "http://127.0.0.1:$serverPort/release.zip"
+            Microsoft.PowerShell.Utility\Invoke-WebRequest @PSBoundParameters -TimeoutSec 15
+        }
+        $GitHub = 'https://example.invalid/fixture'
+        $InstallDir = Join-Path $root 'installed [literal]'
+        $installed = Join-Path $InstallDir 'bsk.exe'
+        $env:BSK_VERSION = $null
+        $env:PROCESSOR_ARCHITECTURE = 'AMD64'
+        $env:PROCESSOR_ARCHITEW6432 = $null
+        $script:UserPath = "$targetDir;$InstallDir;$($InstallDir.ToUpperInvariant())"
+        $env:PATH = "$targetDir;$InstallDir;$oldPath"
+        Assert-Equal (Get-Command bsk).Source $target
+        $installOutput = Main 6>&1 | Out-String
+        if ($installOutput -notmatch 'current session only' -or
+            $installOutput -notmatch 'Machine PATH' -or $installOutput -notmatch 'Get-Command bsk -All') {
+            throw 'install did not explain PATH verification in a new terminal'
+        }
+        Assert-Equal $downloads.Count 1
+        Assert-Equal (Get-Command bsk).Source $installed
+        Assert-Equal $script:UserPath "$InstallDir;$targetDir"
+        Assert-Equal (Get-FileHash -LiteralPath $installed).Hash (Get-FileHash -LiteralPath $source).Hash
+        Assert-Equal @(Get-ChildItem -LiteralPath $fixtureTemp -Force).Count 0
+
+        # ARM64 must be listed in the manifest before any archive is requested.
+        $env:PROCESSOR_ARCHITECTURE = 'ARM64'
+        $downloads.Clear()
+        $message = $null
+        try { Main } catch { $message = $_.Exception.Message }
+        Assert-Equal $message 'version.json does not list a Windows ARM64 package for bsk 9.8.7'
+        Assert-Equal $downloads.Count 0
+        $env:BSK_VERSION = '9.8.7'
+        $fixtureManifest = $null
+        $message = $null
+        try { Main } catch { $message = $_.Exception.Message }
+        Assert-Equal $message 'version.json does not list a Windows ARM64 package for bsk 9.8.7'
+        Assert-Equal $downloads.Count 0
+
+        # Keep pinned x64 installs compatible with older releases without manifests.
+        $env:PROCESSOR_ARCHITECTURE = 'AMD64'
+        Main
+        Assert-Equal $downloads.Count 1
+        Assert-Equal @(Get-ChildItem -LiteralPath $fixtureTemp -Force).Count 0
+
+        # A listed ARM64 archive remains selectable (the fixture uses the host EXE).
+        $fixtureManifest = @{ version = '9.8.7'; assets = @{ 'windows-arm64' = $asset } }
+        $env:PROCESSOR_ARCHITECTURE = 'ARM64'
+        Main
+        Assert-Equal $downloads[$downloads.Count - 1] "$GitHub/releases/download/cli-v9.8.7/bsk-v9.8.7-aarch64-pc-windows-msvc.zip"
+
+        # A checksum failure must clean the bracketed temp path and preserve the install.
+        $before = (Get-FileHash -LiteralPath $installed).Hash
+        $fixtureManifest.assets['windows-arm64'] = @{ sha256 = '0' * 64 }
+        Assert-Fails { Main }
+        Assert-Equal (Get-FileHash -LiteralPath $installed).Hash $before
+        Assert-Equal @(Get-ChildItem -LiteralPath $fixtureTemp -Force).Count 0
+    }
+    Write-Host "Windows installer regressions passed ($($PSVersionTable.PSVersion))"
+}
+catch {
+    Write-Host ($_ | Out-String)
+    Write-Host $_.ScriptStackTrace
+    throw
+}
+finally {
+    if ($script:DownloadServer) {
+        Stop-Job $script:DownloadServer
+        Remove-Job $script:DownloadServer
+    }
+    if ($daemon -and -not $daemon.HasExited) {
+        Stop-Process -Id $daemon.Id -Force
+        $daemon.WaitForExit(5000) | Out-Null
+    }
+    $env:BSK_HOME = $oldBskHome
+    $env:BSK_AUTO_UPDATE = $oldAutoUpdate
+    $env:BSK_VERSION = $oldVersion
+    $env:PROCESSOR_ARCHITECTURE = $oldProcessArch
+    $env:PROCESSOR_ARCHITEW6432 = $oldNativeArch
+    $env:PATH = $oldPath
+    Remove-Item Env:BSK_TEST_RC -ErrorAction SilentlyContinue
+    # Resolve and verify before recursive cleanup; only this fixture is removed.
+    $resolvedRoot = [IO.Path]::GetFullPath($root)
+    $tempRoot = [IO.Path]::GetFullPath([IO.Path]::GetTempPath()).TrimEnd('\') + '\'
+    if (-not $resolvedRoot.StartsWith($tempRoot, [StringComparison]::OrdinalIgnoreCase) -or
+        -not ([IO.Path]::GetFileName($resolvedRoot)).StartsWith('bsk-install-test-')) { throw "invalid cleanup path" }
+    Remove-Item -LiteralPath $resolvedRoot -Recurse -Force
+}

scripts/release.mjs

@@ -174,16 +174,22 @@ function updateChangelog(version) {
 
   const today = new Date().toISOString().slice(0, 10);
   const escapedVer = version.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+  const versionHeading = new RegExp(`^## \\[${escapedVer}\\](?:\\s|$)`, "m");
 
   // First: fill in any date-placeholder line for this version (e.g. "## [0.2.0] - 2026-09-XX")
   const versionPlaceholder = new RegExp(`^## \\[${escapedVer}\\]\\s*-\\s*\\d{4}-\\d{2}-XX`, "m");
   if (versionPlaceholder.test(content)) {
     content = content.replace(versionPlaceholder, `## [${version}] - ${today}`);
-  } else {
-    // Otherwise: insert a new section after [Unreleased]
+  } else if (!versionHeading.test(content)) {
+    // Preserve prepared release entries; new versions go before the release history.
+    const heading = `## [${version}] - ${today}`;
     const unreleased = /^## \[Unreleased\]/m;
     if (unreleased.test(content)) {
-      content = content.replace(unreleased, `## [Unreleased]\n\n## [${version}] - ${today}`);
+      content = content.replace(unreleased, `## [Unreleased]\n\n${heading}`);
+    } else if (/^## /m.test(content)) {
+      content = content.replace(/^## /m, `${heading}\n\n## `);
+    } else {
+      content = `${content.trimEnd()}\n\n${heading}\n`;
     }
   }