fix(geometry): normalize snapshot layout bounds and scroll together

Release/0.2.1

.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/tools/__tests__/frame-geometry.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it, vi } from "vitest";
-import { resolveFrameProjection, resolveNodeGeometry } from "../frame-geometry";
+import { resolveNodeGeometry } from "../frame-geometry";
 import {
   clipPolygon,
   polygonArea,
@@ -10,6 +10,7 @@ import {
   rectPolygon,
   regionBounds,
 } from "../geometry";
+import { GeometryContext } from "../geometry/frame-context";
 import type { CdpRunner } from "../shared";
 
 describe("frame geometry projection", () => {
@@ -82,28 +83,24 @@ describe("frame geometry projection", () => {
         throw new Error(`unexpected child command ${method}`);
       }) as CdpRunner["sendToTarget"],
     };
-    const projection = await resolveFrameProjection(
-      cdp,
-      {
-        rootFrameId: "main",
-        frames: [
-          { frameId: "main", target: { tabId: 4 } },
-          {
-            frameId: "same-process-parent",
-            parentFrameId: "main",
-            ownerBackendNodeId: 10,
-            target: { tabId: 4 },
-          },
-          {
-            frameId: "oopif",
-            parentFrameId: "same-process-parent",
-            ownerBackendNodeId: 20,
-            target: { tabId: 4, sessionId: "oopif-session" },
-          },
-        ],
-      },
-      "oopif",
-    );
+    const projection = await new GeometryContext(cdp, 4, {
+      rootFrameId: "main",
+      frames: [
+        { frameId: "main", target: { tabId: 4 } },
+        {
+          frameId: "same-process-parent",
+          parentFrameId: "main",
+          ownerBackendNodeId: 10,
+          target: { tabId: 4 },
+        },
+        {
+          frameId: "oopif",
+          parentFrameId: "same-process-parent",
+          ownerBackendNodeId: 20,
+          target: { tabId: 4, sessionId: "oopif-session" },
+        },
+      ],
+    }).targetProjection("oopif");
 
     expect(projection?.edges).toEqual([
       {

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

@@ -0,0 +1,464 @@
+import { describe, expect, it, vi } from "vitest";
+import type { CdpFrameGraph } from "@/browser-driver/frame-graph";
+import { resolveNodeGeometry } from "../frame-geometry";
+import { rectPolygon } from "../geometry";
+import {
+  projectSnapshotRect,
+  screenshotPageRect,
+  snapshotCoordinates,
+  snapshotViewportRect,
+} from "../geometry/coordinate-types";
+import { GeometryContext, snapshotLayoutScale } from "../geometry/frame-context";
+import type { CdpRunner } from "../shared";
+
+const target = { tabId: 4 };
+const graph: CdpFrameGraph = {
+  rootFrameId: "main",
+  frames: [
+    { frameId: "main", target },
+    { frameId: "child", parentFrameId: "main", ownerBackendNodeId: 10, target },
+  ],
+};
+
+function driver() {
+  const send = vi.fn(async (_tab: number, method: string): Promise<object> => {
+    if (method === "Page.getLayoutMetrics")
+      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" } };
+    if (method === "Runtime.callFunctionOn")
+      return { result: { value: { width: 300, height: 200 } } };
+    if (method === "Runtime.releaseObject") return {};
+    throw new Error(method);
+  });
+  return { send: send as CdpRunner["send"], getFrameGraph: vi.fn(async () => graph), calls: send };
+}
+
+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);
+    const results = await Promise.all(
+      Array.from({ length: 20 }, () => context.targetProjection("child")),
+    );
+    expect(results.every((value) => value === results[0])).toBe(true);
+    expect(cdp.getFrameGraph).toHaveBeenCalledTimes(1);
+    expect(cdp.calls.mock.calls.map(([, method]) => method)).toEqual([
+      "Page.getLayoutMetrics",
+      "DOM.getBoxModel",
+    ]);
+    await new GeometryContext(cdp, 4).targetProjection("child");
+    expect(cdp.getFrameGraph).toHaveBeenCalledTimes(2);
+    expect(cdp.calls.mock.calls).toHaveLength(4);
+  });
+
+  it("projects frame-local snapshot CSS bounds through the scaled owner content quad", async () => {
+    const cdp = driver();
+    const context = new GeometryContext(cdp, 4);
+    const source = { target, frameId: "child" };
+    const projection = await context.snapshotProjection(source, 10, [], {
+      width: 1000,
+      height: 1000,
+    });
+    if (projection.status !== "available") throw new Error("expected available projection");
+    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, {
+      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(
+      1,
+    );
+    expect(
+      cdp.calls.mock.calls.filter(([, method]) => method === "Runtime.releaseObject"),
+    ).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" },
+      { layoutUnitsPerCssPixel: 1, scrollCss: { x: 10, y: 20 } },
+    )!;
+    const projection = {
+      source: { target, frameId: "main" },
+      geometry: { sourceClips: [], edges: [], topViewport: { width: 800, height: 600 } },
+    };
+    expect(projectSnapshotRect(input, projection)).toEqual({
+      x: 20,
+      y: 30,
+      width: 120,
+      height: 40,
+    });
+    expect(
+      projectSnapshotRect(input, { ...projection, source: { target, frameId: "other" } }),
+    ).toBeNull();
+    expect(
+      projectSnapshotRect(input, {
+        ...projection,
+        source: { target: { tabId: 5 }, frameId: "main" },
+      }),
+    ).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 () => {
+    const cdp: CdpRunner = {
+      send: vi.fn(async () => ({
+        model: { border: [0, 0, 100, 0, 100, 100, 0, 100] },
+      })) as CdpRunner["send"],
+    };
+    expect(
+      await new GeometryContext(cdp, 4).snapshotProjection({ target, frameId: "child" }, 10, [], {
+        width: 100,
+        height: 100,
+      }),
+    ).toEqual({
+      status: "unavailable",
+      source: { target, frameId: "child" },
+      ownerBackendNodeId: 10,
+    });
+  });
+
+  it("keeps ancestor clips in target coordinates instead of applying nested offsets twice", async () => {
+    const cdp = driver();
+    const projection = await new GeometryContext(cdp, 4).snapshotProjection(
+      { target, frameId: "nested" },
+      10,
+      [rectPolygon({ x: 60, y: 620, w: 100, h: 100 })],
+      { width: 1000, height: 1000 },
+    );
+    if (projection.status !== "available") throw new Error("expected available projection");
+    const input = snapshotViewportRect(
+      [0, 0, 300, 200],
+      { target, frameId: "nested" },
+      { layoutUnitsPerCssPixel: 1, scrollCss: { x: 0, y: 0 } },
+    );
+    expect(projectSnapshotRect(input!, projection.projection)).toEqual({
+      x: 60,
+      y: 620,
+      width: 100,
+      height: 100,
+    });
+  });
+
+  it("rejects malformed frame ancestry without looping", async () => {
+    const cdp = driver();
+    const cycle: CdpFrameGraph = {
+      rootFrameId: "a",
+      frames: [
+        { frameId: "a", parentFrameId: "b", target },
+        { frameId: "b", parentFrameId: "a", target },
+      ],
+    };
+    expect(await new GeometryContext(cdp, 4, cycle).targetProjection("a")).toBeNull();
+    expect(cdp.calls).not.toHaveBeenCalled();
+    const orphan: CdpFrameGraph = {
+      rootFrameId: "a",
+      frames: [{ frameId: "a", parentFrameId: "missing", target }],
+    };
+    expect(await new GeometryContext(cdp, 4, orphan).targetProjection("a")).toBeNull();
+  });
+
+  it("rejects a live node whose frame belongs to another target before any DOM input", async () => {
+    const cdp = driver();
+    expect(
+      await resolveNodeGeometry(
+        cdp,
+        4,
+        { target: { tabId: 4, sessionId: "wrong" }, frameId: "child", backendNodeId: 20 },
+        { scrollIntoView: true },
+      ),
+    ).toMatchObject({ code: "cdp_failed" });
+    expect(cdp.calls).not.toHaveBeenCalled();
+  });
+
+  it("bounds concurrent measurements and does not dispatch queued reads after cancellation", async () => {
+    let active = 0;
+    let peak = 0;
+    const release: Array<() => void> = [];
+    const send = vi.fn(async () => {
+      active++;
+      peak = Math.max(peak, active);
+      await new Promise<void>((resolve) => release.push(resolve));
+      active--;
+      return {
+        visualViewport: { clientWidth: 1000 },
+        cssVisualViewport: { clientWidth: 1000 },
+        cssLayoutViewport: { clientWidth: 100, clientHeight: 100 },
+      };
+    });
+    const controller = new AbortController();
+    const context = new GeometryContext(
+      { send: send as CdpRunner["send"] },
+      4,
+      undefined,
+      controller.signal,
+    );
+    const tasks = Array.from({ length: 8 }, (_, index) =>
+      context.viewport({ tabId: 4, sessionId: String(index) }),
+    );
+    const settled = Promise.allSettled(tasks);
+    expect(send).toHaveBeenCalledTimes(4);
+    controller.abort();
+    for (const done of release) done();
+    const results = await settled;
+    expect(peak).toBe(4);
+    expect(send).toHaveBeenCalledTimes(4);
+    expect(results.filter((item) => item.status === "rejected")).toHaveLength(4);
+  });
+
+  it("releases an owner object even when cancellation arrives before its viewport read", async () => {
+    const controller = new AbortController();
+    const cdp = driver();
+    const original = cdp.calls.getMockImplementation()!;
+    cdp.calls.mockImplementation(async (tab, method) => {
+      const result = await original(tab, method);
+      if (method === "DOM.resolveNode") controller.abort();
+      return result;
+    });
+    const context = new GeometryContext(cdp, 4, undefined, controller.signal);
+    await expect(
+      context.snapshotProjection({ target, frameId: "child" }, 10, [], {
+        width: 1000,
+        height: 1000,
+      }),
+    ).rejects.toMatchObject({ name: "AbortError" });
+    expect(cdp.calls.mock.calls.map(([, method]) => method)).toEqual([
+      "DOM.getBoxModel",
+      "DOM.resolveNode",
+      "Runtime.releaseObject",
+    ]);
+  });
+
+  it("reads live owner geometry only after scrolling", async () => {
+    const cdp = driver();
+    const original = cdp.calls.getMockImplementation()!;
+    let scrolled = false;
+    cdp.calls.mockImplementation(async (tab, method) => {
+      if (method === "DOM.scrollIntoViewIfNeeded") {
+        scrolled = true;
+        return {};
+      }
+      if (method === "DOM.getContentQuads") {
+        expect(scrolled).toBe(true);
+        return { quads: [[60, 620, 100, 620, 100, 640, 60, 640]] };
+      }
+      if (method === "DOM.getBoxModel") expect(scrolled).toBe(true);
+      return original(tab, method);
+    });
+    expect(
+      await resolveNodeGeometry(
+        cdp,
+        4,
+        { target, frameId: "child", backendNodeId: 20 },
+        { scrollIntoView: true },
+      ),
+    ).toMatchObject({ topBounds: { x: 60, y: 620, width: 40, height: 20 } });
+    expect(cdp.getFrameGraph).toHaveBeenCalledTimes(1);
+    expect(cdp.calls.mock.calls.filter(([, method]) => method === "DOM.getBoxModel")).toHaveLength(
+      1,
+    );
+  });
+
+  it("adapts viewport CSS bounds to page DIP with scroll and browser zoom, never raster DPR", () => {
+    const viewport = { width: 1600, height: 1000, scrollX: 10, scrollY: 100, cssToDip: 0.9 };
+    const clip = screenshotPageRect({ x: 20, y: 30, width: 120, height: 40 }, viewport);
+    expect(clip).toEqual({ space: "page-dip", rect: { x: 27, y: 117, width: 108, height: 36 } });
+    expect(
+      screenshotPageRect({ x: 20, y: 30, width: 120, height: 40 }, { ...viewport, cssToDip: NaN }),
+    ).toBeNull();
+    expect(
+      screenshotPageRect({ x: 20, y: 30, width: 120, height: 40 }, { ...viewport, cssToDip: 0 }),
+    ).toBeNull();
+  });
+
+  it("retries a rejected measurement only in a new operation", async () => {
+    const cdp = driver();
+    cdp.calls.mockRejectedValueOnce(new Error("unavailable"));
+    const context = new GeometryContext(cdp, 4);
+    await expect(context.viewport(target)).rejects.toThrow("unavailable");
+    await expect(context.viewport(target)).rejects.toThrow("unavailable");
+    expect(cdp.calls).toHaveBeenCalledTimes(1);
+    expect(await new GeometryContext(cdp, 4).viewport(target)).toEqual({
+      width: 1000,
+      height: 1000,
+    });
+  });
+});

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

@@ -65,7 +65,11 @@ 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);
@@ -266,7 +270,15 @@ describe("handleScreenshot", () => {
     expect(sent.find((c) => c.method === "Page.captureScreenshot")).toBeUndefined();
   });
 
-  it("captures a clipped PNG when ref is given", async () => {
+  it.each([
+    { zoom: 1, scroll: 0, expected: { x: 10, y: 20, width: 100, height: 40 } },
+    { zoom: 0.9, scroll: 100, expected: { x: 9, y: 108, width: 90, height: 36 } },
+    { zoom: 1.25, scroll: 100, expected: { x: 12.5, y: 150, width: 125, height: 50 } },
+  ])("captures a ref in page DIP at zoom $zoom and scroll $scroll", async ({
+    zoom,
+    scroll,
+    expected,
+  }) => {
     const sm = new SessionManager({ agentWindow: fakeAgentWindow([100]) });
     const ctx = await sm.start("aa11");
     ctx.refStore.set("e5", 999, { tabId: 7 });
@@ -274,6 +286,10 @@ describe("handleScreenshot", () => {
       "DOM.scrollIntoViewIfNeeded": () => ({}),
       "DOM.getContentQuads": () => ({ quads: [[10, 20, 110, 20, 110, 60, 10, 60]] }),
       "Page.captureScreenshot": () => ({ data: TINY_PNG }),
+      "Page.getLayoutMetrics": () => ({
+        cssLayoutViewport: { clientWidth: 1280, clientHeight: 720, pageX: 0, pageY: scroll },
+        cssVisualViewport: { zoom },
+      }),
     });
     const captureVisibleTab = vi.fn();
     const res = await handleScreenshot(
@@ -297,7 +313,8 @@ describe("handleScreenshot", () => {
         clip?: { x: number; y: number; width: number; height: number };
       }
     )?.clip;
-    expect(clip).toMatchObject({ x: 10, y: 20, width: 100, height: 40 });
+    expect(clip).toMatchObject(expected);
+    expect(sent.filter((c) => c.method === "Page.getLayoutMetrics")).toHaveLength(1);
   });
 
   it("returns not_found for unknown ref", async () => {
@@ -2481,7 +2498,11 @@ 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");
@@ -2568,7 +2589,11 @@ 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") {
@@ -2659,7 +2684,11 @@ 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") {
@@ -2753,7 +2782,11 @@ 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") {
@@ -2918,7 +2951,11 @@ 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") {
@@ -3131,10 +3168,14 @@ describe("handleSnapshot", () => {
   }
 
   const VP_METRICS = {
+    visualViewport: { clientWidth: 1000 },
+    cssVisualViewport: { clientWidth: 1000 },
     cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 0, pageY: 0 },
   };
 
-  function makeFrameAwareDeps() {
+  function makeFrameAwareDeps(
+    ownerGeometry: "unavailable" | "available" | "clipped" = "unavailable",
+  ) {
     const strings = ["html", "body", "iframe", "button", "title", "Remote", "static", "auto"];
     const i = (value: string) => strings.indexOf(value);
     const styles = [i("static"), i("auto"), i("auto")];
@@ -3142,6 +3183,8 @@ describe("handleSnapshot", () => {
       strings,
       documents: [
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "main",
           nodes: {
             parentIndex: [-1, 0, 1],
@@ -3162,6 +3205,8 @@ describe("handleSnapshot", () => {
           },
         },
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           frameId: "child",
           nodes: {
             parentIndex: [-1, 0, 1],
@@ -3214,6 +3259,16 @@ describe("handleSnapshot", () => {
     ];
     const send = vi.fn(async (_tabId: number, method: string) => {
       if (method === "Page.getLayoutMetrics") return VP_METRICS;
+      if (ownerGeometry !== "unavailable") {
+        if (method === "DOM.getBoxModel") {
+          const x = ownerGeometry === "clipped" ? 10000 : 100;
+          return { model: { content: [x, 100, x + 400, 100, x + 400, 400, x, 400] } };
+        }
+        if (method === "DOM.resolveNode") return { object: { objectId: "owner" } };
+        if (method === "Runtime.callFunctionOn")
+          return { result: { value: { width: 400, height: 300 } } };
+        if (method === "Runtime.releaseObject") return {};
+      }
       if (method === "DOMSnapshot.enable" || method === "Accessibility.enable") return {};
       if (method === "DOMSnapshot.captureSnapshot") return snapshot;
       if (method === "Accessibility.getFullAXTree") return { nodes: mainAx };
@@ -3454,6 +3509,43 @@ describe("handleSnapshot", () => {
     expect(result.text).toContain("•••");
   });
 
+  it.each([
+    undefined,
+    100,
+    0,
+  ])("reports unavailable iframe geometry within the observation budget %s", async (maxTokens) => {
+    const result = await captureVomObservation(makeFrameAwareDeps().cdp, 4, "https://example.com", {
+      maxTokens,
+    });
+    expect(result.text.match(/@warning/g)).toHaveLength(1);
+    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 },
+      });
+    }
+    if (maxTokens === 100) expect(Math.ceil(result.text.length / 4)).toBeLessThanOrEqual(maxTokens);
+  });
+
+  it.each([
+    "available",
+    "clipped",
+  ] as const)("does not report successful %s geometry as an observation failure", async (ownerGeometry) => {
+    const result = await captureVomObservation(
+      makeFrameAwareDeps(ownerGeometry).cdp,
+      4,
+      "https://example.com",
+    );
+    expect(result.text).not.toContain("@warning");
+    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 });
+  });
+
   it("keeps frames and rendered refs on the same frame identity", async () => {
     const deps = makeFrameAwareDeps();
 

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

@@ -0,0 +1,237 @@
+// @vitest-environment node
+import { describe, expect, it } from "vitest";
+import type { CdpFrame, CdpFrameGraph, CdpTarget } from "@/browser-driver/frame-graph";
+import { GeometryContext } from "../geometry/frame-context";
+import type { CdpRunner } from "../shared";
+import { captureViewModel } from "../vom/capture";
+import { captureFrameData } from "../vom/frame-capture";
+
+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 = { probe: Rect; owners: Record<string, { x: number; y: number; scale: number }> };
+
+// 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 box = document.querySelector('#probe').getBoundingClientRect();
+  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 { probe: { x: box.x, y: box.y, w: box.width, h: box.height }, 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 },
+  ])("matches DOM geometry at device scale $deviceScale and zoom $zoom", async (configuration) => {
+    const evalRoot = new URL("../../../../../evals/browser/", import.meta.url);
+    const { createEvalServer } = await import(new URL("lib/server.mjs", evalRoot).href);
+    const { withChrome } = await import(
+      new URL("cases/regression/snapshot-coordinates/chrome.mjs", evalRoot).href
+    );
+    const server = createEvalServer();
+    const { baseUrl } = await server.start();
+    try {
+      await withChrome(
+        { executable: process.env.BSK_GEOMETRY_CHROME, ...configuration },
+        async (send: Send) => {
+          const { targetId } = await send<{ targetId: string }>("Target.createTarget", {
+            url: "about:blank",
+          });
+          const { sessionId: rootSession } = await send<{ sessionId: string }>(
+            "Target.attachToTarget",
+            { targetId, flatten: true },
+          );
+          await send(
+            "Page.navigate",
+            { url: `${baseUrl}/snapshot-coordinates?run=coordinates` },
+            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(2); // The cross-site fixture must actually be an OOPIF.
+          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(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}`);
+              return send(method, params, sessionFor(target));
+            },
+            getFrameGraph: async () => graph,
+          };
+          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 geometry = new GeometryContext(cdp, 1, graph);
+          const captured = await captureViewModel(cdp, 1, { geometry });
+          await captureFrameData(cdp, 1, captured, undefined, geometry);
+          expect(captured.frameGeometryIssues).toEqual([]);
+          for (const frame of frames) {
+            const node = captured.frameNodes
+              ?.get(frame.frameId)
+              ?.find((node) => node.attrs.id === "probe");
+            expect(node, `missing probe in ${names.get(frame.frameId) || "root"}`).toBeDefined();
+            const local = oracles.get(frame.frameId)!.probe;
+            const top = { ...local };
+            let current = frame;
+            while (current.parentFrameId) {
+              const owner = oracles.get(current.parentFrameId)!.owners[names.get(current.frameId)!];
+              top.x = owner.x + top.x * owner.scale;
+              top.y = owner.y + top.y * owner.scale;
+              top.w *= owner.scale;
+              top.h *= owner.scale;
+              current = frames.find((item) => item.frameId === current.parentFrameId)!;
+            }
+            expect(
+              node!.rect,
+              JSON.stringify({
+                frame: names.get(frame.frameId),
+                local,
+                top,
+                viewport: captured.viewport,
+              }),
+            ).not.toBeNull();
+            for (const key of ["x", "y", "w", "h"] as const) {
+              expect(
+                Math.abs(node!.localRect![key] - local[key]),
+                `${names.get(frame.frameId)} local ${key}`,
+              ).toBeLessThan(2);
+              expect(
+                Math.abs(node!.rect![key] - top[key]),
+                `${names.get(frame.frameId)} top ${key}`,
+              ).toBeLessThan(2);
+            }
+          }
+          expect(calls.filter((call) => call.endsWith(":Page.getLayoutMetrics"))).toHaveLength(
+            sessions.length,
+          );
+          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

@@ -1,24 +1,21 @@
-import { type CdpFrame, type CdpFrameGraph, type CdpTarget } from "@/browser-driver/frame-graph";
+import { type CdpTarget, cdpTargetKey } from "@/browser-driver/frame-graph";
 import type { RpcError } from "@/transport/types";
 import { nodeContentRegion, scrollNodeIntoView } from "./element-geometry";
 import {
   clipPolygon,
-  type GeometryProjection,
   type Point,
   type Polygon,
-  type ProjectiveEdge,
-  parseCdpQuad,
   polygonArea,
   polygonCentroid,
   projectRegionToViewport,
-  type Quad,
   type Region,
   rectPolygon,
   regionBounds,
-  type Size,
   type ViewportRect,
 } from "./geometry";
-import { type CdpRunner, cdpRunnerForTarget, isRpcError, sendToCdpTarget } from "./shared";
+import type { CssViewport } from "./geometry/coordinate-types";
+import { cssViewport, GeometryContext } from "./geometry/frame-context";
+import { type CdpRunner, cdpRunnerForTarget, isRpcError } from "./shared";
 
 export interface NodeAddress {
   target: CdpTarget;
@@ -27,6 +24,8 @@ export interface NodeAddress {
 }
 
 export interface ResolvedNodeGeometry {
+  /** The same top-level measurement used by projection, for screenshot coordinate adaptation. */
+  topViewport: CssViewport;
   topVisibleRegions: Region;
   topBounds: ViewportRect;
   /** Point in the top-level tab viewport, used by root-target input events. */
@@ -39,145 +38,16 @@ function geometryError(message: string): RpcError {
   return { code: "cdp_failed", message };
 }
 
-function frameMap(graph: CdpFrameGraph): Map<string, CdpFrame> {
-  return new Map(graph.frames.map((frame) => [frame.frameId, frame]));
-}
-
-function targetRootFrame(byId: Map<string, CdpFrame>, frame: CdpFrame): CdpFrame | null {
-  const seen = new Set<string>();
-  let current = frame;
-  while (current.parentFrameId) {
-    if (seen.has(current.frameId)) return null;
-    seen.add(current.frameId);
-    const parent = byId.get(current.parentFrameId);
-    if (!parent || parent.target.sessionId !== current.target.sessionId) break;
-    current = parent;
-  }
-  return current;
-}
-
-function frameAncestry(graph: CdpFrameGraph, frameId: string): CdpFrame[] | null {
-  const byId = frameMap(graph);
-  const path: CdpFrame[] = [];
-  const seen = new Set<string>();
-  let current = byId.get(frameId);
-  if (!current) return null;
-  while (current.parentFrameId) {
-    if (seen.has(current.frameId)) return null;
-    seen.add(current.frameId);
-    path.push(current);
-    const parent = byId.get(current.parentFrameId);
-    if (!parent) return null;
-    current = parent;
-  }
-  return path;
-}
-
-async function targetViewport(cdp: CdpRunner, target: CdpTarget): Promise<Size | null> {
-  const metrics = await sendToCdpTarget<{
-    cssLayoutViewport?: { clientWidth?: number; clientHeight?: number };
-    layoutViewport?: { clientWidth?: number; clientHeight?: number };
-  }>(cdp, target, "Page.getLayoutMetrics", {});
-  const viewport = metrics.cssLayoutViewport ?? metrics.layoutViewport ?? {};
-  const width = viewport.clientWidth ?? 0;
-  const height = viewport.clientHeight ?? 0;
-  return width > 0 && height > 0 ? { width, height } : null;
-}
-
-async function ownerContentQuad(
-  cdp: CdpRunner,
-  parent: CdpFrame,
-  ownerBackendNodeId: number,
-): Promise<Quad | null> {
-  const result = await sendToCdpTarget<{ model?: { content?: number[] } }>(
-    cdp,
-    parent.target,
-    "DOM.getBoxModel",
-    { backendNodeId: ownerBackendNodeId },
-  );
-  return parseCdpQuad(result.model?.content);
-}
-
-async function sameTargetFrameClips(
-  cdp: CdpRunner,
-  byId: Map<string, CdpFrame>,
-  frame: CdpFrame,
-  targetRoot: CdpFrame,
-): Promise<Polygon[] | null> {
-  const clips: Polygon[] = [];
-  let current = frame;
-  const seen = new Set<string>();
-  while (current.frameId !== targetRoot.frameId) {
-    if (seen.has(current.frameId) || !current.parentFrameId) return null;
-    seen.add(current.frameId);
-    const parent = byId.get(current.parentFrameId);
-    if (!parent || current.ownerBackendNodeId === undefined) return null;
-    const clip = await ownerContentQuad(cdp, parent, current.ownerBackendNodeId);
-    if (!clip) return null;
-    clips.push(clip);
-    current = parent;
-  }
-  return clips;
-}
-
-export async function resolveFrameProjection(
-  cdp: CdpRunner,
-  graph: CdpFrameGraph,
-  frameId: string,
-): Promise<GeometryProjection | null> {
-  const byId = frameMap(graph);
-  const frame = byId.get(frameId);
-  if (!frame) return null;
-  let targetRoot = targetRootFrame(byId, frame);
-  if (!targetRoot) return null;
-  const sourceViewport = await targetViewport(cdp, targetRoot.target);
-  if (!sourceViewport) return null;
-  const sourceClips = await sameTargetFrameClips(cdp, byId, frame, targetRoot);
-  if (!sourceClips) return null;
-
-  const edges: ProjectiveEdge[] = [];
-  while (targetRoot.parentFrameId) {
-    const parent = byId.get(targetRoot.parentFrameId);
-    if (!parent || targetRoot.ownerBackendNodeId === undefined) return null;
-    const destinationQuad = await ownerContentQuad(cdp, parent, targetRoot.ownerBackendNodeId);
-    if (!destinationQuad) return null;
-    const source =
-      edges.length === 0 ? sourceViewport : await targetViewport(cdp, targetRoot.target);
-    if (!source) return null;
-    const parentTargetRoot = targetRootFrame(byId, parent);
-    if (!parentTargetRoot) return null;
-    const destinationClips = await sameTargetFrameClips(cdp, byId, parent, parentTargetRoot);
-    if (!destinationClips) return null;
-    edges.push({ sourceViewport: source, destinationQuad, destinationClips });
-    targetRoot = parentTargetRoot;
-  }
-
-  const topViewport =
-    edges.length === 0 ? sourceViewport : await targetViewport(cdp, targetRoot.target);
-  return topViewport ? { sourceClips, edges, topViewport } : null;
-}
-
-async function loadFrameGraph(cdp: CdpRunner, tabId: number): Promise<CdpFrameGraph | null> {
-  if (!cdp.getFrameGraph) return null;
-  try {
-    return await cdp.getFrameGraph(tabId);
-  } catch (error) {
-    console.debug("[bsk frame-geometry] frame graph resolution failed", error);
-    return null;
-  }
-}
-
 async function scrollFrameOwners(
   cdp: CdpRunner,
   tabId: number,
-  graph: CdpFrameGraph,
+  context: GeometryContext,
   frameId: string,
 ): Promise<RpcError | null> {
-  const byId = frameMap(graph);
-  const ancestry = frameAncestry(graph, frameId);
+  const ancestry = await context.ancestry(frameId);
   if (!ancestry) return geometryError(`could not resolve frame ancestry for ${frameId}`);
   for (const child of [...ancestry].reverse()) {
-    const parent = child.parentFrameId ? byId.get(child.parentFrameId) : undefined;
+    const parent = child.parentFrameId ? await context.frame(child.parentFrameId) : undefined;
     if (!parent || child.ownerBackendNodeId === undefined) {
       return geometryError(`could not resolve frame owner for ${child.frameId}`);
     }
@@ -191,17 +61,20 @@ async function scrollFrameOwners(
   return null;
 }
 
-async function scrollElementWithFrameGraph(
+async function scrollElementWithContext(
   cdp: CdpRunner,
   tabId: number,
   target: CdpTarget,
   backendNodeId: number,
   frameId: string | undefined,
-  graph: CdpFrameGraph | null,
+  context: GeometryContext,
 ): Promise<RpcError | null> {
   if (frameId) {
-    if (!graph) return geometryError(`could not resolve frame graph for ${frameId}`);
-    const error = await scrollFrameOwners(cdp, tabId, graph, frameId);
+    const frame = await context.frame(frameId);
+    if (!frame || cdpTargetKey(frame.target) !== cdpTargetKey(target)) {
+      return geometryError("node frame does not belong to its target");
+    }
+    const error = await scrollFrameOwners(cdp, tabId, context, frameId);
     if (error) return error;
   } else if (target.sessionId) {
     return geometryError("an OOPIF node address requires frameId");
@@ -216,8 +89,15 @@ export async function scrollElementAndFramesIntoView(
   backendNodeId: number,
   frameId?: string,
 ): Promise<RpcError | null> {
-  const graph = frameId ? await loadFrameGraph(cdp, tabId) : null;
-  return scrollElementWithFrameGraph(cdp, tabId, target, backendNodeId, frameId, graph);
+  if (target.tabId !== tabId) return geometryError("node target belongs to another tab");
+  return scrollElementWithContext(
+    cdp,
+    tabId,
+    target,
+    backendNodeId,
+    frameId,
+    new GeometryContext(cdp, tabId),
+  );
 }
 
 function largestRegion(regions: Region): Polygon | null {
@@ -240,23 +120,32 @@ export async function resolveNodeGeometry(
     if (address.target.sessionId && !address.frameId) {
       return geometryError("an OOPIF node address requires frameId");
     }
-    const graph = address.frameId ? await loadFrameGraph(cdp, tabId) : null;
+    if (address.target.tabId !== tabId) return geometryError("node target belongs to another tab");
+    const context = new GeometryContext(cdp, tabId);
+    const graph = address.frameId ? await context.graph() : null;
+    if (address.frameId && graph) {
+      const frame = await context.frame(address.frameId);
+      if (!frame || cdpTargetKey(frame.target) !== cdpTargetKey(address.target)) {
+        return geometryError("node frame does not belong to its target");
+      }
+    }
     if (address.frameId && !graph) {
       return geometryError(`could not resolve frame graph for ${address.frameId}`);
     }
 
     if (options.scrollIntoView) {
-      const scrollError = await scrollElementWithFrameGraph(
+      const scrollError = await scrollElementWithContext(
         cdp,
         tabId,
         address.target,
         address.backendNodeId,
         address.frameId,
-        graph,
+        context,
       );
       if (scrollError) return scrollError;
     }
 
+    // Only topology was read above. Begin live measurements after scrolling.
     const localRegion = await nodeContentRegion(
       cdpRunnerForTarget(cdp, address.target),
       tabId,
@@ -267,7 +156,7 @@ export async function resolveNodeGeometry(
     let topVisibleRegions: Region;
     let targetActionPoint: Point | null = null;
     if (address.frameId && graph) {
-      const projection = await resolveFrameProjection(cdp, graph, address.frameId);
+      const projection = await context.targetProjection(address.frameId);
       if (!projection)
         return geometryError(`could not resolve frame geometry for ${address.frameId}`);
       topVisibleRegions = projectRegionToViewport(localRegion, projection);
@@ -290,7 +179,7 @@ export async function resolveNodeGeometry(
         targetActionPoint = localActionRegion ? polygonCentroid(localActionRegion) : null;
       }
     } else {
-      const viewport = await targetViewport(cdp, address.target);
+      const viewport = await context.viewport(address.target);
       if (!viewport) return geometryError("could not resolve top viewport geometry");
       topVisibleRegions = localRegion
         .map((polygon) =>
@@ -309,7 +198,13 @@ export async function resolveNodeGeometry(
       return { code: "permission_denied", message: "element not visible in its target" };
     }
     targetActionPoint ??= actionPoint;
-    return { topVisibleRegions, topBounds, actionPoint, targetActionPoint };
+    return {
+      topVisibleRegions,
+      topBounds,
+      actionPoint,
+      targetActionPoint,
+      topViewport: cssViewport(await context.layoutMetrics({ tabId })),
+    };
   } catch (error) {
     return geometryError(error instanceof Error ? error.message : String(error));
   }

apps/extension/src/tools/geometry.ts

@@ -245,22 +245,3 @@ export function projectRectToViewport(
   if (!rect) return null;
   return regionBounds(projectRegionToViewport([rectPolygon(rect)], projection));
 }
-
-export function childFrameProjection(
-  parent: GeometryProjection,
-  ownerRectInParent: { x: number; y: number; w: number; h: number },
-): GeometryProjection {
-  const destinationQuad = rectPolygon(ownerRectInParent);
-  return {
-    sourceClips: [],
-    edges: [
-      {
-        sourceViewport: { width: ownerRectInParent.w, height: ownerRectInParent.h },
-        destinationQuad,
-        destinationClips: parent.sourceClips,
-      },
-      ...parent.edges,
-    ],
-    topViewport: parent.topViewport,
-  };
-}

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

@@ -0,0 +1,157 @@
+import { type CdpTarget, cdpTargetKey } from "@/browser-driver/frame-graph";
+import type { GeometryProjection, ViewportRect } from "../geometry";
+import { projectRectToViewport } from "../geometry";
+
+export interface CoordinateOwner {
+  target: CdpTarget;
+  frameId?: string;
+}
+
+export interface FrameViewportRect {
+  space: "frame-viewport-css";
+  owner: CoordinateOwner;
+  rect: ViewportRect;
+}
+
+export interface SnapshotProjection {
+  source: CoordinateOwner;
+  geometry: GeometryProjection;
+}
+
+/** A failed owner read is different from a successfully projected, clipped-out rect. */
+export interface UnavailableFrameProjection {
+  status: "unavailable";
+  source: CoordinateOwner;
+  ownerBackendNodeId: number;
+}
+
+export interface UnavailableSnapshotCoordinates {
+  status: "unavailable";
+  source: CoordinateOwner;
+  reason: "snapshot-coordinates-unavailable";
+}
+
+export type SnapshotProjectionResult =
+  | { status: "available"; projection: SnapshotProjection }
+  | UnavailableFrameProjection;
+
+/** Descendants inherit the failed boundary without attempting another owner read. */
+export type FrameProjectionIssue =
+  | UnavailableFrameProjection
+  | UnavailableSnapshotCoordinates
+  | {
+      status: "blocked";
+      source: CoordinateOwner;
+      cause: UnavailableFrameProjection | UnavailableSnapshotCoordinates;
+    };
+
+export type FrameProjectionState = SnapshotProjectionResult | FrameProjectionIssue;
+
+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,
+  coordinates: SnapshotCoordinates | null,
+): FrameViewportRect | 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 (
+    !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 / scale - scroll.x,
+      y: y / scale - scroll.y,
+      width: width / scale,
+      height: height / scale,
+    },
+  };
+}
+
+export function projectSnapshotRect(
+  input: FrameViewportRect,
+  projection: SnapshotProjection,
+): ViewportRect | null {
+  if (
+    input.owner.frameId !== projection.source.frameId ||
+    cdpTargetKey(input.owner.target) !== cdpTargetKey(projection.source.target)
+  ) {
+    return null;
+  }
+  const { x, y, width: w, height: h } = input.rect;
+  return projectRectToViewport({ x, y, w, h }, projection.geometry);
+}
+
+/** CSS viewport metadata; browser zoom is distinct from raster devicePixelRatio. */
+export interface CssViewport {
+  width: number;
+  height: number;
+  scrollX: number;
+  scrollY: number;
+  cssToDip: number;
+}
+
+/** Page.captureScreenshot takes page-relative DIP, not viewport-relative CSS pixels. */
+export function screenshotPageRect(
+  rect: ViewportRect,
+  viewport: CssViewport,
+): { space: "page-dip"; rect: ViewportRect } | null {
+  const { cssToDip, scrollX, scrollY } = viewport;
+  if (
+    ![rect.x, rect.y, rect.width, rect.height, cssToDip, scrollX, scrollY].every(Number.isFinite) ||
+    cssToDip <= 0 ||
+    rect.width <= 0 ||
+    rect.height <= 0
+  )
+    return null;
+  return {
+    space: "page-dip",
+    rect: {
+      x: (rect.x + scrollX) * cssToDip,
+      y: (rect.y + scrollY) * cssToDip,
+      width: rect.width * cssToDip,
+      height: rect.height * cssToDip,
+    },
+  };
+}

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

@@ -0,0 +1,356 @@
+import {
+  type CdpFrame,
+  type CdpFrameGraph,
+  type CdpTarget,
+  cdpTargetKey,
+} from "@/browser-driver/frame-graph";
+import {
+  type GeometryProjection,
+  type Polygon,
+  type ProjectiveEdge,
+  parseCdpQuad,
+  type Quad,
+  type Size,
+} 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; clientWidth?: number; clientHeight?: number };
+  visualViewport?: { zoom?: number; clientWidth?: number; clientHeight?: number };
+  cssLayoutViewport?: {
+    clientWidth?: number;
+    clientHeight?: number;
+    pageX?: number;
+    pageY?: number;
+  };
+  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;
+  return {
+    width: value?.clientWidth ?? 0,
+    height: value?.clientHeight ?? 0,
+    scrollX: value?.pageX ?? 0,
+    scrollY: value?.pageY ?? 0,
+    cssToDip: metrics.cssVisualViewport?.zoom ?? metrics.visualViewport?.zoom ?? 1,
+  };
+}
+
+/** 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 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>;
+  private framesPromise?: Promise<Map<string, CdpFrame>>;
+
+  constructor(
+    private readonly cdp: CdpRunner,
+    private readonly tabId: number,
+    graph?: CdpFrameGraph,
+    private readonly signal?: AbortSignal,
+  ) {
+    if (graph) this.graphPromise = Promise.resolve(graph);
+  }
+
+  private async request<T>(
+    target: CdpTarget,
+    method: string,
+    params: object,
+    cleanup = false,
+  ): Promise<T> {
+    if (!cleanup && this.signal?.aborted) throw new DOMException("geometry aborted", "AbortError");
+    if (this.active >= 4) await new Promise<void>((resolve) => this.waiting.push(resolve));
+    else this.active++;
+    try {
+      if (!cleanup && this.signal?.aborted)
+        throw new DOMException("geometry aborted", "AbortError");
+      return await sendToCdpTarget<T>(this.cdp, target, method, params);
+    } finally {
+      const next = this.waiting.shift();
+      if (next) next();
+      else this.active--;
+    }
+  }
+
+  graph(): Promise<CdpFrameGraph | null> {
+    this.graphPromise ??=
+      this.cdp.getFrameGraph?.(this.tabId).catch(() => null) ?? Promise.resolve(null);
+    return this.graphPromise;
+  }
+
+  private frames(): Promise<Map<string, CdpFrame>> {
+    this.framesPromise ??= this.graph().then(
+      (graph) => new Map(graph?.frames.map((frame) => [frame.frameId, frame]) ?? []),
+    );
+    return this.framesPromise;
+  }
+
+  async frame(frameId: string): Promise<CdpFrame | undefined> {
+    return (await this.frames()).get(frameId);
+  }
+
+  /** Topology only: safe to resolve before the caller scrolls frame owners. */
+  async ancestry(frameId: string): Promise<CdpFrame[] | null> {
+    const frames = await this.frames();
+    const path: CdpFrame[] = [];
+    const seen = new Set<string>();
+    let current = frames.get(frameId);
+    if (!current) return null;
+    while (current.parentFrameId) {
+      if (seen.has(current.frameId)) return null;
+      seen.add(current.frameId);
+      path.push(current);
+      const parent = frames.get(current.parentFrameId);
+      if (!parent) return null;
+      current = parent;
+    }
+    return path;
+  }
+
+  layoutMetrics(target: CdpTarget): Promise<LayoutMetrics> {
+    const key = cdpTargetKey(target);
+    let promise = this.metrics.get(key);
+    if (!promise) {
+      promise = this.request<LayoutMetrics>(target, "Page.getLayoutMetrics", {});
+      this.metrics.set(key, promise);
+    }
+    return promise;
+  }
+
+  async viewport(target: CdpTarget): Promise<Size | null> {
+    const { width, height } = cssViewport(await this.layoutMetrics(target));
+    return Number.isFinite(width) && Number.isFinite(height) && width > 0 && height > 0
+      ? { width, height }
+      : null;
+  }
+
+  ownerContent(target: CdpTarget, backendNodeId: number): Promise<Quad | null> {
+    const key = `${cdpTargetKey(target)}:${backendNodeId}`;
+    let promise = this.owners.get(key);
+    if (!promise) {
+      promise = this.request<{ model?: { content?: number[] } }>(target, "DOM.getBoxModel", {
+        backendNodeId,
+      }).then((reply) => parseCdpQuad(reply.model?.content));
+      this.owners.set(key, promise);
+    }
+    return promise;
+  }
+
+  /** Same-target owner quads are already target-relative, including nested owners. */
+  async snapshotProjection(
+    source: CoordinateOwner,
+    ownerBackendNodeId: number,
+    ancestorClips: Polygon[],
+    viewport: Size,
+  ): Promise<SnapshotProjectionResult> {
+    const key = `${cdpTargetKey(source.target)}:${ownerBackendNodeId}`;
+    let promise = this.snapshotOwners.get(key);
+    if (!promise) {
+      promise = this.snapshotOwner(source.target, ownerBackendNodeId);
+      this.snapshotOwners.set(key, promise);
+    }
+    let owner: { quad: Quad; size: Size } | null;
+    try {
+      owner = await promise;
+    } catch (error) {
+      if (error && typeof error === "object" && "name" in error && error.name === "AbortError")
+        throw error;
+      console.debug("[bsk geometry] frame owner unavailable", error);
+      owner = null;
+    }
+    return owner
+      ? {
+          status: "available",
+          projection: {
+            source,
+            geometry: {
+              sourceClips: [],
+              edges: [
+                {
+                  sourceViewport: owner.size,
+                  destinationQuad: owner.quad,
+                  destinationClips: ancestorClips,
+                },
+              ],
+              topViewport: viewport,
+            },
+          },
+        }
+      : { 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",
+      { backendNodeId },
+    );
+    const objectId = resolved.object?.objectId;
+    if (!objectId) return null;
+    try {
+      const reply = await this.request<{ result?: { value?: Size }; exceptionDetails?: unknown }>(
+        target,
+        "Runtime.callFunctionOn",
+        {
+          objectId,
+          functionDeclaration: `function() {
+          if (!this.isConnected) return null;
+          const style = getComputedStyle(this);
+          return {
+            width: this.clientWidth - parseFloat(style.paddingLeft) - parseFloat(style.paddingRight),
+            height: this.clientHeight - parseFloat(style.paddingTop) - parseFloat(style.paddingBottom)
+          };
+        }`,
+          returnByValue: true,
+        },
+      );
+      const size = reply.result?.value;
+      return !reply.exceptionDetails &&
+        size &&
+        Number.isFinite(size.width) &&
+        Number.isFinite(size.height) &&
+        size.width > 0 &&
+        size.height > 0
+        ? { quad, size }
+        : null;
+    } finally {
+      // Cleanup must still run if cancellation arrived after resolving the object.
+      await this.request(target, "Runtime.releaseObject", { objectId }, true).catch(() => {});
+    }
+  }
+
+  private targetRoot(frames: Map<string, CdpFrame>, frame: CdpFrame): CdpFrame | null {
+    const seen = new Set<string>();
+    let current = frame;
+    while (current.parentFrameId) {
+      if (seen.has(current.frameId)) return null;
+      seen.add(current.frameId);
+      const parent = frames.get(current.parentFrameId);
+      if (!parent) return null;
+      if (cdpTargetKey(parent.target) !== cdpTargetKey(current.target)) break;
+      current = parent;
+    }
+    return current;
+  }
+
+  private async clips(
+    frames: Map<string, CdpFrame>,
+    frame: CdpFrame,
+    root: CdpFrame,
+  ): Promise<Polygon[] | null> {
+    const clips: Polygon[] = [];
+    let current = frame;
+    const seen = new Set<string>();
+    while (current.frameId !== root.frameId) {
+      if (seen.has(current.frameId) || !current.parentFrameId) return null;
+      seen.add(current.frameId);
+      const parent = frames.get(current.parentFrameId);
+      if (!parent || current.ownerBackendNodeId === undefined) return null;
+      const quad = await this.ownerContent(parent.target, current.ownerBackendNodeId);
+      if (!quad) return null;
+      clips.push(quad);
+      current = parent;
+    }
+    return clips;
+  }
+
+  /** Input is already in the frame's CDP target viewport, not its local viewport. */
+  targetProjection(frameId: string): Promise<GeometryProjection | null> {
+    let promise = this.projections.get(frameId);
+    if (!promise) {
+      promise = this.buildTargetProjection(frameId);
+      this.projections.set(frameId, promise);
+    }
+    return promise;
+  }
+
+  private async buildTargetProjection(frameId: string): Promise<GeometryProjection | null> {
+    const frames = await this.frames();
+    const frame = frames.get(frameId);
+    if (!frame) return null;
+    let root = this.targetRoot(frames, frame);
+    if (!root) return null;
+    const sourceViewport = await this.viewport(root.target);
+    if (!sourceViewport) return null;
+    const sourceClips = await this.clips(frames, frame, root);
+    if (!sourceClips) return null;
+    const edges: ProjectiveEdge[] = [];
+    const seen = new Set<string>();
+    while (root.parentFrameId) {
+      if (seen.has(root.frameId)) return null;
+      seen.add(root.frameId);
+      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);
+      const parentRoot = this.targetRoot(frames, parent);
+      if (!destinationQuad || !source || !parentRoot) return null;
+      const destinationClips = await this.clips(frames, parent, parentRoot);
+      if (!destinationClips) return null;
+      edges.push({ sourceViewport: source, destinationQuad, destinationClips });
+      root = parentRoot;
+    }
+    const topViewport = await this.viewport(root.target);
+    return topViewport ? { sourceClips, edges, topViewport } : null;
+  }
+}

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

@@ -34,6 +34,8 @@ import type {
 import { attachDialogs, markDialogCursor } from "./dialogs";
 import { rpcError } from "./errors";
 import { resolveNodeGeometry } from "./frame-geometry";
+import { screenshotPageRect } from "./geometry/coordinate-types";
+import { cssViewport, GeometryContext } from "./geometry/frame-context";
 import {
   type ChromeTabsApi,
   enforceToolTargetScope,
@@ -197,15 +199,14 @@ async function captureElementScreenshot(
   if (isRpcError(geometry)) return geometry;
   if (signal?.aborted) return cancelled("screenshot");
   const rect = geometry.topBounds;
+  const clip = screenshotPageRect(rect, geometry.topViewport);
+  if (!clip) return { code: "cdp_failed", message: "invalid screenshot coordinate space" };
 
   try {
     const shot = await cdp.send<{ data?: string }>(tabId, "Page.captureScreenshot", {
       format: "png",
       clip: {
-        x: rect.x,
-        y: rect.y,
-        width: rect.width,
-        height: rect.height,
+        ...clip.rect,
         scale: 1,
       },
     });
@@ -984,26 +985,19 @@ function emptyCapturedViewModel(viewport = { width: 0, height: 0 }): CapturedVie
   return { viewport, nodes: [], iframeNodes: new Map(), excludedBackendNodeIds: new Set() };
 }
 
-interface LayoutMetricsViewportReply {
-  cssLayoutViewport?: { clientWidth?: number; clientHeight?: number };
-  layoutViewport?: { clientWidth?: number; clientHeight?: number };
-}
-
 async function fallbackCapturedViewModel(
   cdp: CdpRunner,
   tabId: number,
+  geometry: GeometryContext,
   signal?: AbortSignal,
 ): Promise<CapturedViewModel> {
   throwIfAborted(signal, "observation");
   let viewport = { width: 0, height: 0 };
   try {
-    const metrics = await cdp.send<LayoutMetricsViewportReply>(tabId, "Page.getLayoutMetrics", {});
+    const metrics = await geometry.layoutMetrics({ tabId });
     throwIfAborted(signal, "observation");
-    const source = metrics.cssLayoutViewport ?? metrics.layoutViewport ?? {};
-    viewport = {
-      width: source.clientWidth ?? 0,
-      height: source.clientHeight ?? 0,
-    };
+    const source = cssViewport(metrics);
+    viewport = { width: source.width, height: source.height };
   } catch (error) {
     if (isAbortError(error)) throw error;
   }
@@ -1016,12 +1010,13 @@ async function captureForVom(
   cdp: CdpRunner,
   tabId: number,
   options: CaptureVomObservationOptions,
+  geometry: GeometryContext,
 ): Promise<CapturedViewModel> {
   try {
-    return await captureViewModel(cdp, tabId, { signal: options.signal });
+    return await captureViewModel(cdp, tabId, { signal: options.signal, geometry });
   } catch (error) {
     if (isAbortError(error)) throw error;
-    return fallbackCapturedViewModel(cdp, tabId, options.signal);
+    return fallbackCapturedViewModel(cdp, tabId, geometry, options.signal);
   }
 }
 
@@ -1096,9 +1091,16 @@ export async function captureVomObservation(
   throwIfAborted(options.signal, "observation");
   await cdp.ensureAttachedToUrl?.(tabId, url);
   throwIfAborted(options.signal, "observation");
-  const captured = await captureForVom(cdp, tabId, options);
+  const geometry = new GeometryContext(cdp, tabId, undefined, options.signal);
+  const captured = await captureForVom(cdp, tabId, options, geometry);
   throwIfAborted(options.signal, "observation");
-  const documents = await captureFrameData<CdpAxNode>(cdp, tabId, captured, options.signal);
+  const documents = await captureFrameData<CdpAxNode>(
+    cdp,
+    tabId,
+    captured,
+    options.signal,
+    geometry,
+  );
   throwIfAborted(options.signal, "observation");
   const normalizedDocuments =
     documents.length === 1 && captured.iframeNodes.size > 0
@@ -1131,12 +1133,21 @@ export async function captureVomObservation(
     captured,
     hoverProbes.surfaceProbes,
   );
+  // 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 = captured.frameGeometryIssues?.length
+    ? "@warning geometry incomplete: some page or frame content has no top-level coordinates.\n"
+    : "";
   const rendered = renderVom(decoratedScene, {
     maxDepth: options.maxDepth,
-    maxTokens: options.maxTokens,
+    maxTokens:
+      !geometryNotice || options.maxTokens === undefined
+        ? options.maxTokens
+        : Math.max(0, options.maxTokens - Math.ceil(geometryNotice.length / 4)),
     redactValues: options.redactValues,
     activeRegionPolicy: options.activeRegionPolicy,
   });
+  if (geometryNotice) rendered.text += `\n${geometryNotice.trimEnd()}`;
   throwIfAborted(options.signal, "observation");
   return projectRecordSafeObservation({
     rootFrameId: captured.rootFrameId ?? normalizedDocuments[0]?.frameId ?? "root",

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

@@ -1,5 +1,6 @@
 import { describe, expect, it, vi } from "vitest";
 import { OVERLAY_HOST_MARKER_ATTR, OVERLAY_HOST_NAME } from "../../../lib/overlay-bridge";
+import type { CdpRunner } from "../../shared";
 import { captureViewModel, collectOverlayExcludedBackendIds, probeHoverSurfaces } from "../capture";
 
 // Minimal but format-accurate captureSnapshot reply: a body with one
@@ -210,7 +211,11 @@ 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 {
@@ -298,6 +303,8 @@ describe("captureViewModel", () => {
         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 },
           };
         }
@@ -361,6 +368,8 @@ describe("captureViewModel", () => {
         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 },
           };
         }
@@ -409,6 +418,8 @@ describe("captureViewModel", () => {
         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 },
           };
         }
@@ -742,6 +753,8 @@ describe("captureViewModel", () => {
         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 },
           };
         }
@@ -754,7 +767,46 @@ describe("captureViewModel", () => {
     expect(div?.rect).toMatchObject({ y: 0, h: 600 });
   });
 
-  it("normalizes device-pixel bounds by devicePixelRatio", async () => {
+  it("normalizes snapshot-owned scroll before using a stale CSS metrics fallback", async () => {
+    const snapshot = {
+      strings: ["html", "button"],
+      documents: [
+        {
+          frameId: "root",
+          scrollOffsetX: 40,
+          scrollOffsetY: 200,
+          nodes: {
+            parentIndex: [-1, 0],
+            nodeName: [0, 1],
+            backendNodeId: [10, 11],
+            attributes: [[], []],
+          },
+          layout: { nodeIndex: [1], bounds: [[200, 800, 240, 80]] },
+        },
+      ],
+    };
+    const cdp: CdpRunner = {
+      send: vi.fn(async (_tab: number, method: string) => {
+        if (method === "DOMSnapshot.captureSnapshot") return snapshot;
+        if (method === "Page.getLayoutMetrics")
+          return {
+            visualViewport: { clientWidth: 2000 },
+            cssVisualViewport: { clientWidth: 1000 },
+            cssLayoutViewport: { clientWidth: 1000, clientHeight: 800, pageX: 999, pageY: 999 },
+          };
+        return {};
+      }) as CdpRunner["send"],
+    };
+    const captured = await captureViewModel(cdp, 4);
+    expect(captured.nodes.find((node) => node.backendNodeId === 11)).toMatchObject({
+      localRect: { x: 80, y: 300, w: 120, h: 40 },
+      rect: { x: 80, y: 300, w: 120, h: 40 },
+      rendered: true,
+    });
+    expect(captured.frameGeometryIssues).toEqual([]);
+  });
+
+  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 = {
@@ -788,6 +840,8 @@ describe("captureViewModel", () => {
         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 },
           };
@@ -802,6 +856,12 @@ describe("captureViewModel", () => {
       w: 1000,
       h: 800,
     });
+    expect(nodes.find((n) => n.backendNodeId === 12)?.localRect).toEqual({
+      x: 0,
+      y: 0,
+      w: 1000,
+      h: 800,
+    });
   });
 
   it("extracts textContent from #text child nodes via nodeValue", async () => {
@@ -857,6 +917,8 @@ describe("captureViewModel", () => {
         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 },
           };
         }
@@ -947,9 +1009,17 @@ describe("captureViewModel", () => {
         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 },
           };
         }
+        if (method === "DOM.getBoxModel")
+          return { model: { content: [100, 300, 900, 300, 900, 700, 100, 700] } };
+        if (method === "DOM.resolveNode") return { object: { objectId: "owner" } };
+        if (method === "Runtime.callFunctionOn")
+          return { result: { value: { width: 800, height: 400 } } };
+        if (method === "Runtime.releaseObject") return {};
         throw new Error(method);
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
@@ -979,7 +1049,7 @@ describe("captureViewModel", () => {
     expect(frameParentIds?.get("child-frame")).toBe("main-frame");
   });
 
-  it("captures iframe documents without requiring owner-frame geometry", async () => {
+  it("projects iframe documents independently of owner snapshot geometry", async () => {
     const S = [
       "html",
       "body",
@@ -1037,9 +1107,17 @@ describe("captureViewModel", () => {
         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 },
           };
         }
+        if (method === "DOM.getBoxModel")
+          return { model: { content: [100, 300, 900, 300, 900, 700, 100, 700] } };
+        if (method === "DOM.resolveNode") return { object: { objectId: "owner" } };
+        if (method === "Runtime.callFunctionOn")
+          return { result: { value: { width: 800, height: 400 } } };
+        if (method === "Runtime.releaseObject") return {};
         throw new Error(method);
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
@@ -1048,7 +1126,7 @@ describe("captureViewModel", () => {
     const input = iframeNodes.get(13)?.find((n) => n.backendNodeId === 101);
 
     expect(input?.localRect).toEqual({ x: 20, y: 20, w: 120, h: 60 });
-    expect(input?.rect).toBeNull();
+    expect(input?.rect).toEqual({ x: 120, y: 320, w: 120, h: 60 });
   });
 
   it("recursively normalizes nested iframe sub-documents", async () => {
@@ -1097,6 +1175,8 @@ describe("captureViewModel", () => {
             attributes: [[], [], []],
             contentDocumentIndex: { index: [2], value: [2] },
           },
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           layout: {
             nodeIndex: [1, 2],
             styles: [
@@ -1117,6 +1197,8 @@ describe("captureViewModel", () => {
             backendNodeId: [30, 31],
             attributes: [[], [i("type"), i("text")]],
           },
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
           layout: {
             nodeIndex: [1],
             styles: [[i("static"), i("auto")]],
@@ -1127,16 +1209,45 @@ describe("captureViewModel", () => {
       ],
     };
     const cdp = {
-      send: vi.fn(async (_t: number, method: string) => {
-        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 },
-          };
-        }
-        throw new Error(method);
-      }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
+      send: vi.fn(
+        async (
+          _t: number,
+          method: string,
+          params?: { backendNodeId?: number; objectId?: string },
+        ) => {
+          if (method === "DOMSnapshot.enable") return {};
+          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 },
+            };
+          }
+          if (method === "DOM.getBoxModel")
+            return {
+              model: {
+                content:
+                  params?.backendNodeId === 13
+                    ? [10, 20, 310, 20, 310, 220, 10, 220]
+                    : [15, 26, 115, 26, 115, 106, 15, 106],
+              },
+            };
+          if (method === "DOM.resolveNode")
+            return { object: { objectId: String(params?.backendNodeId) } };
+          if (method === "Runtime.callFunctionOn")
+            return {
+              result: {
+                value:
+                  params?.objectId === "13"
+                    ? { width: 300, height: 200 }
+                    : { width: 100, height: 80 },
+              },
+            };
+          if (method === "Runtime.releaseObject") return {};
+          throw new Error(method);
+        },
+      ) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
 
     const { iframeNodes } = await captureViewModel(cdp, 4);
@@ -1150,7 +1261,7 @@ describe("captureViewModel", () => {
     expect(input?.rect).toEqual({ x: 16, y: 28, w: 40, h: 20 });
   });
 
-  it("normalizes bounds then subtracts CSS scroll at dpr>1", async () => {
+  it("subtracts CSS scroll once without dividing snapshot bounds by a metrics ratio", async () => {
     const S = ["html", "body", "div", "position", "fixed", "static", "pointer-events", "auto"];
     const i = (s: string) => S.indexOf(s);
     const snapshot = {
@@ -1184,6 +1295,8 @@ describe("captureViewModel", () => {
         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 },
           };
@@ -1217,3 +1330,200 @@ describe("captureViewModel", () => {
     expect(excluded).toEqual(new Set([200, 201, 202]));
   });
 });
+
+// Six sibling frames and one nested frame exercise scheduling through the real capture entry.
+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)],
+      nodeName: [0, ...owners.map(() => 1)],
+      backendNodeId: [1000 + id, ...owners],
+      attributes: [[], ...owners.map(() => [])],
+      contentDocumentIndex: { index: owners.map((_, i) => i + 1), value: childIndexes },
+    },
+    layout: {
+      nodeIndex: [0, ...owners.map((_, i) => i + 1)],
+      bounds: [[0, 0, 200, 100], ...owners.map(() => [0, 0, 200, 100])],
+    },
+  });
+  const snapshot = {
+    strings: ["body", "iframe"],
+    documents: [
+      document(0, [100, 101, 102, 103, 104, 105], [1, 2, 3, 4, 5, 6]),
+      document(1, [200], [7]),
+      ...Array.from({ length: 6 }, (_, i) => document(i + 2, [], [])),
+    ],
+  };
+  let active = 0;
+  let peak = 0;
+  const send = vi.fn(async (_tabId: number, method: string, params: object = {}) => {
+    const args = params as Record<string, unknown>;
+    active++;
+    peak = Math.max(peak, active);
+    try {
+      await beforeReply(method, args);
+      if (method === "DOMSnapshot.captureSnapshot") return snapshot;
+      if (method === "Page.getLayoutMetrics")
+        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) } };
+      if (method === "Runtime.callFunctionOn")
+        return { result: { value: { width: 200, height: 100 } } };
+      return {};
+    } finally {
+      active--;
+    }
+  });
+  return {
+    cdp: { send: send as CdpRunner["send"] },
+    send,
+    peak: () => peak,
+    active: () => active,
+    measured: () =>
+      send.mock.calls
+        .filter(([, method]) => method === "DOM.getBoxModel")
+        .map(([, , params]) => (params as { backendNodeId: number }).backendNodeId),
+  };
+}
+
+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 captureViewModel(fixture.cdp, 4);
+    expect(captured.frameGeometryIssues).toEqual([]);
+    expect([...captured.iframeNodes.keys()]).toEqual([100, 200, 101, 102, 103, 104, 105]);
+    expect(captured.iframeNodes.get(200)?.[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 depth-first output despite reordered replies", async () => {
+    const pending = new Map<number, () => void>();
+    const fixture = siblingCaptureFixture(async (method, params) => {
+      if (method === "DOM.getBoxModel" && Number(params.backendNodeId) < 200)
+        await new Promise<void>((resolve) => pending.set(Number(params.backendNodeId), resolve));
+    });
+    const capture = captureViewModel(fixture.cdp, 4);
+    await vi.waitFor(() => expect(pending.size).toBe(4));
+    expect(fixture.measured()).toEqual([100, 101, 102, 103]);
+    pending.get(103)!();
+    await vi.waitFor(() => expect(pending.has(104)).toBe(true));
+    pending.get(104)!();
+    await vi.waitFor(() => expect(pending.has(105)).toBe(true));
+    expect(fixture.measured()).not.toContain(200);
+    for (const id of [105, 102, 101, 100]) pending.get(id)!();
+    const captured = await capture;
+    expect(captured.frameGeometryIssues).toEqual([]);
+    expect(fixture.peak()).toBe(4);
+    expect(fixture.active()).toBe(0);
+    expect(fixture.measured()).toEqual([100, 101, 102, 103, 104, 105, 200]);
+    expect([...captured.iframeNodes.keys()]).toEqual([100, 200, 101, 102, 103, 104, 105]);
+    expect(captured.iframeNodes.get(200)?.[0].rect).toEqual({ x: 0, y: 0, w: 200, h: 100 });
+    for (const method of [
+      "DOM.getBoxModel",
+      "DOM.resolveNode",
+      "Runtime.callFunctionOn",
+      "Runtime.releaseObject",
+    ])
+      expect(fixture.send.mock.calls.filter(([, name]) => name === method)).toHaveLength(7);
+  });
+
+  it("does not measure descendants of a failed owner and retains sibling geometry and local nodes", async () => {
+    const fixture = siblingCaptureFixture(async (method, params) => {
+      if (method === "DOM.resolveNode" && params.backendNodeId === 100)
+        throw new Error("owner replaced");
+    });
+    const captured = await captureViewModel(fixture.cdp, 4);
+    expect(captured.frameGeometryIssues).toEqual([
+      {
+        status: "unavailable",
+        source: { target: { tabId: 4 }, frameId: "frame-1" },
+        ownerBackendNodeId: 100,
+      },
+      {
+        status: "blocked",
+        source: { target: { tabId: 4 }, frameId: "frame-7" },
+        cause: captured.frameGeometryIssues?.[0],
+      },
+    ]);
+    expect(fixture.measured()).not.toContain(200);
+    expect(captured.iframeNodes.get(200)?.[0]).toMatchObject({
+      tag: "body",
+      rect: null,
+      localRect: { x: 0, y: 0, w: 200, h: 100 },
+    });
+    expect(captured.iframeNodes.get(101)?.[0].rect).toEqual({ x: 0, y: 0, w: 200, h: 100 });
+    expect([...captured.iframeNodes.keys()]).toEqual([100, 200, 101, 102, 103, 104, 105]);
+  });
+
+  it("stops scheduling on cancellation and waits for resolved objects to be released", async () => {
+    const controller = new AbortController();
+    const resolutions = new Map<string, () => void>();
+    const releases = new Map<string, () => void>();
+    const fixture = siblingCaptureFixture(async (method, params) => {
+      if (method === "DOM.resolveNode")
+        await new Promise<void>((resolve) =>
+          resolutions.set(String(params.backendNodeId), resolve),
+        );
+      if (method === "Runtime.releaseObject")
+        await new Promise<void>((resolve) => releases.set(String(params.objectId), resolve));
+    });
+    let settled = false;
+    const capture = captureViewModel(fixture.cdp, 4, { signal: controller.signal });
+    const rejected = expect(capture).rejects.toMatchObject({ name: "AbortError" });
+    void capture.then(
+      () => {
+        settled = true;
+      },
+      () => {
+        settled = true;
+      },
+    );
+    await vi.waitFor(() => expect(resolutions.size).toBe(4));
+    controller.abort();
+    for (const resolve of resolutions.values()) resolve();
+    await vi.waitFor(() => expect(releases.size).toBe(4));
+    expect(settled).toBe(false);
+    expect(fixture.measured()).toEqual([100, 101, 102, 103]);
+    for (const release of releases.values()) release();
+    await rejected;
+    expect(fixture.active()).toBe(0);
+    expect(fixture.send.mock.calls.some(([, method]) => method === "Runtime.callFunctionOn")).toBe(
+      false,
+    );
+  });
+});

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

@@ -25,6 +25,8 @@ function childSnapshot(frameId: string, backendNodeId: number) {
     strings,
     documents: [
       {
+        scrollOffsetX: 0,
+        scrollOffsetY: 0,
         frameId,
         nodes: {
           parentIndex: [-1, 0],
@@ -50,6 +52,72 @@ function childSnapshot(frameId: string, backendNodeId: number) {
 }
 
 describe("captureFrameData", () => {
+  it("retains nested owner failures when merging a captured OOPIF", async () => {
+    const owner = ownerNode(10, 50);
+    const captured: CapturedViewModel = {
+      nodes: [owner],
+      viewport: { width: 1000, height: 800 },
+      iframeNodes: new Map(),
+      frameNodes: new Map([["main", [owner]]]),
+      rootFrameId: "main",
+      excludedBackendNodeIds: new Set(),
+    };
+    const child = childSnapshot("child", 101);
+    const nested = childSnapshot("nested", 201);
+    const document = child.documents[0];
+    const snapshot = {
+      strings: child.strings,
+      documents: [
+        {
+          ...document,
+          nodes: { ...document.nodes, contentDocumentIndex: { index: [1], value: [1] } },
+        },
+        nested.documents[0],
+      ],
+    };
+    const reply = async (_target: unknown, method: string) => {
+      if (method === "Page.getLayoutMetrics")
+        return {
+          visualViewport: { clientWidth: 1000 },
+          cssVisualViewport: { clientWidth: 1000 },
+          cssLayoutViewport: { clientWidth: 300, clientHeight: 200 },
+        };
+      if (method === "DOMSnapshot.captureSnapshot") return snapshot;
+      if (method === "DOM.getBoxModel")
+        return { model: { content: [50, 100, 350, 100, 350, 300, 50, 300] } };
+      if (method === "DOM.resolveNode") throw new Error("nested owner replaced");
+      return {};
+    };
+    const cdp: CdpRunner = {
+      send: vi.fn(reply) as CdpRunner["send"],
+      sendToTarget: vi.fn(reply) as NonNullable<CdpRunner["sendToTarget"]>,
+      getFrameGraph: vi.fn(async () => ({
+        rootFrameId: "main",
+        frames: [
+          { frameId: "main", target: { tabId: 4 } },
+          {
+            frameId: "child",
+            parentFrameId: "main",
+            ownerBackendNodeId: 10,
+            target: { tabId: 4, sessionId: "child-session" },
+          },
+        ],
+      })),
+    };
+    await captureFrameData(cdp, 4, captured);
+    expect(captured.frameGeometryIssues).toEqual([
+      {
+        status: "unavailable",
+        source: { target: { tabId: 4, sessionId: "child-session" }, frameId: "nested" },
+        ownerBackendNodeId: 101,
+      },
+    ]);
+    expect(captured.frameNodes?.get("nested")?.[1]).toMatchObject({
+      rect: null,
+      localRect: { x: 10, y: 20, w: 100, h: 40 },
+    });
+  });
+
   it("captures and positions multiple OOPIF documents missing from the root snapshot", async () => {
     const leftOwner = ownerNode(10, 50);
     const rightOwner = ownerNode(20, 500);
@@ -64,7 +132,11 @@ describe("captureFrameData", () => {
     };
     const sendToTarget = vi.fn(async (target, method) => {
       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") {
@@ -85,7 +157,11 @@ describe("captureFrameData", () => {
           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"],
@@ -149,7 +225,11 @@ describe("captureFrameData", () => {
         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"],
@@ -192,7 +272,12 @@ describe("captureFrameData", () => {
       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 }),
     );
+    expect(captured.frameGeometryIssues).toContainEqual({
+      status: "unavailable",
+      source: { target: { tabId: 4, sessionId: "child-session" }, frameId: "child" },
+      reason: "snapshot-coordinates-unavailable",
+    });
   });
 });

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

@@ -5,9 +5,22 @@
 // STYLE_COL so capture and visibility policy share one explicit contract.
 
 import type { Rect, Viewport } from "@browser-skill/vom";
+import type { CdpTarget } from "@/browser-driver/frame-graph";
 import { evaluateHoverTrigger } from "@/lib/hover-trigger-policy";
 import { isOverlayHostNode, OVERLAY_HOST_SELECTOR } from "../../lib/overlay-bridge";
-import { childFrameProjection, type GeometryProjection, projectRectToViewport } from "../geometry";
+import {
+  type FrameProjectionIssue,
+  type FrameProjectionState,
+  projectSnapshotRect,
+  type SnapshotCoordinates,
+  snapshotCoordinates,
+  snapshotViewportRect,
+} from "../geometry/coordinate-types";
+import {
+  GeometryContext,
+  type LayoutMetrics,
+  snapshotLayoutScale,
+} from "../geometry/frame-context";
 import type { CdpRunner } from "../shared";
 import { clearHover, ProbeBudget, waitForHover } from "./hover-perception";
 
@@ -71,12 +84,16 @@ export interface CapturedViewModel {
   /** Explicit DOMSnapshot frame ancestry; never inferred from backend node ids. */
   frameParentIds?: Map<string, string>;
   rootFrameId?: string;
+  /** Failed boundaries and descendants blocked by them; clipping is not a failure. */
+  frameGeometryIssues?: FrameProjectionIssue[];
   /** Backend node ids belonging to the agent overlay host + its shadow subtree. */
   excludedBackendNodeIds: Set<number>;
 }
 
 export interface CaptureViewModelOptions {
   signal?: AbortSignal;
+  geometry?: GeometryContext;
+  target?: CdpTarget;
 }
 
 function captureAbortError(): Error {
@@ -147,16 +164,6 @@ interface SnapshotReply {
   documents?: SnapshotDocument[];
 }
 
-interface LayoutMetricsReply {
-  cssLayoutViewport?: {
-    clientWidth?: number;
-    clientHeight?: number;
-    pageX?: number;
-    pageY?: number;
-  };
-  layoutViewport?: { clientWidth?: number; clientHeight?: number; pageX?: number; pageY?: number };
-}
-
 function isFormControlTag(tag: string): boolean {
   return tag === "input" || tag === "textarea" || tag === "select";
 }
@@ -353,9 +360,10 @@ interface ParseDocumentResult {
 interface FrameContext {
   frameId?: string;
   ownerFrameBackendNodeId: number | null;
-  projection: GeometryProjection | null;
-  scrollX: number;
-  scrollY: number;
+  projection: FrameProjectionState;
+  target: CdpTarget;
+  coordinates: SnapshotCoordinates | null;
+  layoutUnitsPerCssPixel: number | null;
 }
 
 function str(strings: string[], idx: number | undefined): string {
@@ -363,15 +371,6 @@ function str(strings: string[], idx: number | undefined): string {
   return strings[idx] ?? "";
 }
 
-function devicePixelRatio(metrics: LayoutMetricsReply): number {
-  const layoutW = metrics.layoutViewport?.clientWidth ?? 0;
-  const cssW = metrics.cssLayoutViewport?.clientWidth ?? 0;
-  if (!layoutW || !cssW) return 1;
-  const dpr = layoutW / cssW;
-  if (!Number.isFinite(dpr) || dpr <= 0) return 1;
-  return dpr >= 1 ? dpr : 1;
-}
-
 function sparseIndexMap(sparse: SparseArray | undefined): Map<number, number> {
   const out = new Map<number, number>();
   if (!sparse?.index || !sparse.value) return out;
@@ -797,13 +796,11 @@ export async function collectOverlayExcludedBackendIds(
  *
  * @param doc   - the raw DOMSnapshot document object
  * @param strings - the shared string table for the whole snapshot
- * @param dpr   - device-pixel-ratio from Page.getLayoutMetrics
  * @param context - frame coordinate context; output rects are top viewport-relative
  */
 function parseDocumentNodes(
   doc: SnapshotDocument,
   strings: string[],
-  dpr: number,
   context: FrameContext,
 ): ParseDocumentResult {
   const dn = doc.nodes;
@@ -898,15 +895,19 @@ function parseDocumentNodes(
     if (li !== undefined) {
       const b = dl?.bounds?.[li];
       if (b && b.length >= 4 && b[2] > 0 && b[3] > 0) {
-        localRect = {
-          x: b[0] / dpr - context.scrollX,
-          y: b[1] / dpr - context.scrollY,
-          w: b[2] / dpr,
-          h: b[3] / dpr,
-        };
-        const bounds = context.projection
-          ? projectRectToViewport(localRect, context.projection)
-          : null;
+        const input = snapshotViewportRect(
+          b,
+          { target: context.target, frameId: context.frameId },
+          context.coordinates,
+        );
+        if (input) {
+          const { x, y, width: w, height: h } = input.rect;
+          localRect = { x, y, w, h };
+        }
+        const bounds =
+          input && context.projection.status === "available"
+            ? projectSnapshotRect(input, context.projection.projection)
+            : null;
         rect = bounds ? { x: bounds.x, y: bounds.y, w: bounds.width, h: bounds.height } : null;
       }
       paintOrder = dl?.paintOrders?.[li] ?? 0;
@@ -917,7 +918,11 @@ function parseDocumentNodes(
       const visibility = str(strings, styleRow[visibilityCol]) || "visible";
       const opacity = str(strings, styleRow[opacityCol]) || "1";
       rendered =
-        localRect !== null &&
+        !!b &&
+        b.length >= 4 &&
+        b.slice(0, 4).every(Number.isFinite) &&
+        b[2] > 0 &&
+        b[3] > 0 &&
         visibility !== "hidden" &&
         visibility !== "collapse" &&
         (Number.parseFloat(opacity) || 0) > 0;
@@ -974,21 +979,23 @@ function parseDocumentNodes(
 }
 
 interface ParseFrameDocumentsResult {
+  frameGeometryIssues: FrameProjectionIssue[];
   iframeNodes: CapturedIframeNodes;
   frameOwnerBackendNodeIds: Map<string, number>;
   frameParentIds: Map<string, string>;
   excludedBackendNodeIds: Set<number>;
 }
 
-function parseChildFrameDocuments(
+async function parseChildFrameDocuments(
   documents: SnapshotDocument[],
   strings: string[],
-  dpr: number,
   parentDocIndex: number,
-  parentNodes: CapturedNode[],
   parentContext: FrameContext,
+  geometry: GeometryContext,
+  signal?: AbortSignal,
   visited = new Set<number>(),
-): ParseFrameDocumentsResult {
+): Promise<ParseFrameDocumentsResult> {
+  const frameGeometryIssues: FrameProjectionIssue[] = [];
   const iframeNodes: CapturedIframeNodes = new Map();
   const frameOwnerBackendNodeIds = new Map<string, number>();
   const frameParentIds = new Map<string, string>();
@@ -996,34 +1003,100 @@ function parseChildFrameDocuments(
   const parentDoc = documents[parentDocIndex];
   const cdi = sparseIndexMap(parentDoc?.nodes?.contentDocumentIndex);
   if (cdi.size === 0) {
-    return { iframeNodes, frameOwnerBackendNodeIds, frameParentIds, excludedBackendNodeIds };
+    return {
+      iframeNodes,
+      frameOwnerBackendNodeIds,
+      frameParentIds,
+      excludedBackendNodeIds,
+      frameGeometryIssues,
+    };
   }
 
   const parentBackendIds = parentDoc?.nodes?.backendNodeId ?? [];
-  const parentNodeByBackendId = new Map(parentNodes.map((node) => [node.backendNodeId, node]));
 
-  for (const [nodeArrayIdx, childDocIndex] of cdi) {
-    if (visited.has(childDocIndex)) continue;
+  const children = [...cdi].flatMap(([nodeArrayIdx, childDocIndex]) => {
     const childDoc = documents[childDocIndex];
-    if (!childDoc) continue;
     const iframeBackendId = parentBackendIds[nodeArrayIdx];
-    if (iframeBackendId === undefined) continue;
-    const iframeNode = parentNodeByBackendId.get(iframeBackendId);
-    const projection =
-      parentContext.projection && iframeNode?.localRect
-        ? childFrameProjection(parentContext.projection, iframeNode.localRect)
-        : null;
+    if (visited.has(childDocIndex) || !childDoc || iframeBackendId === undefined) return [];
+    const source = { target: parentContext.target, frameId: snapshotFrameId(childDoc, strings) };
+    const coordinates = snapshotCoordinates(childDoc, parentContext.layoutUnitsPerCssPixel);
+    const parent = parentContext.projection;
+    const projection: FrameProjectionState =
+      parent.status === "available"
+        ? coordinates
+          ? { status: "unavailable", source, ownerBackendNodeId: iframeBackendId }
+          : { status: "unavailable", source, reason: "snapshot-coordinates-unavailable" }
+        : { status: "blocked", source, cause: parent.status === "blocked" ? parent.cause : parent };
+    return [
+      {
+        childDocIndex,
+        childDoc,
+        iframeBackendId,
+        source,
+        coordinates,
+        projection: projection as FrameProjectionState,
+      },
+    ];
+  });
+  const parentProjection =
+    parentContext.projection.status === "available"
+      ? parentContext.projection.projection.geometry
+      : null;
+  if (parentProjection) {
+    // Measure only direct siblings. Recursion starts after these workers finish,
+    // so descendants never hold or recursively acquire a measurement slot.
+    const edge = parentProjection.edges[0];
+    const clips = edge
+      ? [edge.destinationQuad, ...(edge.destinationClips ?? [])]
+      : parentProjection.sourceClips;
+    let cursor = 0;
+    let failure: unknown;
+    await Promise.all(
+      Array.from({ length: Math.min(4, children.length) }, async () => {
+        while (cursor < children.length && !signal?.aborted && !failure) {
+          const child = children[cursor++];
+          if (!child.coordinates) continue;
+          try {
+            // Owner quads are target-relative; do not apply the parent transform twice.
+            child.projection = await geometry.snapshotProjection(
+              child.source,
+              child.iframeBackendId,
+              clips,
+              parentProjection.topViewport,
+            );
+          } catch (error) {
+            failure ??= error;
+          }
+        }
+      }),
+    );
+    // Join all active reads, including object cleanup, before propagating abort.
+    if (failure) throw failure;
+  }
+  throwIfAborted(signal);
 
+  // Completion order must not change document traversal or result insertion order.
+  for (const {
+    childDocIndex,
+    childDoc,
+    iframeBackendId,
+    source,
+    projection,
+    coordinates,
+  } of children) {
+    throwIfAborted(signal);
+    if (projection.status !== "available") frameGeometryIssues.push(projection);
     const childContext: FrameContext = {
-      frameId: snapshotFrameId(childDoc, strings),
+      frameId: source.frameId,
+      target: source.target,
       ownerFrameBackendNodeId: iframeBackendId,
       projection,
-      scrollX: childDoc.scrollOffsetX ?? 0,
-      scrollY: childDoc.scrollOffsetY ?? 0,
+      coordinates,
+      layoutUnitsPerCssPixel: parentContext.layoutUnitsPerCssPixel,
     };
     const nextVisited = new Set(visited);
     nextVisited.add(childDocIndex);
-    const parsed = parseDocumentNodes(childDoc, strings, dpr, childContext);
+    const parsed = parseDocumentNodes(childDoc, strings, childContext);
     iframeNodes.set(iframeBackendId, parsed.nodes);
     if (childContext.frameId) {
       frameOwnerBackendNodeIds.set(childContext.frameId, iframeBackendId);
@@ -1031,15 +1104,16 @@ function parseChildFrameDocuments(
     }
     for (const id of parsed.excludedBackendNodeIds) excludedBackendNodeIds.add(id);
 
-    const nested = parseChildFrameDocuments(
+    const nested = await parseChildFrameDocuments(
       documents,
       strings,
-      dpr,
       childDocIndex,
-      parsed.nodes,
       childContext,
+      geometry,
+      signal,
       nextVisited,
     );
+    frameGeometryIssues.push(...nested.frameGeometryIssues);
     for (const [nestedFrameId, nestedNodes] of nested.iframeNodes) {
       iframeNodes.set(nestedFrameId, nestedNodes);
     }
@@ -1052,7 +1126,13 @@ function parseChildFrameDocuments(
     for (const id of nested.excludedBackendNodeIds) excludedBackendNodeIds.add(id);
   }
 
-  return { iframeNodes, frameOwnerBackendNodeIds, frameParentIds, excludedBackendNodeIds };
+  return {
+    iframeNodes,
+    frameOwnerBackendNodeIds,
+    frameParentIds,
+    excludedBackendNodeIds,
+    frameGeometryIssues,
+  };
 }
 
 export async function captureViewModel(
@@ -1061,22 +1141,21 @@ export async function captureViewModel(
   options: CaptureViewModelOptions = {},
 ): Promise<CapturedViewModel> {
   throwIfAborted(options.signal);
-  let metrics: LayoutMetricsReply = {};
+  const target = options.target ?? { tabId };
+  const geometry = options.geometry ?? new GeometryContext(cdp, tabId, undefined, options.signal);
+  let metrics: LayoutMetrics = {};
   try {
-    metrics = await cdp.send<LayoutMetricsReply>(tabId, "Page.getLayoutMetrics", {});
+    metrics = await geometry.layoutMetrics(target);
   } catch (error) {
     if (isAbortError(error)) throw error;
     console.debug("[bsk capture] layout metrics unavailable", error);
   }
   throwIfAborted(options.signal);
-  const dpr = devicePixelRatio(metrics);
-  const vpSrc = metrics.cssLayoutViewport ?? metrics.layoutViewport ?? {};
   const viewport: Viewport = {
-    width: vpSrc.clientWidth ?? 0,
-    height: vpSrc.clientHeight ?? 0,
+    width: metrics.cssLayoutViewport?.clientWidth ?? 0,
+    height: metrics.cssLayoutViewport?.clientHeight ?? 0,
   };
-  const scrollX = vpSrc.pageX ?? 0;
-  const scrollY = vpSrc.pageY ?? 0;
+  const layoutUnitsPerCssPixel = snapshotLayoutScale(metrics);
 
   await cdp.send(tabId, "DOMSnapshot.enable", {});
   throwIfAborted(options.signal);
@@ -1099,22 +1178,49 @@ export async function captureViewModel(
     };
   }
 
+  const source = { target, frameId: snapshotFrameId(doc0, strings) };
+  const coordinates = snapshotCoordinates(doc0, layoutUnitsPerCssPixel, {
+    x: metrics.cssLayoutViewport?.pageX,
+    y: metrics.cssLayoutViewport?.pageY,
+  });
   const topContext: FrameContext = {
     frameId: snapshotFrameId(doc0, strings),
     ownerFrameBackendNodeId: null,
-    projection: {
-      sourceClips: [],
-      edges: [],
-      topViewport: viewport,
-    },
-    scrollX,
-    scrollY,
+    target,
+    projection:
+      coordinates &&
+      [viewport.width, viewport.height].every((size) => Number.isFinite(size) && size > 0)
+        ? {
+            status: "available",
+            projection: {
+              source,
+              geometry: { sourceClips: [], edges: [], topViewport: viewport },
+            },
+          }
+        : { status: "unavailable", source, reason: "snapshot-coordinates-unavailable" },
+    coordinates,
+    layoutUnitsPerCssPixel,
   };
-  const mainParsed = parseDocumentNodes(doc0, strings, dpr, topContext);
+  const mainParsed = parseDocumentNodes(doc0, strings, topContext);
   const nodes = mainParsed.nodes;
   const excludedBackendNodeIds = new Set(mainParsed.excludedBackendNodeIds);
 
-  const frameParsed = parseChildFrameDocuments(documents, strings, dpr, 0, nodes, topContext);
+  const ownerIds = new Set<number>();
+  for (const document of documents) {
+    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 frameParsed = await parseChildFrameDocuments(
+    documents,
+    strings,
+    0,
+    topContext,
+    geometry,
+    options.signal,
+  );
   const iframeNodes = frameParsed.iframeNodes;
   for (const id of frameParsed.excludedBackendNodeIds) {
     excludedBackendNodeIds.add(id);
@@ -1140,6 +1246,10 @@ export async function captureViewModel(
     viewport,
     iframeNodes,
     frameNodes,
+    frameGeometryIssues: [
+      ...(topContext.projection.status === "available" ? [] : [topContext.projection]),
+      ...frameParsed.frameGeometryIssues,
+    ],
     frameOwnerBackendNodeIds: frameParsed.frameOwnerBackendNodeIds,
     frameParentIds: frameParsed.frameParentIds,
     ...(topContext.frameId ? { rootFrameId: topContext.frameId } : {}),

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

@@ -1,6 +1,6 @@
 import type { CdpFrame, CdpFrameGraph } from "@/browser-driver/frame-graph";
-import { resolveFrameProjection } from "../frame-geometry";
 import { type GeometryProjection, projectRectToViewport } from "../geometry";
+import { GeometryContext } from "../geometry/frame-context";
 import { type CdpRunner, cdpRunnerForTarget, sendToCdpTarget } from "../shared";
 import { type CapturedNode, type CapturedViewModel, captureViewModel } from "./capture";
 import {
@@ -21,16 +21,6 @@ function isAbortError(err: unknown): boolean {
   return err instanceof Error && err.name === "AbortError";
 }
 
-async function discoverFrameGraph(cdp: CdpRunner, tabId: number): Promise<CdpFrameGraph | null> {
-  if (!cdp.getFrameGraph) return null;
-  try {
-    return await cdp.getFrameGraph(tabId);
-  } catch (err) {
-    console.debug("[bsk observation] frame graph capture failed", err);
-    return null;
-  }
-}
-
 function transformFrameNodes(
   nodes: CapturedNode[],
   projection: GeometryProjection | null,
@@ -51,6 +41,7 @@ async function captureMissingFrameDocuments(
   tabId: number,
   graph: CdpFrameGraph,
   captured: CapturedViewModel,
+  geometry: GeometryContext,
   signal?: AbortSignal,
 ): Promise<void> {
   if (!captured.frameNodes) captured.frameNodes = new Map();
@@ -62,10 +53,15 @@ async function captureMissingFrameDocuments(
     try {
       const child = await captureViewModel(cdpRunnerForTarget(cdp, frame.target), tabId, {
         signal,
+        geometry,
+        target: frame.target,
       });
+      if (child.frameGeometryIssues?.length) {
+        (captured.frameGeometryIssues ??= []).push(...child.frameGeometryIssues);
+      }
       let projection: GeometryProjection | null = null;
       try {
-        projection = await resolveFrameProjection(cdp, graph, frame.frameId);
+        projection = await geometry.targetProjection(frame.frameId);
       } catch (err) {
         if (isAbortError(err)) throw err;
         console.debug("[bsk observation] child frame geometry projection failed", {
@@ -171,10 +167,11 @@ export async function captureFrameData<T extends FrameAxNode>(
   tabId: number,
   captured: CapturedViewModel,
   signal?: AbortSignal,
+  geometry = new GeometryContext(cdp, tabId, undefined, signal),
 ): Promise<CapturedFrameDocument<T>[]> {
-  const graph = await discoverFrameGraph(cdp, tabId);
+  const graph = await geometry.graph();
   const frames = graph?.frames ?? [];
-  if (graph) await captureMissingFrameDocuments(cdp, tabId, graph, captured, signal);
+  if (graph) await captureMissingFrameDocuments(cdp, tabId, graph, captured, geometry, signal);
   throwIfAborted(signal);
   const batches = await captureAxTrees<T>(cdp, tabId, frames, captured, signal);
   return buildFrameDocuments(graph, batches, captured);

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/snapshot-coordinates/README.md

@@ -0,0 +1,44 @@
+# 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.
+
+## Separate existing boundary
+
+The OOPIF root uses non-occupying scrollbars in the unit-conversion regression. Root and
+same-process frames retain normal scrollbars. Append `&classic-scrollbars` to the fixture URL
+to reproduce the separate existing OOPIF projection issue: `targetProjection()` maps the CSS
+layout viewport (which excludes occupying scrollbars) onto the entire owner content quad.
+This inflates the projected coordinates when scrollbars occupy space. Main already has that
+mapping; fixing it also changes shared live geometry and is outside this snapshot-unit fix.
+The test does not relax its numeric tolerance to absorb that error.

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 +41,22 @@ test("case manifests are discovered, ordered, and grouped into suites", () => {
       "diagnostics",
       "mobile-emulation",
       "generated-form",
+      "snapshot-coordinates",
     ],
   );
-  assert.deepEqual(repositorySummary(cases, fixtureRegistry).suites, { core: 6, matrix: 1 });
+  assert.deepEqual(repositorySummary(cases, fixtureRegistry).suites, {
+    core: 6,
+    matrix: 1,
+    regression: 1,
+  });
 });
 
 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, 8);
+  assert.equal(summary.fixtureModules, 9);
+  assert.equal(summary.fixtureRoutes, 15);
 });
 
 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 {
@@ -64,7 +65,7 @@ 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"
@@ -90,30 +91,59 @@ function Add-ToSessionPath {
 # ── 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, $staged)
+        if ([System.IO.File]::Exists($Target)) {
+            # Use the downloaded CLI: older versions have broken Windows
+            # liveness checks. Stop verifies daemon identity before terminating it.
+            & $Source daemon stop
+            if ($LASTEXITCODE -ne 0) { throw "could not stop bsk daemon; existing installation was not replaced" }
+            # PowerShell 5.1 converts $null to an empty path for string parameters.
+            [System.IO.File]::Replace($staged, $Target, [NullString]::Value)
+            Write-Log "daemon will restart automatically on the next browser command"
+        }
+        else {
+            [System.IO.File]::Move($staged, $Target)
+        }
+    }
+    finally {
+        if ([System.IO.File]::Exists($staged)) { [System.IO.File]::Delete($staged) }
+    }
+}
+
 function Main {
     $platform = Get-PlatformTriple
 
@@ -184,7 +214,7 @@ function Main {
             New-Item -ItemType Directory -Path $InstallDir -Force | 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"
 
@@ -199,12 +229,8 @@ 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" }
 
         Write-Log "done"
         Write-Host ""

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 +1,135 @@
+#Requires -Version 5.1
+param([string]$BskPath = (Join-Path $PSScriptRoot "../target/debug/bsk.exe"))
+$ErrorActionPreference = "Stop"
+
+# Load definitions, never Main: no downloads or changes to the real user PATH.
+$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) {
+    $failed = $false
+    try { & $Action } catch { $failed = $true }
+    if (-not $failed) { throw "expected failure" }
+}
+
+$dir = 'C:\Users\Alice\.local\bin'
+foreach ($existing in @('', 'C:\WindowsApps', 'C:\A;C:\B')) {
+    $script:UserPath = $existing
+    Add-ToUserPath $dir
+    $expected = if ($existing) { "$existing;$dir" } else { $dir }
+    Assert-Equal $script:UserPath $expected
+    Add-ToUserPath $dir
+    Assert-Equal $script:UserPath $expected
+}
+
+$root = Join-Path ([IO.Path]::GetTempPath()) ("bsk-install-test-" + [Guid]::NewGuid().ToString('N'))
+[IO.Directory]::CreateDirectory($root) | Out-Null
+$oldBskHome = $env:BSK_HOME
+$oldAutoUpdate = $env:BSK_AUTO_UPDATE
+$daemon = $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"
+    $env:BSK_AUTO_UPDATE = "off"
+    [IO.Directory]::CreateDirectory($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"
+    Install-Binary $source $target
+    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" }
+
+    # 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 }
+    Assert-Equal (Get-FileHash -LiteralPath $target).Hash $before
+    [IO.File]::Delete($infoPath)
+
+    # 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 $targetDir -Filter "*.install-*").Count) { throw "staging files leaked" }
+    Write-Host "Windows installer regressions passed ($($PSVersionTable.PSVersion))"
+}
+catch {
+    Write-Host ($_ | Out-String)
+    Write-Host $_.ScriptStackTrace
+    throw
+}
+finally {
+    if ($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
+    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`;
     }
   }