test(geometry): identify the regression browser attachment

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

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

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

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

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

@@ -1,10 +1,8 @@
 // @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";
+import { captureObservationFacts } from "../vom/capture-coordinator";
 
 type Send = <T = Record<string, unknown>>(
   method: string,
@@ -132,6 +130,7 @@ describe.skipIf(!process.env.BSK_GEOMETRY_CHROME)("real DOMSnapshot coordinate c
               return send(method, params, sessionFor(target));
             },
             getFrameGraph: async () => graph,
+            getAttachmentId: () => rootSession,
           };
           const oracles = new Map<string, Oracle>();
           for (const frame of frames) {
@@ -180,14 +179,12 @@ describe.skipIf(!process.env.BSK_GEOMETRY_CHROME)("real DOMSnapshot coordinate c
             );
             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([]);
+          const facts = await captureObservationFacts(cdp, 1);
+          expect(facts.issues).toEqual([]);
           for (const frame of frames) {
-            const node = captured.frameNodes
-              ?.get(frame.frameId)
-              ?.find((node) => node.attrs.id === "probe");
+            const node = facts.documents
+              .find((doc) => doc.frame.frameId === frame.frameId)
+              ?.domNodes.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 };
@@ -206,7 +203,7 @@ describe.skipIf(!process.env.BSK_GEOMETRY_CHROME)("real DOMSnapshot coordinate c
                 frame: names.get(frame.frameId),
                 local,
                 top,
-                viewport: captured.viewport,
+                viewport: facts.viewport,
               }),
             ).not.toBeNull();
             for (const key of ["x", "y", "w", "h"] as const) {

apps/extension/src/tools/observation.ts

@@ -1,3 +1,4 @@
+import type { CapturedSceneInput } from "./vom/facts";
 // Observation handlers — `tool.snapshot`, `tool.get_html`, `tool.screenshot`,
 // and semantic `tool.observe` (design §7). Each handler resolves the target
 // tab (defaulting to the Agent Window's active tab when omitted) and
@@ -35,7 +36,6 @@ 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,
@@ -49,15 +49,9 @@ import {
   type ToolEffect,
 } from "./shared";
 import { resolveSnapshotRef } from "./snapshot-ref";
-import {
-  type CapturedNode,
-  type CapturedSurfaceProbe,
-  type CapturedViewModel,
-  captureViewModel,
-  collectOverlayExcludedBackendIds,
-  probeHoverSurfaces,
-} from "./vom/capture";
-import { type CapturedFrameDocument, captureFrameData } from "./vom/frame-capture";
+import { type CapturedNode, type CapturedSurfaceProbe, probeHoverSurfaces } from "./vom/capture";
+import { captureObservationFacts, semanticCapture } from "./vom/capture-coordinator";
+import type { FrameDocument as CapturedFrameDocument } from "./vom/frame-document";
 import { withOverlayBypass } from "./vom/hover-perception";
 import { probeTooltipNames } from "./vom/name-enrichment";
 import {
@@ -531,7 +525,7 @@ function buildActiveScopeBlocks(nodes: VomNode[], signals: VomNodeDomSignals): A
 
 function buildConditionalSurfaces(
   nodes: VomNode[],
-  captured: CapturedViewModel,
+  captured: CapturedSceneInput,
   probes: CapturedSurfaceProbe[],
 ): CondSurface[] {
   if (probes.length === 0) return [];
@@ -661,161 +655,9 @@ export interface BuildVomSceneOptions {
 
 export type VomFrameDocument = CapturedFrameDocument<CdpAxNode>;
 
-function legacyFrameDocuments(
-  axNodes: CdpAxNode[],
-  captured: CapturedViewModel,
-  pageUrl?: string,
-  rootTarget: VomFrameDocument["target"] = { tabId: 0 },
-): VomFrameDocument[] {
-  const rootFrameId = captured.rootFrameId ?? "root";
-  const documents: VomFrameDocument[] = [
-    {
-      frameId: rootFrameId,
-      contextScopeId: rootFrameId,
-      target: rootTarget,
-      ...(pageUrl ? { url: pageUrl } : {}),
-      axNodes: [],
-      domNodes: captured.nodes.map((node) => ({ ...node, frameId: node.frameId ?? rootFrameId })),
-    },
-  ];
-  const pending = [...captured.iframeNodes.entries()];
-  let progress = true;
-  let nextSyntheticFrame = 1;
-  while (pending.length > 0 && progress) {
-    progress = false;
-    for (let index = pending.length - 1; index >= 0; index -= 1) {
-      const [ownerBackendNodeId, domNodes] = pending[index];
-      const parent = documents.find((document) =>
-        document.domNodes.some((node) => node.backendNodeId === ownerBackendNodeId),
-      );
-      if (!parent) continue;
-      const frameId =
-        domNodes.find((node) => node.frameId)?.frameId ?? `legacy-frame-${nextSyntheticFrame++}`;
-      documents.push({
-        frameId,
-        parentFrameId: parent.frameId,
-        ownerBackendNodeId,
-        contextScopeId: frameId,
-        target: parent.target,
-        axNodes: [],
-        domNodes: domNodes.map((node) => ({ ...node, frameId: node.frameId ?? frameId })),
-      });
-      pending.splice(index, 1);
-      progress = true;
-    }
-  }
-
-  const documentByFrameId = new Map(documents.map((document) => [document.frameId, document]));
-  const backendFrame = new Map<number, string>();
-  const childFrameByOwner = new Map<number, string>();
-  for (const document of documents) {
-    if (document.ownerBackendNodeId !== undefined) {
-      childFrameByOwner.set(document.ownerBackendNodeId, document.frameId);
-    }
-    for (const node of document.domNodes) backendFrame.set(node.backendNodeId, document.frameId);
-  }
-  const axById = new Map(axNodes.map((node) => [node.nodeId, node]));
-  const ownership = new Map<string, string>();
-  const resolving = new Set<string>();
-  const frameForAx = (node: CdpAxNode): string => {
-    const cached = ownership.get(node.nodeId);
-    if (cached) return cached;
-    let frameId: string | undefined;
-    if (node.frameId && documentByFrameId.has(node.frameId)) frameId = node.frameId;
-    if (!frameId && typeof node.backendDOMNodeId === "number") {
-      frameId = backendFrame.get(node.backendDOMNodeId);
-    }
-    if (!frameId && node.parentId && !resolving.has(node.nodeId)) {
-      const parent = axById.get(node.parentId);
-      if (parent) {
-        frameId =
-          typeof parent.backendDOMNodeId === "number"
-            ? childFrameByOwner.get(parent.backendDOMNodeId)
-            : undefined;
-        if (!frameId) {
-          resolving.add(node.nodeId);
-          frameId = frameForAx(parent);
-          resolving.delete(node.nodeId);
-        }
-      }
-    }
-    frameId ??= rootFrameId;
-    ownership.set(node.nodeId, frameId);
-    return frameId;
-  };
-  for (const node of axNodes) frameForAx(node);
-  for (const node of axNodes) {
-    const frameId = ownership.get(node.nodeId) ?? rootFrameId;
-    const document = documentByFrameId.get(frameId) ?? documents[0];
-    document.axNodes.push({
-      ...node,
-      frameId,
-      ...(node.parentId && ownership.get(node.parentId) === frameId
-        ? { parentId: node.parentId }
-        : { parentId: undefined }),
-      ...(node.childIds
-        ? { childIds: node.childIds.filter((childId) => ownership.get(childId) === frameId) }
-        : {}),
-    });
-  }
-  return documents;
-}
-
-function withLegacyBackendIds(scene: VomScene): VomScene {
-  const used = new Set<number>();
-  const idMap = new Map<number, number>();
-  let nextVirtualId = -1;
-  for (const node of scene.nodes) {
-    const preferred = node.backendNodeId;
-    const id = preferred !== undefined && !used.has(preferred) ? preferred : nextVirtualId--;
-    used.add(id);
-    idMap.set(node.id, id);
-  }
-  return {
-    ...scene,
-    nodes: scene.nodes.map((node) => ({
-      ...node,
-      id: idMap.get(node.id) as number,
-      parentId: node.parentId === null ? null : (idMap.get(node.parentId) ?? null),
-      ...(node.domParentId !== undefined
-        ? { domParentId: node.domParentId === null ? null : (idMap.get(node.domParentId) ?? null) }
-        : {}),
-      ...(node.domAncestorIds
-        ? { domAncestorIds: node.domAncestorIds.flatMap((id) => idMap.get(id) ?? []) }
-        : {}),
-    })),
-    ...(scene.surfaces
-      ? {
-          surfaces: scene.surfaces.map((surface) => ({
-            ...surface,
-            triggerId: idMap.get(surface.triggerId) ?? surface.triggerId,
-          })),
-        }
-      : {}),
-    ...(scene.activeScopeBlocks
-      ? {
-          activeScopeBlocks: scene.activeScopeBlocks.map((block) => ({
-            ...block,
-            triggerId: idMap.get(block.triggerId) ?? block.triggerId,
-          })),
-        }
-      : {}),
-  };
-}
-
-export function buildVomScene(
-  axNodes: CdpAxNode[],
-  captured: CapturedViewModel,
-  options: BuildVomSceneOptions = {},
-): VomScene {
-  return withLegacyBackendIds(
-    buildFrameVomScene(legacyFrameDocuments(axNodes, captured, options.pageUrl), captured, options),
-  );
-}
-
 export function buildFrameVomScene(
   documents: VomFrameDocument[],
-  captured: CapturedViewModel,
+  captured: CapturedSceneInput,
   options: BuildVomSceneOptions = {},
 ): VomScene {
   const scene = buildSemanticVomScene({
@@ -831,7 +673,7 @@ export function buildFrameVomScene(
 function attachCapturedSceneAnnotations(
   scene: VomScene,
   documents: VomFrameDocument[],
-  captured: CapturedViewModel,
+  captured: CapturedSceneInput,
   surfaceProbes: CapturedSurfaceProbe[],
 ): VomScene {
   const rootDocument = documents.find((document) => document.frameId === scene.rootFrameId);
@@ -981,45 +823,6 @@ export async function handleGetHtml(
   }
 }
 
-function emptyCapturedViewModel(viewport = { width: 0, height: 0 }): CapturedViewModel {
-  return { viewport, nodes: [], iframeNodes: new Map(), excludedBackendNodeIds: new Set() };
-}
-
-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 geometry.layoutMetrics({ tabId });
-    throwIfAborted(signal, "observation");
-    const source = cssViewport(metrics);
-    viewport = { width: source.width, height: source.height };
-  } catch (error) {
-    if (isAbortError(error)) throw error;
-  }
-  const excludedBackendNodeIds = await collectOverlayExcludedBackendIds(cdp, tabId, signal);
-  throwIfAborted(signal, "observation");
-  return { ...emptyCapturedViewModel(viewport), excludedBackendNodeIds };
-}
-
-async function captureForVom(
-  cdp: CdpRunner,
-  tabId: number,
-  options: CaptureVomObservationOptions,
-  geometry: GeometryContext,
-): Promise<CapturedViewModel> {
-  try {
-    return await captureViewModel(cdp, tabId, { signal: options.signal, geometry });
-  } catch (error) {
-    if (isAbortError(error)) throw error;
-    return fallbackCapturedViewModel(cdp, tabId, geometry, options.signal);
-  }
-}
-
 export interface HoverProbeOutcome {
   /** Whether any active hover was dispatched during this observation. */
   performed: boolean;
@@ -1052,7 +855,7 @@ const NO_HOVER_PROBES: HoverProbeOutcome = {
 async function runHoverProbes(
   cdp: CdpRunner,
   tabId: number,
-  captured: CapturedViewModel,
+  captured: CapturedSceneInput,
   documents: VomFrameDocument[],
   staticSemantics: ReturnType<typeof resolveSemanticGraph>,
   options: CaptureVomObservationOptions,
@@ -1091,21 +894,9 @@ export async function captureVomObservation(
   throwIfAborted(options.signal, "observation");
   await cdp.ensureAttachedToUrl?.(tabId, url);
   throwIfAborted(options.signal, "observation");
-  const geometry = new GeometryContext(cdp, tabId, undefined, options.signal);
-  const captured = await captureForVom(cdp, tabId, options, geometry);
+  const facts = await captureObservationFacts<CdpAxNode>(cdp, tabId, options.signal, url);
+  const { captured, documents: normalizedDocuments } = semanticCapture(facts);
   throwIfAborted(options.signal, "observation");
-  const documents = await captureFrameData<CdpAxNode>(
-    cdp,
-    tabId,
-    captured,
-    options.signal,
-    geometry,
-  );
-  throwIfAborted(options.signal, "observation");
-  const normalizedDocuments =
-    documents.length === 1 && captured.iframeNodes.size > 0
-      ? legacyFrameDocuments(documents[0].axNodes, captured, url, documents[0].target)
-      : documents;
   const semanticGraph = buildSemanticGraph({
     documents: normalizedDocuments,
     viewport: captured.viewport,
@@ -1135,19 +926,41 @@ export async function captureVomObservation(
   );
   // Reserve space using the renderer's character-based token estimate. Like VOM
   // headers, this integrity notice remains visible even under a tiny token budget.
-  const geometryNotice = captured.frameGeometryIssues?.length
-    ? "@warning geometry incomplete: some page or frame content has no top-level coordinates.\n"
-    : "";
+  const notices: string[] = [];
+  if (facts.issues.some((issue) => issue.stage === "geometry"))
+    notices.push(
+      "@warning geometry incomplete: some page or frame content has no top-level coordinates.",
+    );
+  const incompleteStages = ["dom", "ax", "forms", "ownership"].filter((stage) =>
+    facts.issues.some((issue) => issue.stage === stage),
+  );
+  if (incompleteStages.length)
+    notices.push(
+      `@warning observation incomplete: some ${incompleteStages.join(", ")} data is unavailable or omitted.`,
+    );
+  if (
+    facts.issues.some(
+      (issue) => issue.stage === "identity" && issue.reason !== "identity-unverified",
+    )
+  )
+    notices.push(
+      "@warning observation incomplete: some documents were omitted because their identity changed or could not be revalidated.",
+    );
+  if (facts.issues.some((issue) => issue.reason === "identity-unverified"))
+    notices.push(
+      "@warning document identity unverified: some retained documents could not be checked for changes during capture.",
+    );
+  const captureNotice = notices.join("\n");
   const rendered = renderVom(decoratedScene, {
     maxDepth: options.maxDepth,
     maxTokens:
-      !geometryNotice || options.maxTokens === undefined
+      !captureNotice || options.maxTokens === undefined
         ? options.maxTokens
-        : Math.max(0, options.maxTokens - Math.ceil(geometryNotice.length / 4)),
+        : Math.max(0, options.maxTokens - Math.ceil((captureNotice.length + 1) / 4)),
     redactValues: options.redactValues,
     activeRegionPolicy: options.activeRegionPolicy,
   });
-  if (geometryNotice) rendered.text += `\n${geometryNotice.trimEnd()}`;
+  if (captureNotice) rendered.text += `\n${captureNotice}`;
   throwIfAborted(options.signal, "observation");
   return projectRecordSafeObservation({
     rootFrameId: captured.rootFrameId ?? normalizedDocuments[0]?.frameId ?? "root",

apps/extension/src/tools/shared.ts

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

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

@@ -1,7 +1,7 @@
 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";
+import { collectOverlayExcludedBackendIds, probeHoverSurfaces } from "../capture";
+import { captureObservationFacts, semanticCapture } from "../capture-coordinator";
 
 // Minimal but format-accurate captureSnapshot reply: a body with one
 // fixed full-screen overlay div carrying a password input.
@@ -27,6 +27,7 @@ function fakeSnapshotReply() {
     strings: S,
     documents: [
       {
+        frameId: "root",
         nodes: {
           parentIndex: [-1, 0, 1, 2],
           nodeType: [1, 1, 1, 1],
@@ -74,6 +75,7 @@ function hoverTriggerSnapshotReply() {
     strings: S,
     documents: [
       {
+        frameId: "root",
         nodes: {
           parentIndex: [-1, 0, 1],
           nodeType: [1, 1, 1],
@@ -118,6 +120,7 @@ function twoHoverTriggerSnapshotReply() {
     strings: S,
     documents: [
       {
+        frameId: "root",
         nodes: {
           parentIndex: [-1, 0, 1, 1],
           nodeType: [1, 1, 1, 1],
@@ -171,6 +174,7 @@ function nestedHoverTriggerSnapshotReply() {
     strings: S,
     documents: [
       {
+        frameId: "root",
         nodes: {
           parentIndex: [-1, 0, 1, 2, 3],
           nodeType: [1, 1, 1, 1, 1],
@@ -248,13 +252,11 @@ function makeCdp(snapshot: unknown) {
   };
 }
 
-describe("captureViewModel", () => {
+describe("snapshot capture and hover", () => {
   it("parses nodes, attrs, rects, paint order and styles", async () => {
-    const { nodes, viewport, iframeNodes } = await captureViewModel(
-      makeCdp(fakeSnapshotReply()),
-      4,
-    );
-    expect(iframeNodes.size).toBe(0);
+    const { nodes, viewport } = semanticCapture(
+      await captureObservationFacts(makeCdp(fakeSnapshotReply()), 4),
+    ).captured;
     expect(viewport).toEqual({ width: 1000, height: 800 });
     const div = nodes.find((n) => n.backendNodeId === 12);
     expect(div).toMatchObject({ tag: "div", position: "fixed", parentBackendNodeId: 11 });
@@ -266,35 +268,11 @@ describe("captureViewModel", () => {
 
   it("never hovers the page while capturing", async () => {
     const cdp = makeCdp(fakeSnapshotReply());
-    await captureViewModel(cdp, 4);
+    semanticCapture(await captureObservationFacts(cdp, 4)).captured;
 
     expect(cdp.send).not.toHaveBeenCalledWith(4, "Input.dispatchMouseEvent", expect.anything());
   });
 
-  it("batch-enriches form controls without per-node object resolution", async () => {
-    const cdp = makeCdp(fakeSnapshotReply());
-    const result = await captureViewModel(cdp, 4);
-    const input = result.nodes.find((node) => node.backendNodeId === 13);
-
-    expect(input).toMatchObject({
-      formState: "filled",
-      formPlaceholder: "secret",
-      attrs: { type: "password" },
-    });
-    expect(input?.formValue).toBeUndefined();
-    expect(input?.formDefaultValue).toBeUndefined();
-    expect(cdp.send).toHaveBeenCalledWith(
-      4,
-      "Runtime.evaluate",
-      expect.objectContaining({
-        serializationOptions: expect.objectContaining({ serialization: "deep" }),
-      }),
-    );
-    expect(cdp.send).toHaveBeenCalledWith(4, "Runtime.releaseObjectGroup", expect.anything());
-    expect(cdp.send).not.toHaveBeenCalledWith(4, "DOM.resolveNode", expect.anything());
-    expect(cdp.send).not.toHaveBeenCalledWith(4, "Runtime.callFunctionOn", expect.anything());
-  });
-
   it("runs hover surface probes when explicitly enabled", async () => {
     let hoverStateCalls = 0;
     const cdp = {
@@ -336,7 +314,7 @@ describe("captureViewModel", () => {
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
 
-    const captured = await captureViewModel(cdp, 4);
+    const captured = semanticCapture(await captureObservationFacts(cdp, 4)).captured;
     const surfaceProbes = await probeHoverSurfaces(cdp, 4, captured.nodes);
 
     expect(surfaceProbes).toEqual([
@@ -398,7 +376,7 @@ describe("captureViewModel", () => {
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
 
-    const captured = await captureViewModel(cdp, 4);
+    const captured = semanticCapture(await captureObservationFacts(cdp, 4)).captured;
     const surfaceProbes = await probeHoverSurfaces(cdp, 4, captured.nodes);
 
     expect(surfaceProbes).toEqual([
@@ -445,7 +423,7 @@ describe("captureViewModel", () => {
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
 
-    const captured = await captureViewModel(cdp, 4);
+    const captured = semanticCapture(await captureObservationFacts(cdp, 4)).captured;
     await probeHoverSurfaces(cdp, 4, captured.nodes);
 
     expect(hoverMoves).toBe(1);
@@ -477,6 +455,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1, 0, 3, 4],
             nodeName: [i("html"), i("body"), i("div"), i(OVERLAY_HOST_NAME), i("div"), i("button")],
@@ -507,7 +486,7 @@ describe("captureViewModel", () => {
       ],
     };
 
-    const { nodes } = await captureViewModel(makeCdp(snapshot), 4);
+    const { nodes } = semanticCapture(await captureObservationFacts(makeCdp(snapshot), 4)).captured;
     const ids = nodes.map((n) => n.backendNodeId);
     // Real page nodes survive.
     expect(ids).toContain(12);
@@ -538,6 +517,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1, 0, 3, 4],
             nodeName: [i("html"), i("body"), i("div"), i(OVERLAY_HOST_NAME), i("div"), i("button")],
@@ -568,7 +548,9 @@ describe("captureViewModel", () => {
       ],
     };
 
-    const { excludedBackendNodeIds } = await captureViewModel(makeCdp(snapshot), 4);
+    const { excludedBackendNodeIds } = semanticCapture(
+      await captureObservationFacts(makeCdp(snapshot), 4),
+    ).captured;
     expect(excludedBackendNodeIds).toEqual(new Set([13, 14, 15]));
   });
 
@@ -589,6 +571,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1],
             nodeName: [i("html"), i("body"), i(OVERLAY_HOST_NAME)],
@@ -611,7 +594,9 @@ describe("captureViewModel", () => {
       ],
     };
 
-    const { nodes, excludedBackendNodeIds } = await captureViewModel(makeCdp(snapshot), 4);
+    const { nodes, excludedBackendNodeIds } = semanticCapture(
+      await captureObservationFacts(makeCdp(snapshot), 4),
+    ).captured;
     expect(nodes.map((n) => n.backendNodeId)).not.toContain(13);
     expect(excludedBackendNodeIds).toEqual(new Set([13]));
   });
@@ -634,6 +619,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1],
             nodeName: [i("html"), i("body"), i("div")],
@@ -656,7 +642,9 @@ describe("captureViewModel", () => {
       ],
     };
 
-    const { nodes, excludedBackendNodeIds } = await captureViewModel(makeCdp(snapshot), 4);
+    const { nodes, excludedBackendNodeIds } = semanticCapture(
+      await captureObservationFacts(makeCdp(snapshot), 4),
+    ).captured;
     expect(nodes.map((n) => n.backendNodeId)).not.toContain(13);
     expect(excludedBackendNodeIds).toEqual(new Set([13]));
   });
@@ -679,6 +667,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1],
             nodeName: [i("html"), i("body"), i("div")],
@@ -701,7 +690,7 @@ describe("captureViewModel", () => {
         },
       ],
     };
-    const { nodes } = await captureViewModel(makeCdp(snapshot), 4);
+    const { nodes } = semanticCapture(await captureObservationFacts(makeCdp(snapshot), 4)).captured;
     expect(nodes.find((n) => n.backendNodeId === 12)?.cursor).toBe("pointer");
     expect(nodes.find((n) => n.backendNodeId === 11)?.cursor).toBe("auto");
   });
@@ -713,6 +702,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1, 1, 1],
             nodeName: [i("html"), i("body"), i("button"), i("button"), i("button")],
@@ -739,7 +729,7 @@ describe("captureViewModel", () => {
       ],
     };
 
-    const { nodes } = await captureViewModel(makeCdp(snapshot), 4);
+    const { nodes } = semanticCapture(await captureObservationFacts(makeCdp(snapshot), 4)).captured;
 
     expect(nodes.find((node) => node.backendNodeId === 12)?.rendered).toBe(true);
     expect(nodes.find((node) => node.backendNodeId === 13)?.rendered).toBe(false);
@@ -761,51 +751,12 @@ describe("captureViewModel", () => {
         throw new Error(method);
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
-    const { nodes } = await captureViewModel(cdp, 4);
+    const { nodes } = semanticCapture(await captureObservationFacts(cdp, 4)).captured;
     const div = nodes.find((n) => n.backendNodeId === 12);
     expect(div?.localRect?.y).toBe(-200);
     expect(div?.rect).toMatchObject({ y: 0, h: 600 });
   });
 
-  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);
@@ -813,6 +764,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1],
             nodeName: [i("html"), i("body"), i("div")],
@@ -849,7 +801,7 @@ describe("captureViewModel", () => {
         throw new Error(method);
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
-    const { nodes } = await captureViewModel(cdp, 4);
+    const { nodes } = semanticCapture(await captureObservationFacts(cdp, 4)).captured;
     expect(nodes.find((n) => n.backendNodeId === 12)?.rect).toEqual({
       x: 0,
       y: 0,
@@ -885,6 +837,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           scrollOffsetX: 0,
           scrollOffsetY: 0,
           nodes: {
@@ -925,7 +878,7 @@ describe("captureViewModel", () => {
         throw new Error(method);
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
-    const { nodes } = await captureViewModel(cdp, 4);
+    const { nodes } = semanticCapture(await captureObservationFacts(cdp, 4)).captured;
     const btn = nodes.find((n) => n.backendNodeId === 12);
     expect(btn?.textContent).toBe("登录");
     const link = nodes.find((n) => n.backendNodeId === 14);
@@ -935,7 +888,7 @@ describe("captureViewModel", () => {
     expect(body?.textContent).toBeUndefined();
   });
 
-  it("parses iframe sub-documents and returns iframeNodes keyed by iframe backendNodeId", async () => {
+  it("retains explicit iframe document ownership and projected nodes", async () => {
     const S = [
       "html",
       "body",
@@ -1023,30 +976,21 @@ describe("captureViewModel", () => {
         throw new Error(method);
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
-    const {
-      nodes,
-      iframeNodes,
-      frameNodes,
-      frameOwnerBackendNodeIds,
-      frameParentIds,
-      rootFrameId,
-    } = await captureViewModel(cdp, 4);
-    // Main frame has 4 nodes; iframe is included
-    expect(nodes.find((n) => n.backendNodeId === 13)?.tag).toBe("iframe");
-    // iframeNodes keyed by the <iframe> element's backendNodeId=13
-    expect(iframeNodes.size).toBe(1);
-    expect(iframeNodes.has(13)).toBe(true);
-    const subNodes = iframeNodes.get(13)!;
+    const facts = await captureObservationFacts(cdp, 4);
+    const root = facts.documents.find((doc) => doc.frame.frameId === "main-frame")!;
+    const child = facts.documents.find((doc) => doc.frame.frameId === "child-frame")!;
+    expect(facts.documents).toHaveLength(2);
+    expect(root.domNodes.find((n) => n.backendNodeId === 13)?.tag).toBe("iframe");
+    const subNodes = child.domNodes;
     const input = subNodes.find((n) => n.backendNodeId === 101);
     expect(input?.tag).toBe("input");
     expect(input?.attrs.type).toBe("text");
     expect(input?.ownerFrameBackendNodeId).toBe(13);
     expect(input?.localRect).toEqual({ x: 0, y: 0, w: 200, h: 40 });
     expect(input?.rect).toEqual({ x: 100, y: 300, w: 200, h: 40 });
-    expect(rootFrameId).toBe("main-frame");
-    expect(frameNodes?.get("child-frame")).toBe(subNodes);
-    expect(frameOwnerBackendNodeIds?.get("child-frame")).toBe(13);
-    expect(frameParentIds?.get("child-frame")).toBe("main-frame");
+    expect(facts.rootFrameId).toBe("main-frame");
+    expect(child.frame.ownerBackendNodeId).toBe(13);
+    expect(child.frame.parentFrameId).toBe("main-frame");
   });
 
   it("projects iframe documents independently of owner snapshot geometry", async () => {
@@ -1067,6 +1011,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           scrollOffsetX: 0,
           scrollOffsetY: 0,
           nodes: {
@@ -1084,6 +1029,7 @@ describe("captureViewModel", () => {
           },
         },
         {
+          frameId: "child",
           scrollOffsetX: 0,
           scrollOffsetY: 0,
           nodes: {
@@ -1122,8 +1068,10 @@ describe("captureViewModel", () => {
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
 
-    const { iframeNodes } = await captureViewModel(cdp, 4);
-    const input = iframeNodes.get(13)?.find((n) => n.backendNodeId === 101);
+    const { documents } = await captureObservationFacts(cdp, 4);
+    const input = documents
+      .find((doc) => doc.frame.frameId === "child")
+      ?.domNodes?.find((n) => n.backendNodeId === 101);
 
     expect(input?.localRect).toEqual({ x: 20, y: 20, w: 120, h: 60 });
     expect(input?.rect).toEqual({ x: 120, y: 320, w: 120, h: 60 });
@@ -1147,6 +1095,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1],
             nodeName: [i("html"), i("body"), i("iframe")],
@@ -1168,6 +1117,9 @@ describe("captureViewModel", () => {
           },
         },
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
+          frameId: "child",
           nodes: {
             parentIndex: [-1, 0, 1],
             nodeName: [i("html"), i("body"), i("iframe")],
@@ -1175,8 +1127,6 @@ describe("captureViewModel", () => {
             attributes: [[], [], []],
             contentDocumentIndex: { index: [2], value: [2] },
           },
-          scrollOffsetX: 0,
-          scrollOffsetY: 0,
           layout: {
             nodeIndex: [1, 2],
             styles: [
@@ -1191,14 +1141,15 @@ describe("captureViewModel", () => {
           },
         },
         {
+          scrollOffsetX: 0,
+          scrollOffsetY: 0,
+          frameId: "nested",
           nodes: {
             parentIndex: [-1, 0],
             nodeName: [i("body"), i("input")],
             backendNodeId: [30, 31],
             attributes: [[], [i("type"), i("text")]],
           },
-          scrollOffsetX: 0,
-          scrollOffsetY: 0,
           layout: {
             nodeIndex: [1],
             styles: [[i("static"), i("auto")]],
@@ -1250,9 +1201,13 @@ describe("captureViewModel", () => {
       ) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
 
-    const { iframeNodes } = await captureViewModel(cdp, 4);
-    const nestedIframe = iframeNodes.get(13)?.find((n) => n.backendNodeId === 23);
-    const input = iframeNodes.get(23)?.find((n) => n.backendNodeId === 31);
+    const { documents } = await captureObservationFacts(cdp, 4);
+    const nestedIframe = documents
+      .find((doc) => doc.frame.frameId === "child")
+      ?.domNodes?.find((n) => n.backendNodeId === 23);
+    const input = documents
+      .find((doc) => doc.frame.frameId === "nested")
+      ?.domNodes?.find((n) => n.backendNodeId === 31);
 
     expect(nestedIframe?.localRect).toEqual({ x: 5, y: 6, w: 100, h: 80 });
     expect(nestedIframe?.rect).toEqual({ x: 15, y: 26, w: 100, h: 80 });
@@ -1268,6 +1223,7 @@ describe("captureViewModel", () => {
       strings: S,
       documents: [
         {
+          frameId: "root",
           nodes: {
             parentIndex: [-1, 0, 1],
             nodeName: [i("html"), i("body"), i("div")],
@@ -1304,7 +1260,7 @@ describe("captureViewModel", () => {
         throw new Error(method);
       }) as unknown as <T>(tabId: number, method: string, params?: object) => Promise<T>,
     };
-    const { nodes } = await captureViewModel(cdp, 4);
+    const { nodes } = semanticCapture(await captureObservationFacts(cdp, 4)).captured;
     expect(nodes.find((n) => n.backendNodeId === 12)?.rect?.y).toBe(400 / 2 - 100);
   });
 
@@ -1330,200 +1286,3 @@ 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__/facts.test.ts

@@ -0,0 +1,127 @@
+import { describe, expect, it, vi } from "vitest";
+import { OVERLAY_HOST_MARKER_ATTR } from "@/lib/overlay-bridge";
+import { createCaptureCheckpoint } from "../capture-abort";
+import { buildDocumentIndex, type DecodedNode } from "../facts";
+import { decodeDocument, REQUESTED_STYLES } from "../snapshot";
+
+function node(id: number, parent: number | null): DecodedNode {
+  return {
+    backendNodeId: id,
+    parentBackendNodeId: parent,
+    tag: "div",
+    attrs: {},
+    paintOrder: 0,
+    position: "static",
+    pointerEvents: "auto",
+  };
+}
+
+describe("document facts", () => {
+  it.each([
+    1_000, 10_000, 100_000,
+  ])("indexes deep and wide inputs of %i without copying ancestors", async (count) => {
+    for (const wide of [false, true]) {
+      let reads = 0;
+      const input = Array.from({ length: count }, (_, i) => {
+        const item = node(i, i ? (wide ? 0 : i - 1) : null);
+        if (i === 0) item.attrs[OVERLAY_HOST_MARKER_ATTR] = "";
+        Object.defineProperty(item, "parentBackendNodeId", {
+          get: () => {
+            reads++;
+            return i ? (wide ? 0 : i - 1) : null;
+          },
+        });
+        return item;
+      }).reverse(); // parent need not precede child
+      const index = await buildDocumentIndex(input);
+      expect(index.nodes.size).toBe(count);
+      expect(index.excludedBackendNodeIds.size).toBe(count);
+      expect(reads).toBeLessThanOrEqual(count * 8);
+      expect(index.nodes.get(count - 1)).toBe(input[0]);
+    }
+  });
+
+  it("handles cycles and orphans and propagates overlay through shadow roots", async () => {
+    const host = { ...node(1, null), attrs: { [OVERLAY_HOST_MARKER_ATTR]: "" } };
+    const input = [
+      node(3, 2),
+      { ...node(2, 1), tag: "#document-fragment" },
+      host,
+      node(4, 99),
+      node(5, 6),
+      node(6, 5),
+      node(7, 6),
+    ];
+    const index = await buildDocumentIndex(input);
+    expect([...index.excludedBackendNodeIds].sort()).toEqual([1, 2, 3]);
+    expect(index.nodes.size).toBe(input.length);
+  });
+
+  it("does not propagate a descendant overlay backwards into a cycle", async () => {
+    const overlay = { ...node(3, 1), attrs: { [OVERLAY_HOST_MARKER_ATTR]: "" } };
+    const index = await buildDocumentIndex([overlay, node(1, 2), node(2, 1)]);
+    expect([...index.excludedBackendNodeIds]).toEqual([3]);
+  });
+
+  it("decodes current observation bounds, styles and attributes without projecting coordinates", async () => {
+    const strings = ["div", "aria-hidden", "true", "inert", "", "visible", "0", "static", "auto"];
+    const styles = REQUESTED_STYLES.map((style) =>
+      style === "visibility" ? 5 : style === "opacity" ? 6 : style === "position" ? 7 : 8,
+    );
+    const { nodes } = await decodeDocument(
+      {
+        nodes: { backendNodeId: [1], parentIndex: [-1], nodeName: [0], attributes: [[1, 2, 3, 4]] },
+        layout: { nodeIndex: [0], bounds: [[10, 20, 120, 40]], styles: [styles] },
+      },
+      strings,
+    );
+    expect(nodes[0].attrs).toEqual({ "aria-hidden": "true", inert: "" });
+    expect(nodes[0].layout).toEqual({
+      boundsSpace: "snapshot-document-layout",
+      bounds: [10, 20, 120, 40],
+      styles: {
+        position: "static",
+        "pointer-events": "auto",
+        cursor: "auto",
+        visibility: "visible",
+        opacity: "0",
+      },
+    });
+    expect(nodes[0]).not.toHaveProperty("rect");
+    expect(nodes[0]).not.toHaveProperty("excluded");
+  });
+
+  it("keeps short blocks synchronous and checks cancellation after yielding", async () => {
+    const clock = vi.spyOn(performance, "now").mockReturnValue(0);
+    try {
+      const controller = new AbortController();
+      const checkpoint = createCaptureCheckpoint(controller.signal);
+      for (let i = 0; i < 20; i++) expect(checkpoint()).toBeUndefined();
+      clock.mockReturnValue(9);
+      const pending = checkpoint();
+      expect(pending).toBeInstanceOf(Promise);
+      controller.abort();
+      await expect(pending).rejects.toMatchObject({ name: "AbortError" });
+    } finally {
+      clock.mockRestore();
+    }
+  });
+
+  it("checks cancellation at bounded indexing blocks", async () => {
+    const controller = new AbortController();
+    const input = Array.from({ length: 100_000 }, (_, i) => node(i, i ? i - 1 : null));
+    let reads = 0;
+    for (const item of input)
+      Object.defineProperty(item, "attrs", {
+        get: () => {
+          reads++;
+          if (reads === 100) controller.abort();
+          return {};
+        },
+      });
+    await expect(buildDocumentIndex(input, controller.signal)).rejects.toMatchObject({
+      name: "AbortError",
+    });
+    expect(reads).toBeLessThanOrEqual(356);
+  });
+});

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

@@ -1,6 +1,7 @@
 import { describe, expect, it, vi } from "vitest";
 import { type CdpRunner, cdpRunnerForTarget } from "../../shared";
-import { captureViewModel } from "../capture";
+import { enrichFormControlStates } from "../form-capture";
+import { decodeDocument } from "../snapshot";
 
 interface Control {
   id: number;
@@ -77,21 +78,32 @@ function reply(entries: Array<[number, unknown]>) {
   };
 }
 
-function fakeCdp(groups: Control[][], evaluate: (params: Record<string, unknown>) => unknown) {
+async function fakeCdp(
+  groups: Control[][],
+  evaluate: (params: Record<string, unknown>) => unknown,
+) {
   const snap = snapshot(groups);
   const send = vi.fn(async (_tabId: number, method: string, params?: object) => {
-    if (method === "DOMSnapshot.captureSnapshot") return snap;
     if (method === "Runtime.evaluate") return evaluate(params as Record<string, unknown>);
     return {};
   });
-  return { send, cdp: { send: send as CdpRunner["send"] } };
+  const nodes = await decodeControls(snap);
+  return { send, cdp: { send: send as CdpRunner["send"] }, nodes };
+}
+
+async function decodeControls(snap: ReturnType<typeof snapshot>) {
+  return Promise.all(
+    snap.documents.map(async (doc) =>
+      (await decodeDocument(doc, snap.strings)).nodes.map((node) => ({ ...node, rect: null })),
+    ),
+  );
 }
 
 describe("form state identity", () => {
   it("matches reordered controls by identity and preserves controls missing from the batch", async () => {
     // The snapshot includes a shadow input. The runtime query skips it,
     // encounters a new input, and sees the remaining inputs in a new order.
-    const { cdp } = fakeCdp(
+    const { cdp, nodes } = await fakeCdp(
       [
         [
           { id: 10, value: "" },
@@ -106,21 +118,21 @@ describe("form state identity", () => {
           [11, state("alice@example.com")],
         ]),
     );
-    const captured = await captureViewModel(cdp, 7);
-    expect(captured.nodes.find((n) => n.backendNodeId === 10)).toMatchObject({
+    await enrichFormControlStates(cdp, 7, nodes);
+    expect(nodes[0].find((n) => n.backendNodeId === 10)).toMatchObject({
       formValue: "",
       formState: "empty",
       formPlaceholder: "snapshot placeholder",
     });
-    expect(captured.nodes.find((n) => n.backendNodeId === 11)).toMatchObject({
+    expect(nodes[0].find((n) => n.backendNodeId === 11)).toMatchObject({
       formValue: "alice@example.com",
     });
-    expect(captured.nodes.find((n) => n.backendNodeId === 12)).toMatchObject({ formValue: "上海" });
-    expect(captured.nodes.some((n) => n.backendNodeId === 99)).toBe(false);
+    expect(nodes[0].find((n) => n.backendNodeId === 12)).toMatchObject({ formValue: "上海" });
+    expect(nodes[0].some((n) => n.backendNodeId === 99)).toBe(false);
   });
 
   it("does not shift state between frames when one frame is absent from the runtime batch", async () => {
-    const { cdp } = fakeCdp(
+    const { cdp, nodes } = await fakeCdp(
       [
         [],
         [{ id: 11, value: "inaccessible frame" }],
@@ -133,8 +145,8 @@ describe("form state identity", () => {
           [21, state("second frame")],
         ]),
     );
-    const captured = await captureViewModel(cdp, 7);
-    const controls = [...captured.iframeNodes.values()].flat();
+    await enrichFormControlStates(cdp, 7, nodes);
+    const controls = nodes.slice(1).flat();
     expect(controls.find((n) => n.backendNodeId === 11)?.formValue).toBe("inaccessible frame");
     expect(controls.find((n) => n.backendNodeId === 21)?.formValue).toBe("second frame");
     expect(controls.find((n) => n.backendNodeId === 31)?.formValue).toBe("third frame");
@@ -142,7 +154,6 @@ describe("form state identity", () => {
 
   it("keeps identical backend ids in different OOPIF targets separate", async () => {
     const sendToTarget = vi.fn(async (target, method) => {
-      if (method === "DOMSnapshot.captureSnapshot") return snapshot([[{ id: 11, value: "old" }]]);
       if (method === "Runtime.evaluate") return reply([[11, state(target.sessionId)]]);
       return {};
     });
@@ -151,8 +162,9 @@ describe("form state identity", () => {
     });
     const cdp = { send, sendToTarget } as unknown as CdpRunner;
     for (const sessionId of ["left-frame", "right-frame"]) {
-      const captured = await captureViewModel(cdpRunnerForTarget(cdp, { tabId: 7, sessionId }), 7);
-      expect(captured.nodes.find((n) => n.backendNodeId === 11)?.formValue).toBe(sessionId);
+      const nodes = await decodeControls(snapshot([[{ id: 11, value: "old" }]]));
+      await enrichFormControlStates(cdpRunnerForTarget(cdp, { tabId: 7, sessionId }), 7, nodes);
+      expect(nodes[0].find((n) => n.backendNodeId === 11)?.formValue).toBe(sessionId);
       expect(sendToTarget).toHaveBeenCalledWith(
         { tabId: 7, sessionId },
         "Runtime.releaseObjectGroup",
@@ -168,7 +180,7 @@ describe("form state identity", () => {
     "malformed",
     "invalid-state",
   ])("preserves snapshot data when enrichment is %s", async (mode) => {
-    const { cdp, send } = fakeCdp([[{ id: 11, value: "snapshot value" }]], () => {
+    const { cdp, send, nodes } = await fakeCdp([[{ id: 11, value: "snapshot value" }]], () => {
       if (mode === "unsupported") throw new Error("serialization unsupported");
       if (mode === "legacy") return { result: { value: { controls: [state("wrong value")] } } };
       const result = reply([
@@ -178,8 +190,8 @@ describe("form state identity", () => {
         result.result.deepSerializedValue.value[0].value[1].value = "not json";
       return result;
     });
-    const captured = await captureViewModel(cdp, 7);
-    expect(captured.nodes.find((n) => n.backendNodeId === 11)).toMatchObject({
+    expect(await enrichFormControlStates(cdp, 7, nodes)).toBe(mode !== "unsupported");
+    expect(nodes[0].find((n) => n.backendNodeId === 11)).toMatchObject({
       formValue: "snapshot value",
       formPlaceholder: "snapshot placeholder",
     });
@@ -188,18 +200,34 @@ describe("form state identity", () => {
 
   it("releases the batch's remote objects when capture is cancelled", async () => {
     const controller = new AbortController();
-    const { cdp, send } = fakeCdp([[{ id: 11, value: "old" }]], () => {
+    const { cdp, send, nodes } = await fakeCdp([[{ id: 11, value: "old" }]], () => {
       controller.abort();
       return reply([[11, state("new")]]);
     });
-    await expect(captureViewModel(cdp, 7, { signal: controller.signal })).rejects.toMatchObject({
+    await expect(enrichFormControlStates(cdp, 7, nodes, controller.signal)).rejects.toMatchObject({
       name: "AbortError",
     });
     expect(send).toHaveBeenCalledWith(7, "Runtime.releaseObjectGroup", expect.anything());
   });
 
+  it("does not report success when cancelled during object cleanup", async () => {
+    const controller = new AbortController();
+    const nodes = await decodeControls(snapshot([[{ id: 11, value: "old" }]]));
+    const cdp: CdpRunner = {
+      send: vi.fn(async (_tabId, method) => {
+        if (method === "Runtime.evaluate") return reply([[11, state("new")]]);
+        if (method === "Runtime.releaseObjectGroup") controller.abort();
+        return {};
+      }) as CdpRunner["send"],
+    };
+    await expect(enrichFormControlStates(cdp, 7, nodes, controller.signal)).rejects.toMatchObject({
+      name: "AbortError",
+    });
+    expect(cdp.send).toHaveBeenCalledWith(7, "Runtime.releaseObjectGroup", expect.anything());
+  });
+
   it("skips entries without node identity while still applying valid entries", async () => {
-    const { cdp } = fakeCdp(
+    const { cdp, nodes } = await fakeCdp(
       [
         [
           { id: 11, value: "snapshot value" },
@@ -216,20 +244,20 @@ describe("form state identity", () => {
         return result;
       },
     );
-    const captured = await captureViewModel(cdp, 7);
-    expect(captured.nodes.find((n) => n.backendNodeId === 11)?.formValue).toBe("snapshot value");
-    expect(captured.nodes.find((n) => n.backendNodeId === 12)?.formValue).toBe("live value");
+    await enrichFormControlStates(cdp, 7, nodes);
+    expect(nodes[0].find((n) => n.backendNodeId === 11)?.formValue).toBe("snapshot value");
+    expect(nodes[0].find((n) => n.backendNodeId === 12)?.formValue).toBe("live value");
   });
 
   it.each([
     "password",
     "text",
   ])("redacts a sensitive %s control after identity matching", async (type) => {
-    const { cdp } = fakeCdp([[{ id: 11, value: "secret", type }]], () =>
+    const { cdp, nodes } = await fakeCdp([[{ id: 11, value: "secret", type }]], () =>
       reply([[11, { ...state("secret"), sensitive: true }]]),
     );
-    const captured = await captureViewModel(cdp, 7);
-    const control = captured.nodes.find((n) => n.backendNodeId === 11);
+    await enrichFormControlStates(cdp, 7, nodes);
+    const control = nodes[0].find((n) => n.backendNodeId === 11);
     expect(control?.formState).toBe("filled");
     expect(control?.formValue).toBeUndefined();
     expect(control?.formDefaultValue).toBeUndefined();
@@ -246,7 +274,7 @@ describe("form state identity", () => {
       defaultValue: "",
       placeholder: "",
     }));
-    const { cdp, send } = fakeCdp([controls], (params) => {
+    const { cdp, send, nodes } = await fakeCdp([controls], (params) => {
       const doc = {
         querySelectorAll: (selector: string) =>
           selector === "input,textarea,select" ? elements : [],
@@ -257,9 +285,9 @@ describe("form state identity", () => {
       expect(entries).toHaveLength(250);
       return reply(entries.map(([element, json]) => [element.backendNodeId, JSON.parse(json)]));
     });
-    const captured = await captureViewModel(cdp, 7);
-    expect(captured.nodes.find((n) => n.backendNodeId === 250)?.formValue).toBe("live 250");
-    expect(captured.nodes.find((n) => n.backendNodeId === 251)?.formValue).toBe("old");
+    await enrichFormControlStates(cdp, 7, nodes);
+    expect(nodes[0].find((n) => n.backendNodeId === 250)?.formValue).toBe("live 250");
+    expect(nodes[0].find((n) => n.backendNodeId === 251)?.formValue).toBe("old");
     expect(send.mock.calls.filter(([, method]) => method === "Runtime.evaluate")).toHaveLength(1);
     expect(
       send.mock.calls.filter(([, method]) => method === "Runtime.releaseObjectGroup"),

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

@@ -1,283 +0,0 @@
-import { describe, expect, it, vi } from "vitest";
-import type { CdpRunner } from "../../shared";
-import type { CapturedNode, CapturedViewModel } from "../capture";
-import { captureFrameData } from "../frame-capture";
-
-function ownerNode(backendNodeId: number, x: number): CapturedNode {
-  return {
-    backendNodeId,
-    parentBackendNodeId: 1,
-    frameId: "main",
-    ownerFrameBackendNodeId: null,
-    tag: "iframe",
-    attrs: {},
-    rect: { x, y: 100, w: 300, h: 200 },
-    localRect: { x, y: 100, w: 300, h: 200 },
-    paintOrder: 1,
-    position: "static",
-    pointerEvents: "auto",
-  };
-}
-
-function childSnapshot(frameId: string, backendNodeId: number) {
-  const strings = [frameId, "body", "button", "static", "auto", "pointer"];
-  return {
-    strings,
-    documents: [
-      {
-        scrollOffsetX: 0,
-        scrollOffsetY: 0,
-        frameId,
-        nodes: {
-          parentIndex: [-1, 0],
-          nodeName: [1, 2],
-          backendNodeId: [backendNodeId - 1, backendNodeId],
-          attributes: [[], []],
-        },
-        layout: {
-          nodeIndex: [0, 1],
-          styles: [
-            [3, 4, 4],
-            [3, 4, 5],
-          ],
-          bounds: [
-            [0, 0, 300, 200],
-            [10, 20, 100, 40],
-          ],
-          paintOrders: [0, 1],
-        },
-      },
-    ],
-  };
-}
-
-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);
-    const captured: CapturedViewModel = {
-      nodes: [leftOwner, rightOwner],
-      viewport: { width: 1000, height: 800 },
-      iframeNodes: new Map(),
-      frameNodes: new Map([["main", [leftOwner, rightOwner]]]),
-      frameOwnerBackendNodeIds: new Map(),
-      rootFrameId: "main",
-      excludedBackendNodeIds: new Set(),
-    };
-    const sendToTarget = vi.fn(async (target, method) => {
-      if (method === "Page.getLayoutMetrics") {
-        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") {
-        return target.sessionId === "left-session"
-          ? childSnapshot("left", 101)
-          : childSnapshot("right", 201);
-      }
-      if (method === "Accessibility.getFullAXTree") return { nodes: [] };
-      throw new Error(`unexpected ${method}`);
-    });
-    const cdp: CdpRunner = {
-      send: vi.fn(async (_tabId, method, params) => {
-        if (method === "Accessibility.enable") return {};
-        if (method === "Accessibility.getFullAXTree") return { nodes: [] };
-        if (method === "DOM.getBoxModel") {
-          const backendNodeId = (params as { backendNodeId?: number })?.backendNodeId;
-          const x = backendNodeId === 10 ? 50 : 500;
-          return { model: { content: [x, 100, x + 300, 100, x + 300, 300, x, 300] } };
-        }
-        if (method === "Page.getLayoutMetrics") {
-          return {
-            visualViewport: { clientWidth: 1000 },
-            cssVisualViewport: { clientWidth: 1000 },
-            cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 },
-          };
-        }
-        throw new Error(`unexpected root ${method}`);
-      }) as CdpRunner["send"],
-      sendToTarget: sendToTarget as unknown as NonNullable<CdpRunner["sendToTarget"]>,
-      getFrameGraph: vi.fn(async () => ({
-        rootFrameId: "main",
-        frames: [
-          { frameId: "main", target: { tabId: 4 } },
-          {
-            frameId: "left",
-            parentFrameId: "main",
-            ownerBackendNodeId: 10,
-            target: { tabId: 4, sessionId: "left-session" },
-          },
-          {
-            frameId: "right",
-            parentFrameId: "main",
-            ownerBackendNodeId: 20,
-            target: { tabId: 4, sessionId: "right-session" },
-          },
-        ],
-      })),
-    };
-
-    const trees = await captureFrameData(cdp, 4, captured);
-
-    expect(trees.map((tree) => tree.frameId)).toEqual(["main", "left", "right"]);
-    expect(
-      captured.frameNodes?.get("left")?.find((node) => node.backendNodeId === 101)?.rect,
-    ).toEqual({ x: 60, y: 120, w: 100, h: 40 });
-    expect(
-      captured.frameNodes?.get("right")?.find((node) => node.backendNodeId === 201)?.rect,
-    ).toEqual({ x: 510, y: 120, w: 100, h: 40 });
-    expect(captured.frameOwnerBackendNodeIds).toEqual(
-      new Map([
-        ["left", 10],
-        ["right", 20],
-      ]),
-    );
-    expect(captured.frameParentIds).toEqual(
-      new Map([
-        ["left", "main"],
-        ["right", "main"],
-      ]),
-    );
-  });
-
-  it("keeps OOPIF semantics when viewport projection is unavailable", async () => {
-    const owner = { ...ownerNode(10, 50), rect: null, localRect: null };
-    const captured: CapturedViewModel = {
-      nodes: [owner],
-      viewport: { width: 1000, height: 800 },
-      iframeNodes: new Map(),
-      frameNodes: new Map([["main", [owner]]]),
-      rootFrameId: "main",
-      excludedBackendNodeIds: new Set(),
-    };
-    const cdp: CdpRunner = {
-      send: vi.fn(async (_tabId, method) => {
-        if (method === "Accessibility.enable") return {};
-        if (method === "Accessibility.getFullAXTree") return { nodes: [] };
-        if (method === "DOM.getBoxModel") throw new Error("owner geometry unavailable");
-        if (method === "Page.getLayoutMetrics") {
-          return {
-            visualViewport: { clientWidth: 1000 },
-            cssVisualViewport: { clientWidth: 1000 },
-            cssLayoutViewport: { clientWidth: 1000, clientHeight: 800 },
-          };
-        }
-        throw new Error(`unexpected root ${method}`);
-      }) as CdpRunner["send"],
-      sendToTarget: vi.fn(async (_target, method) => {
-        if (method === "Page.getLayoutMetrics") throw new Error("viewport unavailable");
-        if (method === "DOMSnapshot.enable" || method === "Accessibility.enable") return {};
-        if (method === "DOMSnapshot.captureSnapshot") return childSnapshot("child", 101);
-        if (method === "Accessibility.getFullAXTree") {
-          return {
-            nodes: [
-              {
-                nodeId: "button",
-                backendDOMNodeId: 101,
-                role: { type: "role", value: "button" },
-                name: { type: "computedString", value: "Continue" },
-              },
-            ],
-          };
-        }
-        throw new Error(`unexpected ${method}`);
-      }) as unknown 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" },
-          },
-        ],
-      })),
-    };
-
-    const documents = await captureFrameData(cdp, 4, captured);
-    const childDocument = documents.find((document) => document.frameId === "child");
-
-    expect(childDocument?.axNodes).toEqual([
-      expect.objectContaining({ backendDOMNodeId: 101, frameId: "child" }),
-    ]);
-    expect(childDocument?.domNodes.find((node) => node.backendNodeId === 101)).toEqual(
-      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/__tests__/frame-document.test.ts

@@ -1,7 +1,12 @@
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
 import type { CdpFrameGraph } from "@/browser-driver/frame-graph";
-import type { CapturedNode, CapturedViewModel } from "../capture";
-import { buildFrameDocuments, type FrameAxBatch, type FrameOwnedAxNode } from "../frame-document";
+import type { CapturedNode } from "../capture";
+import {
+  buildFrameDocuments,
+  type FrameAxBatch,
+  type FrameDomInput,
+  type FrameOwnedAxNode,
+} from "../frame-document";
 
 function domNode(frameId: string, backendNodeId: number): CapturedNode {
   return {
@@ -17,19 +22,16 @@ function domNode(frameId: string, backendNodeId: number): CapturedNode {
   };
 }
 
-function captured(frameNodes: Map<string, CapturedNode[]>): CapturedViewModel {
+function captured(frameNodes: Map<string, CapturedNode[]>): FrameDomInput {
   return {
     nodes: frameNodes.get("main") ?? [],
-    viewport: { width: 800, height: 600 },
-    iframeNodes: new Map(),
     frameNodes,
     rootFrameId: "main",
-    excludedBackendNodeIds: new Set(),
   };
 }
 
 describe("buildFrameDocuments", () => {
-  it("partitions mixed AX results by node ownership and cuts cross-frame parent edges", () => {
+  it("partitions mixed AX results by node ownership and cuts cross-frame parent edges", async () => {
     const graph: CdpFrameGraph = {
       rootFrameId: "main",
       frames: [
@@ -54,7 +56,7 @@ describe("buildFrameDocuments", () => {
       },
     ];
 
-    const documents = buildFrameDocuments(
+    const documents = await buildFrameDocuments(
       graph,
       batches,
       captured(
@@ -72,7 +74,7 @@ describe("buildFrameDocuments", () => {
     expect(childNodes.find((node) => node.nodeId === "virtual")?.frameId).toBe("child");
   });
 
-  it("deduplicates overlapping same-target AX results using the strongest ownership", () => {
+  it("deduplicates overlapping same-target AX results using the strongest ownership", async () => {
     const graph: CdpFrameGraph = {
       rootFrameId: "main",
       frames: [
@@ -92,7 +94,7 @@ describe("buildFrameDocuments", () => {
       },
     ];
 
-    const documents = buildFrameDocuments(
+    const documents = await buildFrameDocuments(
       graph,
       batches,
       captured(
@@ -107,7 +109,7 @@ describe("buildFrameDocuments", () => {
     expect(documents.find((document) => document.frameId === "child")?.axNodes).toHaveLength(1);
   });
 
-  it("uses target-scoped backend ownership when OOPIF backend ids collide", () => {
+  it("uses target-scoped backend ownership when OOPIF backend ids collide", async () => {
     const graph: CdpFrameGraph = {
       rootFrameId: "main",
       frames: [
@@ -129,7 +131,7 @@ describe("buildFrameDocuments", () => {
       nodes: [{ nodeId: `${frame.frameId}-node`, backendDOMNodeId: 7 }],
     }));
 
-    const documents = buildFrameDocuments(
+    const documents = await buildFrameDocuments(
       graph,
       batches,
       captured(
@@ -149,7 +151,7 @@ describe("buildFrameDocuments", () => {
     );
   });
 
-  it("uses captured frame parent identity instead of guessing from backend ids", () => {
+  it("uses captured frame parent identity instead of guessing from backend ids", async () => {
     const frameNodes = new Map([
       ["main", [domNode("main", 1)]],
       ["left", [domNode("left", 7)]],
@@ -157,18 +159,51 @@ describe("buildFrameDocuments", () => {
       ["child", [domNode("child", 9)]],
     ]);
     const capture = captured(frameNodes);
-    capture.frameOwnerBackendNodeIds = new Map([["child", 7]]);
-    capture.frameParentIds = new Map([["child", "left"]]);
     const frames = ["main", "left", "right", "child"].map((frameId) => ({
-      frame: { frameId, target: { tabId: 4 } },
+      frame: {
+        frameId,
+        target: { tabId: 4 },
+        ...(frameId === "child" ? { parentFrameId: "left", ownerBackendNodeId: 7 } : {}),
+      },
       nodes: [],
     }));
 
-    const documents = buildFrameDocuments(null, frames, capture);
+    const documents = await buildFrameDocuments(null, frames, capture);
 
     expect(documents.find((document) => document.frameId === "child")).toMatchObject({
       parentFrameId: "left",
       ownerBackendNodeId: 7,
     });
   });
+  it("rejects explicit AX frame ownership in a different target", async () => {
+    const frames = [
+      { frameId: "main", target: { tabId: 4 } },
+      { frameId: "remote", target: { tabId: 4, sessionId: "remote" } },
+    ];
+    const unresolved = vi.fn();
+    const documents = await buildFrameDocuments(
+      { rootFrameId: "main", frames },
+      [{ frame: frames[0], nodes: [{ nodeId: "wrong", frameId: "remote" }] }],
+      captured(new Map()),
+      undefined,
+      unresolved,
+    );
+    expect(documents.every((doc) => doc.axNodes.length === 0)).toBe(true);
+    expect(unresolved).toHaveBeenCalledOnce();
+  });
+
+  it("resolves a reverse-ordered deep AX parent chain without recursion", async () => {
+    const frame = { frameId: "main", target: { tabId: 4 } };
+    const nodes: FrameOwnedAxNode[] = Array.from({ length: 10000 }, (_, i) => ({
+      nodeId: String(i),
+      ...(i ? { parentId: String(i - 1) } : { frameId: "main" }),
+    })).reverse();
+    const documents = await buildFrameDocuments(
+      { rootFrameId: "main", frames: [frame] },
+      [{ frame, nodes }],
+      captured(new Map()),
+    );
+    expect(documents[0].axNodes).toHaveLength(10000);
+    expect(documents[0].axNodes[0].frameId).toBe("main");
+  });
 });

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

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

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

@@ -0,0 +1,413 @@
+import {
+  type CdpFrame,
+  type CdpFrameGraph,
+  type CdpTarget,
+  cdpTargetKey,
+} from "@/browser-driver/frame-graph";
+import { cssViewport, GeometryContext } from "../geometry/frame-context";
+import { type CdpRunner, cdpRunnerForTarget } from "../shared";
+import { collectOverlayExcludedBackendIds } from "./capture";
+import {
+  isAbortError as isCaptureAbort,
+  throwIfAborted as throwCaptureAborted,
+} from "./capture-abort";
+import { verifyDocumentIdentity } from "./document-identity";
+import type { CapturedSceneInput, DocumentIdentity } from "./facts";
+import { buildDocumentIndex, type CaptureIssue, type ObservationFacts } from "./facts";
+import { enrichFormControlStates } from "./form-capture";
+import {
+  buildFrameDocuments,
+  type FrameAxBatch,
+  type FrameDocument,
+  type FrameOwnedAxNode,
+} from "./frame-document";
+import { type NormalizedFrameDocument, normalizeSnapshot } from "./normalize";
+import { describeSnapshotFrames, REQUESTED_STYLES, type SnapshotReply } from "./snapshot";
+
+interface TargetBatch<T extends FrameOwnedAxNode> {
+  target: CdpTarget;
+  frames: CdpFrame[];
+  snapshotAttachmentId?: string;
+  documents: NormalizedFrameDocument[];
+  ax: FrameAxBatch<T>[];
+  fallbackExcluded: Set<number>;
+  snapshotFrameIds?: Set<string>;
+  rootFrameId?: string;
+}
+
+/** A fixed worker pool scoped to one capture; each worker issues at most one
+ * collection request at a time. Geometry has its own measurement-phase bound. */
+async function collectTasks<T>(
+  items: readonly T[],
+  collect: (item: T) => Promise<void>,
+  signal?: AbortSignal,
+): Promise<void> {
+  let cursor = 0;
+  let failed = false;
+  let failure: unknown;
+  await Promise.all(
+    Array.from({ length: Math.min(4, items.length) }, async () => {
+      try {
+        while (cursor < items.length && !failed && !signal?.aborted) {
+          const item = items[cursor++];
+          await collect(item);
+        }
+      } catch (error) {
+        if (!failed) failure = error;
+        failed = true;
+      }
+    }),
+  );
+  // A worker's rejection must not let the capture outlive its own task scope.
+  // In-flight reads and their finally blocks settle before cancellation/failure.
+  throwCaptureAborted(signal);
+  if (failed) throw failure;
+}
+
+export async function captureObservationFacts<T extends FrameOwnedAxNode>(
+  cdp: CdpRunner,
+  tabId: number,
+  signal?: AbortSignal,
+  pageUrl?: string,
+): Promise<ObservationFacts<T>> {
+  const startedAt = Date.now();
+  throwCaptureAborted(signal);
+  let graph: CdpFrameGraph | undefined;
+  try {
+    graph = await cdp.getFrameGraph?.(tabId);
+  } catch (error) {
+    if (isCaptureAbort(error)) throw error;
+  }
+  throwCaptureAborted(signal);
+  const geometry = new GeometryContext(cdp, tabId, graph, signal);
+  const issues: CaptureIssue[] = [];
+  const graphFrames = new Map(graph?.frames.map((frame) => [frame.frameId, frame]) ?? []);
+  const groups = new Map<string, TargetBatch<T>>();
+  for (const frame of graph?.frames ?? []) {
+    const key = cdpTargetKey(frame.target);
+    let group = groups.get(key);
+    if (!group) {
+      group = {
+        target: frame.target,
+        frames: [],
+        documents: [],
+        ax: [],
+        fallbackExcluded: new Set(),
+      };
+      groups.set(key, group);
+    }
+    group.frames.push(
+      !frame.target.sessionId && frame.frameId === graph?.rootFrameId && !frame.url && pageUrl
+        ? { ...frame, url: pageUrl }
+        : frame,
+    );
+  }
+  if (!groups.has(cdpTargetKey({ tabId })))
+    groups.set(cdpTargetKey({ tabId }), {
+      target: { tabId },
+      frames: [],
+      documents: [],
+      ax: [],
+      fallbackExcluded: new Set(),
+    });
+  const batches = [...groups.values()];
+  const unavailable = (batch: TargetBatch<T>, stage: CaptureIssue["stage"], frameId?: string) =>
+    issues.push({ target: batch.target, frameId, stage, reason: "capture-unavailable" });
+  let firstFailure: unknown;
+  const axReady = new Set<TargetBatch<T>>();
+  await collectTasks(
+    batches,
+    async (batch) => {
+      const scoped = cdpRunnerForTarget(cdp, batch.target);
+      try {
+        throwCaptureAborted(signal);
+        await scoped.send(tabId, "DOMSnapshot.enable", {});
+        throwCaptureAborted(signal);
+        batch.snapshotAttachmentId = cdp.getAttachmentId?.(tabId);
+        const snapshot = await scoped.send<SnapshotReply>(tabId, "DOMSnapshot.captureSnapshot", {
+          computedStyles: REQUESTED_STYLES,
+          includePaintOrder: true,
+          includeDOMRects: true,
+        });
+        throwCaptureAborted(signal);
+        const observed = describeSnapshotFrames(snapshot, batch.target, graphFrames, pageUrl);
+        batch.snapshotFrameIds = observed.ids;
+        batch.rootFrameId = observed.rootFrameId;
+        // Keep graph-only frames for AX fallback, never in preference to observed membership.
+        batch.frames = [
+          ...observed.frames,
+          ...batch.frames.filter((frame) => !observed.ids.has(frame.frameId)),
+        ];
+        batch.documents = await normalizeSnapshot(
+          snapshot,
+          batch.target,
+          batch.frames.filter((frame) => observed.ids.has(frame.frameId)),
+          geometry,
+          issues,
+          signal,
+          observed.rootFrameId,
+        );
+        const formsAvailable = await enrichFormControlStates(
+          scoped,
+          tabId,
+          batch.documents.map((doc) => doc.nodes),
+          signal,
+        );
+        throwCaptureAborted(signal);
+        if (!formsAvailable) unavailable(batch, "forms");
+        const present = new Set(batch.documents.map((doc) => doc.frame.frameId));
+        for (const frame of batch.frames)
+          if (!present.has(frame.frameId)) unavailable(batch, "dom", frame.frameId);
+      } catch (error) {
+        throwCaptureAborted(signal);
+        if (isCaptureAbort(error)) throw error;
+        firstFailure ??= error;
+        unavailable(batch, "dom");
+        batch.fallbackExcluded = await collectOverlayExcludedBackendIds(scoped, tabId, signal);
+      }
+      if (!batch.frames.length && !graph)
+        batch.frames = [
+          {
+            frameId: "root",
+            target: batch.target,
+            ...(!batch.target.sessionId && pageUrl ? { url: pageUrl } : {}),
+          },
+        ];
+      try {
+        throwCaptureAborted(signal);
+        await scoped.send(tabId, "Accessibility.enable", {});
+      } catch (error) {
+        throwCaptureAborted(signal);
+        if (isCaptureAbort(error)) throw error;
+        firstFailure ??= error;
+        unavailable(batch, "ax");
+        return;
+      }
+      axReady.add(batch);
+    },
+    signal,
+  );
+
+  // Schedule AX by frame across all ready targets, rather than nesting pools.
+  // Keep result slots in source order even when CDP replies arrive out of order.
+  const axTasks: { batch: TargetBatch<T>; frame: CdpFrame; result?: FrameAxBatch<T> }[] =
+    batches.flatMap((batch) =>
+      axReady.has(batch) ? batch.frames.map((frame) => ({ batch, frame })) : [],
+    );
+  await collectTasks(
+    axTasks,
+    async (task) => {
+      const { batch, frame } = task;
+      try {
+        throwCaptureAborted(signal);
+        const result = await cdpRunnerForTarget(cdp, batch.target).send<{ nodes?: T[] }>(
+          tabId,
+          "Accessibility.getFullAXTree",
+          frame.frameId === "root" ? {} : { frameId: frame.frameId },
+        );
+        throwCaptureAborted(signal);
+        task.result = { frame, nodes: result.nodes ?? [] };
+      } catch (error) {
+        throwCaptureAborted(signal);
+        if (isCaptureAbort(error)) throw error;
+        firstFailure ??= error;
+        unavailable(batch, "ax", frame.frameId);
+      }
+    },
+    signal,
+  );
+  for (const task of axTasks) if (task.result) task.batch.ax.push(task.result);
+
+  let viewport = { width: 0, height: 0 };
+  try {
+    const measured = cssViewport(await geometry.layoutMetrics({ tabId }));
+    viewport = { width: measured.width, height: measured.height };
+  } catch (error) {
+    if (isCaptureAbort(error)) throw error;
+  }
+
+  // A snapshot claim outranks an old graph hint. Conflicting actual claims
+  // cannot be resolved by completion order or by overwriting a frameId map.
+  const claims = new Map<string, string>();
+  const invalid = new Set<string>();
+  for (const batch of batches) {
+    const targetKey = cdpTargetKey(batch.target);
+    for (const id of batch.snapshotFrameIds ?? []) {
+      const previous = claims.get(id);
+      if (previous !== undefined && previous !== targetKey) invalid.add(id);
+      claims.set(id, targetKey);
+    }
+    const accepted = new Set(batch.frames.map((frame) => frame.frameId));
+    for (const id of batch.snapshotFrameIds ?? []) if (!accepted.has(id)) invalid.add(id);
+  }
+  const currentFrames = batches.flatMap((batch) =>
+    batch.frames.filter(
+      (frame) =>
+        !claims.has(frame.frameId) || claims.get(frame.frameId) === cdpTargetKey(batch.target),
+    ),
+  );
+  const rootBatch = batches.find((batch) => !batch.target.sessionId);
+  const rootFrameId =
+    rootBatch?.rootFrameId ?? graph?.rootFrameId ?? rootBatch?.frames[0]?.frameId ?? "root";
+  const ownershipInvalid = new Set(invalid);
+  const identities = new Map<string, DocumentIdentity>();
+  const selected = new Map(currentFrames.map((frame) => [frame.frameId, frame]));
+  const checks = batches.flatMap((batch) => {
+    const docs = new Map(batch.documents.map((doc) => [doc.frame.frameId, doc]));
+    return batch.frames
+      .filter(
+        (frame) =>
+          !invalid.has(frame.frameId) &&
+          cdpTargetKey(selected.get(frame.frameId)!.target) === cdpTargetKey(batch.target),
+      )
+      .map((frame) => ({ batch, frame, doc: docs.get(frame.frameId) }));
+  });
+  await collectTasks(
+    checks,
+    async ({ batch, frame, doc }) => {
+      throwCaptureAborted(signal);
+      if (!batch.snapshotAttachmentId || doc?.documentElementBackendNodeId === undefined) {
+        issues.push({
+          target: frame.target,
+          frameId: frame.frameId,
+          stage: "identity",
+          reason: "identity-unverified",
+        });
+        return;
+      }
+      const identity: DocumentIdentity = {
+        attachmentId: batch.snapshotAttachmentId,
+        target: frame.target,
+        frameId: frame.frameId,
+        documentElementBackendNodeId: doc.documentElementBackendNodeId,
+      };
+      const verified = await verifyDocumentIdentity(cdp, identity, signal);
+      const status = cdp.getAttachmentId?.(tabId) === identity.attachmentId ? verified : "changed";
+      if (status === "current") identities.set(frame.frameId, identity);
+      else {
+        invalid.add(frame.frameId);
+        issues.push({
+          target: frame.target,
+          frameId: frame.frameId,
+          stage: "identity",
+          reason: status === "changed" ? "document-changed" : "identity-unavailable",
+        });
+      }
+    },
+    signal,
+  );
+  const children = new Map<string, string[]>();
+  for (const frame of currentFrames) {
+    if (!frame.parentFrameId) continue;
+    const siblings = children.get(frame.parentFrameId);
+    if (siblings) siblings.push(frame.frameId);
+    else children.set(frame.parentFrameId, [frame.frameId]);
+  }
+  const blocked = [...invalid];
+  for (let i = 0; i < blocked.length; i++) {
+    for (const child of children.get(blocked[i]) ?? []) {
+      if (!invalid.has(child)) {
+        invalid.add(child);
+        blocked.push(child);
+      }
+    }
+  }
+  for (const frame of currentFrames) {
+    if (ownershipInvalid.has(frame.frameId))
+      issues.push({
+        target: frame.target,
+        frameId: frame.frameId,
+        stage: "ownership",
+        reason: "frame-ownership-unresolved",
+      });
+  }
+  if (invalid.has(rootFrameId))
+    throw new Error(
+      ownershipInvalid.has(rootFrameId)
+        ? "observation root document ownership is ambiguous"
+        : "observation document identity changed or could not be verified; observe again",
+    );
+  const frames = currentFrames.filter((frame) => !invalid.has(frame.frameId));
+  const frameById = new Map(frames.map((frame) => [frame.frameId, frame]));
+  const belongs = (frame: CdpFrame) => {
+    const current = frameById.get(frame.frameId);
+    return current && cdpTargetKey(current.target) === cdpTargetKey(frame.target);
+  };
+  const decoded = new Map(
+    batches
+      .flatMap((batch) => batch.documents)
+      .filter((doc) => belongs(doc.frame))
+      .map((doc) => [doc.frame.frameId, doc]),
+  );
+  const ax = batches.flatMap((batch) => batch.ax).filter((batch) => belongs(batch.frame));
+  const documents = await buildFrameDocuments(
+    { rootFrameId, frames },
+    ax,
+    {
+      nodes: [],
+      rootFrameId,
+      frameNodes: new Map([...decoded].map(([id, doc]) => [id, doc.nodes])),
+      frameExcludedBackendNodeIds: new Map(
+        [...decoded].map(([id, doc]) => [id, doc.index.excludedBackendNodeIds]),
+      ),
+    },
+    signal,
+    (frame) =>
+      issues.push({
+        target: frame.target,
+        frameId: frame.frameId,
+        stage: "ownership",
+        reason: "frame-ownership-unresolved",
+      }),
+  );
+  const facts: ObservationFacts<T>["documents"][number][] = [];
+  for (const document of documents) {
+    const doc = decoded.get(document.frameId);
+    const index = doc?.index ?? (await buildDocumentIndex([], signal));
+    const fallback = groups.get(cdpTargetKey(document.target))?.fallbackExcluded;
+    const {
+      domNodes,
+      axNodes,
+      contextScopeId: _scope,
+      excludedBackendNodeIds: _excluded,
+      ...frame
+    } = document;
+    facts.push({
+      frame,
+      identity: identities.get(document.frameId),
+      index: fallback?.size ? { ...index, excludedBackendNodeIds: fallback } : index,
+      domNodes,
+      axNodes,
+    });
+  }
+  throwCaptureAborted(signal);
+  if (firstFailure && facts.every((doc) => !doc.domNodes.length && !doc.axNodes.length))
+    throw firstFailure;
+  return { rootFrameId, viewport, documents: facts, issues, startedAt, finishedAt: Date.now() };
+}
+
+/** Existing semantic consumers get a narrow view; no raw snapshot
+ * data can leak through recording's allowlisted output DTO. */
+export function semanticCapture<T extends FrameOwnedAxNode>(
+  facts: ObservationFacts<T>,
+): { captured: CapturedSceneInput; documents: FrameDocument<T>[] } {
+  const documents = facts.documents.map((doc) => ({
+    ...doc.frame,
+    contextScopeId: doc.frame.frameId,
+    domNodes: doc.domNodes.filter(
+      (node) => !doc.index.excludedBackendNodeIds.has(node.backendNodeId),
+    ),
+    axNodes: doc.axNodes,
+    excludedBackendNodeIds: doc.index.excludedBackendNodeIds,
+  }));
+  const root = documents.find((doc) => doc.frameId === facts.rootFrameId);
+  return {
+    documents,
+    captured: {
+      nodes: root?.domNodes ?? [],
+      viewport: facts.viewport,
+      rootFrameId: facts.rootFrameId,
+      excludedBackendNodeIds: root?.excludedBackendNodeIds ?? new Set(),
+    },
+  };
+}

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

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

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

@@ -1,339 +1,22 @@
-// CDP capture adapter: DOMSnapshot.captureSnapshot + Page.getLayoutMetrics
-// → CapturedNode[] + Viewport. This is the ONLY VOM module that touches
-// raw CDP. The captureSnapshot reply is columnar (parallel arrays + a
-// shared string table); requested computed styles are decoded through
-// 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";
+// Browser-side hover probes and overlay exclusion fallback. Static collection
+// lives in capture-coordinator; snapshot decoding has no browser dependency.
 import { evaluateHoverTrigger } from "@/lib/hover-trigger-policy";
-import { isOverlayHostNode, OVERLAY_HOST_SELECTOR } from "../../lib/overlay-bridge";
-import {
-  type FrameProjectionIssue,
-  type FrameProjectionState,
-  projectSnapshotRect,
-  type SnapshotCoordinates,
-  snapshotCoordinates,
-  snapshotViewportRect,
-} from "../geometry/coordinate-types";
-import {
-  GeometryContext,
-  type LayoutMetrics,
-  snapshotLayoutScale,
-} from "../geometry/frame-context";
+import { OVERLAY_HOST_SELECTOR } from "../../lib/overlay-bridge";
 import type { CdpRunner } from "../shared";
+import type { CapturedNode } from "./capture-types";
+import type { CapturedSurfaceProbe } from "./facts";
+
+export type {
+  CapturedNode,
+  CapturedSurfaceProbe,
+} from "./facts";
+
+import { isAbortError, throwIfAborted } from "./capture-abort";
 import { clearHover, ProbeBudget, waitForHover } from "./hover-perception";
 
-const REQUESTED_STYLES = ["position", "pointer-events", "cursor", "visibility", "opacity"] as const;
-const STYLE_COL = Object.fromEntries(
-  REQUESTED_STYLES.map((name, index) => [name, index]),
-) as Record<(typeof REQUESTED_STYLES)[number], number>;
-
-export interface CapturedNode {
-  backendNodeId: number;
-  parentBackendNodeId: number | null;
-  frameId?: string;
-  /** Owning iframe backend node id; `null` for the top-level document. */
-  ownerFrameBackendNodeId?: number | null;
-  tag: string;
-  attrs: Record<string, string>;
-  /** Top-level viewport-relative CSS px, clipped to the owning frame viewport. */
-  rect: Rect | null;
-  /** Frame-local viewport-relative CSS px before top-level projection. */
-  localRect?: Rect | null;
-  paintOrder: number;
-  position: string;
-  pointerEvents: string;
-  /**
-   * computed `cursor`. `cursor: pointer` is the strongest CDP-free signal
-   * that a non-semantic element (a `<div>`/`<span>` with a click handler)
-   * is actually an interactive control — used by the adapter to surface
-   * custom buttons/checkboxes the AX tree drops as `generic`. Optional like
-   * `textContent`: the live parser always sets it, hand-built fixtures may not.
-   */
-  cursor?: string;
-  /**
-   * Whether the live DOM snapshot provides a painted, non-hidden box for this
-   * node. Semantic resolution uses this only for DOM fallback nodes; AX-backed
-   * nodes remain authoritative even when they are outside the viewport.
-   */
-  rendered?: boolean;
-  textContent?: string;
-  formState?: "empty" | "filled" | "default";
-  formValue?: string;
-  formDefaultValue?: string;
-  formPlaceholder?: string;
-}
-
-export type CapturedIframeNodes = Map<number, CapturedNode[]>;
-
-export interface CapturedSurfaceProbe {
-  triggerBackendNodeId: number;
-  triggerPoint?: { x: number; y: number };
-  triggerAction: "hover" | "focus" | string;
-  subItems: string[];
-  confidence?: "high" | "medium" | "low";
-}
-
-export interface CapturedViewModel {
-  nodes: CapturedNode[];
-  viewport: Viewport;
-  iframeNodes: CapturedIframeNodes;
-  frameNodes?: Map<string, CapturedNode[]>;
-  frameOwnerBackendNodeIds?: Map<string, number>;
-  /** 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 {
-  const error = new Error("observation aborted");
-  error.name = "AbortError";
-  return error;
-}
-
-function isAbortError(error: unknown): boolean {
-  return (
-    typeof error === "object" &&
-    error !== null &&
-    (error as { name?: string }).name === "AbortError"
-  );
-}
-
-function throwIfAborted(signal: AbortSignal | undefined): void {
-  if (signal?.aborted) throw captureAbortError();
-}
-
-/** Sparse array format Chrome uses for infrequently-set per-node fields. */
-interface SparseArray {
-  index: number[];
-  value: number[];
-}
-
-interface RareBooleanData {
-  index: number[];
-}
-
-interface SnapshotDocument {
-  frameId?: string | number;
-  scrollOffsetX?: number;
-  scrollOffsetY?: number;
-  nodes?: {
-    parentIndex?: number[];
-    nodeName?: number[];
-    backendNodeId?: number[];
-    attributes?: number[][];
-    /**
-     * Per-node text value (index into strings), set for `#text` / CDATA nodes.
-     * Element nodes carry -1. Same length as `backendNodeId`.
-     */
-    nodeValue?: number[];
-    /** Maps node array index → index into `documents[]` for frame content. */
-    contentDocumentIndex?: SparseArray;
-    inputValue?: SparseArray;
-    textValue?: SparseArray;
-    inputChecked?: RareBooleanData;
-    optionSelected?: RareBooleanData;
-  };
-  layout?: {
-    nodeIndex?: number[];
-    styles?: number[][];
-    bounds?: number[][];
-    paintOrders?: number[];
-  };
-}
-
-function snapshotFrameId(document: SnapshotDocument, strings: string[]): string | undefined {
-  if (typeof document.frameId === "string") return document.frameId || undefined;
-  if (typeof document.frameId === "number") return str(strings, document.frameId) || undefined;
-  return undefined;
-}
-
-interface SnapshotReply {
-  strings?: string[];
-  documents?: SnapshotDocument[];
-}
-
-function isFormControlTag(tag: string): boolean {
-  return tag === "input" || tag === "textarea" || tag === "select";
-}
-
-function isSensitiveFormControl(node: Pick<CapturedNode, "tag" | "attrs">): boolean {
-  return node.tag === "input" && (node.attrs.type ?? "").toLowerCase() === "password";
-}
-
-function snapshotFormState(
-  value: string | undefined,
-  defaultValue: string,
-  hasDefaultValue: boolean,
-  sensitive: boolean,
-): CapturedNode["formState"] {
-  if (sensitive) {
-    if (value === undefined && !hasDefaultValue) return undefined;
-    return (value ?? defaultValue) === "" ? "empty" : "filled";
-  }
-  if (value === undefined) return undefined;
-  if (value === "") return "empty";
-  return value === defaultValue ? "default" : "filled";
-}
-
-const MAX_FORM_ENRICH_CONTROLS = 250;
-
-interface CapturedFormState {
-  value?: string;
-  defaultValue?: string;
-  placeholder?: string;
-  state?: "empty" | "filled" | "default";
-  sensitive?: boolean;
-}
-
-interface DeepSerializedValue {
-  type: string;
-  value?: unknown;
-}
-
-function formStateBatchExpression(maxControls: number): string {
-  return `(() => {
-    const maxControls = ${JSON.stringify(maxControls)};
-    let remaining = maxControls;
-    const controlSelector = "input,textarea,select";
-    const controlState = (el) => {
-      const tag = el.tagName.toLowerCase();
-      const type = tag === "input" ? String(el.type || "text").toLowerCase() : tag;
-      const sensitive = type === "password" || type === "credit-card";
-      const rawValue = typeof el.value === "string" ? el.value : "";
-      const defaultValue = typeof el.defaultValue === "string" ? el.defaultValue : "";
-      const placeholder = typeof el.placeholder === "string" ? el.placeholder : "";
-      const state = rawValue === "" ? "empty" : rawValue === defaultValue ? "default" : "filled";
-      return {
-        state,
-        sensitive,
-        placeholder,
-        ...(sensitive ? {} : { value: rawValue, defaultValue }),
-      };
-    };
-    const controls = [];
-    const collect = (doc) => {
-      for (const el of Array.from(doc.querySelectorAll(controlSelector))) {
-        if (remaining <= 0) break;
-        // Deep serialization supplies the node's backend id. Keep the
-        // state as JSON so decoding needs no general-purpose V8 deserializer.
-        controls.push([el, JSON.stringify(controlState(el))]);
-        remaining -= 1;
-      }
-      for (const frame of Array.from(doc.querySelectorAll("iframe"))) {
-        if (remaining <= 0) break;
-        let childDoc = null;
-        try { childDoc = frame.contentDocument; } catch { childDoc = null; }
-        if (childDoc) collect(childDoc);
-      }
-    };
-    collect(document);
-    return controls;
-  })()`;
-}
-
-function formStatesByBackendId(result: RuntimeEvaluateReply): Map<number, CapturedFormState> {
-  const states = new Map<number, CapturedFormState>();
-  const serialized = result.result?.deepSerializedValue;
-  if (serialized?.type !== "array" || !Array.isArray(serialized.value)) return states;
-  for (const entry of serialized.value as DeepSerializedValue[]) {
-    if (entry?.type !== "array" || !Array.isArray(entry.value)) continue;
-    const [element, json] = entry.value as DeepSerializedValue[];
-    if (element?.type !== "node" || json?.type !== "string" || typeof json.value !== "string") {
-      continue;
-    }
-    const backendNodeId = (element.value as { backendNodeId?: number } | undefined)?.backendNodeId;
-    if (typeof backendNodeId !== "number" || !Number.isSafeInteger(backendNodeId)) continue;
-    try {
-      const state = JSON.parse(json.value) as CapturedFormState | null;
-      if (
-        !state ||
-        !["empty", "filled", "default"].includes(state.state ?? "") ||
-        typeof state.sensitive !== "boolean" ||
-        typeof state.placeholder !== "string" ||
-        (!state.sensitive &&
-          (typeof state.value !== "string" || typeof state.defaultValue !== "string"))
-      ) {
-        continue;
-      }
-      states.set(backendNodeId, state);
-    } catch {
-      // A malformed entry must not overwrite the snapshot's own state.
-    }
-  }
-  return states;
-}
-
-function applyFormStates(nodes: CapturedNode[], states: Map<number, CapturedFormState>): void {
-  for (const node of nodes) {
-    if (!isFormControlTag(node.tag)) continue;
-    const state = states.get(node.backendNodeId);
-    if (!state) continue;
-    node.formState = state.state;
-    node.formPlaceholder = state.placeholder ?? "";
-    if (state.sensitive || isSensitiveFormControl(node)) {
-      delete node.formValue;
-      delete node.formDefaultValue;
-      delete node.attrs.value;
-    } else {
-      node.formDefaultValue = state.defaultValue ?? "";
-      if (state.value !== undefined) node.formValue = state.value;
-    }
-  }
-}
-
-async function enrichFormControlStates(
-  cdp: CdpRunner,
-  tabId: number,
-  frameNodeGroups: CapturedNode[][],
-  signal?: AbortSignal,
-): Promise<void> {
-  const hasControls = frameNodeGroups.some((nodes) =>
-    nodes.some((node) => isFormControlTag(node.tag)),
-  );
-  if (!hasControls) return;
-  const objectGroup = `bsk-vom-forms-${crypto.randomUUID()}`;
-  try {
-    throwIfAborted(signal);
-    const result = await cdp.send<RuntimeEvaluateReply>(tabId, "Runtime.evaluate", {
-      expression: formStateBatchExpression(MAX_FORM_ENRICH_CONTROLS),
-      objectGroup,
-      serializationOptions: {
-        serialization: "deep",
-        maxDepth: 3,
-        additionalParameters: { maxNodeDepth: 0, includeShadowTree: "none" },
-      },
-    });
-    throwIfAborted(signal);
-    // Backend ids are scoped to this capture's CDP target. OOPIF targets
-    // use their own captureViewModel call and never share this lookup.
-    const states = formStatesByBackendId(result);
-    for (const nodes of frameNodeGroups) {
-      applyFormStates(nodes, states);
-    }
-  } catch (error) {
-    if (isAbortError(error)) throw error;
-    // Best-effort enrichment. DOMSnapshot/AX data still carries the nodes.
-  } finally {
-    await cdp.send(tabId, "Runtime.releaseObjectGroup", { objectGroup }).catch(() => undefined);
-  }
-}
-
 interface RuntimeEvaluateReply {
   result?: {
     value?: unknown;
-    deepSerializedValue?: DeepSerializedValue;
   };
 }
 
@@ -352,36 +35,6 @@ interface CdpDomNode {
   shadowRoots?: CdpDomNode[];
 }
 
-interface ParseDocumentResult {
-  nodes: CapturedNode[];
-  excludedBackendNodeIds: Set<number>;
-}
-
-interface FrameContext {
-  frameId?: string;
-  ownerFrameBackendNodeId: number | null;
-  projection: FrameProjectionState;
-  target: CdpTarget;
-  coordinates: SnapshotCoordinates | null;
-  layoutUnitsPerCssPixel: number | null;
-}
-
-function str(strings: string[], idx: number | undefined): string {
-  if (idx === undefined || idx < 0) return "";
-  return strings[idx] ?? "";
-}
-
-function sparseIndexMap(sparse: SparseArray | undefined): Map<number, number> {
-  const out = new Map<number, number>();
-  if (!sparse?.index || !sparse.value) return out;
-  for (let i = 0; i < sparse.index.length; i++) {
-    const nodeIndex = sparse.index[i];
-    const docIndex = sparse.value[i];
-    if (nodeIndex !== undefined && docIndex !== undefined) out.set(nodeIndex, docIndex);
-  }
-  return out;
-}
-
 function collectBackendIdsFromDomNode(node: CdpDomNode | undefined, out: Set<number>): void {
   if (!node) return;
   if (typeof node.backendNodeId === "number") {
@@ -790,469 +443,3 @@ export async function collectOverlayExcludedBackendIds(
   }
   return excluded;
 }
-
-/**
- * Parse one DOMSnapshot document into CapturedNode[].
- *
- * @param doc   - the raw DOMSnapshot document object
- * @param strings - the shared string table for the whole snapshot
- * @param context - frame coordinate context; output rects are top viewport-relative
- */
-function parseDocumentNodes(
-  doc: SnapshotDocument,
-  strings: string[],
-  context: FrameContext,
-): ParseDocumentResult {
-  const dn = doc.nodes;
-  const dl = doc.layout;
-  if (!dn?.backendNodeId) {
-    return { nodes: [], excludedBackendNodeIds: new Set() };
-  }
-
-  const count = dn.backendNodeId.length;
-  const layoutByNode = new Map<number, number>();
-  (dl?.nodeIndex ?? []).forEach((nodeIdx, layoutIdx) => layoutByNode.set(nodeIdx, layoutIdx));
-
-  // The agent's own overlay (WXT shadow host, marked with OVERLAY_HOST_MARKER_ATTR)
-  // is injected into the page and its open shadow root
-  // is inlined by DOMSnapshot as descendants of the host. Its fixed
-  // full-viewport click-blocker would otherwise dominate occlusion detection
-  // and hide the real page, so mark the host + its whole subtree excluded.
-  // parentIndex always references an earlier node, so one forward pass suffices.
-  const excluded = new Array<boolean>(count).fill(false);
-  const excludedBackendNodeIds = new Set<number>();
-  for (let n = 0; n < count; n++) {
-    const parentIdx = dn.parentIndex?.[n] ?? -1;
-    const inherited = parentIdx >= 0 && excluded[parentIdx];
-    let isOverlayHost = inherited;
-    if (!isOverlayHost) {
-      const pairs = dn.attributes?.[n] ?? [];
-      const attrNames: string[] = [];
-      for (let a = 0; a + 1 < pairs.length; a += 2) {
-        attrNames.push(str(strings, pairs[a]));
-      }
-      isOverlayHost = isOverlayHostNode(str(strings, dn.nodeName?.[n]), attrNames);
-    }
-    if (!isOverlayHost) continue;
-    excluded[n] = true;
-    const backendNodeId = dn.backendNodeId[n];
-    if (backendNodeId !== undefined) {
-      excludedBackendNodeIds.add(backendNodeId);
-    }
-  }
-
-  const posCol = STYLE_COL.position;
-  const peCol = STYLE_COL["pointer-events"];
-  const cursorCol = STYLE_COL.cursor;
-  const visibilityCol = STYLE_COL.visibility;
-  const opacityCol = STYLE_COL.opacity;
-  const inputValues = sparseIndexMap(dn.inputValue);
-  const textValues = sparseIndexMap(dn.textValue);
-  const checkedInputs = new Set(dn.inputChecked?.index ?? []);
-  const selectedOptions = new Set(dn.optionSelected?.index ?? []);
-
-  // Collect visible text from #text child nodes so element CapturedNodes
-  // carry a textContent value usable as a button/link label fallback.
-  // nodeValue is a parallel array: string index for text nodes, -1 otherwise.
-  const nodeTextContent = new Map<number, string>();
-  if (dn.nodeValue) {
-    for (let n = 0; n < count; n++) {
-      const nvIdx = dn.nodeValue[n] ?? -1;
-      if (nvIdx < 0) continue;
-      const text = str(strings, nvIdx).trim();
-      if (!text) continue;
-      const parentIdx = dn.parentIndex?.[n] ?? -1;
-      if (parentIdx >= 0) {
-        const existing = nodeTextContent.get(parentIdx);
-        nodeTextContent.set(parentIdx, existing ? `${existing} ${text}` : text);
-      }
-    }
-  }
-
-  // Build CapturedNodes.
-  const nodes: CapturedNode[] = [];
-  for (let n = 0; n < count; n++) {
-    if (excluded[n]) continue;
-    const backendNodeId = dn.backendNodeId[n];
-    const parentIdx = dn.parentIndex?.[n] ?? -1;
-    const parentBackendNodeId = parentIdx >= 0 ? (dn.backendNodeId[parentIdx] ?? null) : null;
-    const tag = str(strings, dn.nodeName?.[n]).toLowerCase();
-
-    const attrs: Record<string, string> = {};
-    const pairs = dn.attributes?.[n] ?? [];
-    for (let a = 0; a + 1 < pairs.length; a += 2) {
-      attrs[str(strings, pairs[a]).toLowerCase()] = str(strings, pairs[a + 1]);
-    }
-
-    let rect: Rect | null = null;
-    let localRect: Rect | null = null;
-    let paintOrder = 0;
-    let position = "static";
-    let pointerEvents = "auto";
-    let cursor = "auto";
-    let rendered = false;
-    const li = layoutByNode.get(n);
-    if (li !== undefined) {
-      const b = dl?.bounds?.[li];
-      if (b && b.length >= 4 && b[2] > 0 && b[3] > 0) {
-        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;
-      const styleRow = dl?.styles?.[li] ?? [];
-      position = str(strings, styleRow[posCol]) || "static";
-      pointerEvents = str(strings, styleRow[peCol]) || "auto";
-      cursor = str(strings, styleRow[cursorCol]) || "auto";
-      const visibility = str(strings, styleRow[visibilityCol]) || "visible";
-      const opacity = str(strings, styleRow[opacityCol]) || "1";
-      rendered =
-        !!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;
-    }
-
-    // Skip non-element nodes (#text, #cdata-section, etc.) — they carry no
-    // geometry and are never queried by callers.
-    if (tag.startsWith("#")) continue;
-
-    const textContent = nodeTextContent.get(n);
-
-    const rawFormValueIndex = tag === "textarea" ? textValues.get(n) : inputValues.get(n);
-    const rawFormValue =
-      rawFormValueIndex !== undefined ? str(strings, rawFormValueIndex) : undefined;
-    const sensitive = isSensitiveFormControl({ tag, attrs });
-    const formDefaultValue = attrs.value ?? "";
-    const formValue = sensitive ? undefined : rawFormValue;
-    const formState = snapshotFormState(
-      rawFormValue,
-      formDefaultValue,
-      Object.prototype.hasOwnProperty.call(attrs, "value"),
-      sensitive,
-    );
-    if (sensitive) delete attrs.value;
-
-    nodes.push({
-      backendNodeId,
-      parentBackendNodeId,
-      ...(context.frameId ? { frameId: context.frameId } : {}),
-      ownerFrameBackendNodeId: context.ownerFrameBackendNodeId,
-      tag,
-      attrs,
-      rect,
-      localRect,
-      paintOrder,
-      position,
-      pointerEvents,
-      cursor,
-      rendered,
-      textContent,
-      ...(formValue !== undefined ? { formValue } : {}),
-      ...(tag === "input" || tag === "textarea"
-        ? {
-            formPlaceholder: attrs.placeholder ?? "",
-            ...(!sensitive ? { formDefaultValue } : {}),
-            ...(formState ? { formState } : {}),
-          }
-        : {}),
-      ...(checkedInputs.has(n) ? { formValue: "true", formState: "filled" } : {}),
-      ...(selectedOptions.has(n) ? { formValue: attrs.value ?? textContent ?? "" } : {}),
-    });
-  }
-  return { nodes, excludedBackendNodeIds };
-}
-
-interface ParseFrameDocumentsResult {
-  frameGeometryIssues: FrameProjectionIssue[];
-  iframeNodes: CapturedIframeNodes;
-  frameOwnerBackendNodeIds: Map<string, number>;
-  frameParentIds: Map<string, string>;
-  excludedBackendNodeIds: Set<number>;
-}
-
-async function parseChildFrameDocuments(
-  documents: SnapshotDocument[],
-  strings: string[],
-  parentDocIndex: number,
-  parentContext: FrameContext,
-  geometry: GeometryContext,
-  signal?: AbortSignal,
-  visited = new Set<number>(),
-): Promise<ParseFrameDocumentsResult> {
-  const frameGeometryIssues: FrameProjectionIssue[] = [];
-  const iframeNodes: CapturedIframeNodes = new Map();
-  const frameOwnerBackendNodeIds = new Map<string, number>();
-  const frameParentIds = new Map<string, string>();
-  const excludedBackendNodeIds = new Set<number>();
-  const parentDoc = documents[parentDocIndex];
-  const cdi = sparseIndexMap(parentDoc?.nodes?.contentDocumentIndex);
-  if (cdi.size === 0) {
-    return {
-      iframeNodes,
-      frameOwnerBackendNodeIds,
-      frameParentIds,
-      excludedBackendNodeIds,
-      frameGeometryIssues,
-    };
-  }
-
-  const parentBackendIds = parentDoc?.nodes?.backendNodeId ?? [];
-
-  const children = [...cdi].flatMap(([nodeArrayIdx, childDocIndex]) => {
-    const childDoc = documents[childDocIndex];
-    const iframeBackendId = parentBackendIds[nodeArrayIdx];
-    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: source.frameId,
-      target: source.target,
-      ownerFrameBackendNodeId: iframeBackendId,
-      projection,
-      coordinates,
-      layoutUnitsPerCssPixel: parentContext.layoutUnitsPerCssPixel,
-    };
-    const nextVisited = new Set(visited);
-    nextVisited.add(childDocIndex);
-    const parsed = parseDocumentNodes(childDoc, strings, childContext);
-    iframeNodes.set(iframeBackendId, parsed.nodes);
-    if (childContext.frameId) {
-      frameOwnerBackendNodeIds.set(childContext.frameId, iframeBackendId);
-      if (parentContext.frameId) frameParentIds.set(childContext.frameId, parentContext.frameId);
-    }
-    for (const id of parsed.excludedBackendNodeIds) excludedBackendNodeIds.add(id);
-
-    const nested = await parseChildFrameDocuments(
-      documents,
-      strings,
-      childDocIndex,
-      childContext,
-      geometry,
-      signal,
-      nextVisited,
-    );
-    frameGeometryIssues.push(...nested.frameGeometryIssues);
-    for (const [nestedFrameId, nestedNodes] of nested.iframeNodes) {
-      iframeNodes.set(nestedFrameId, nestedNodes);
-    }
-    for (const [frameId, ownerBackendNodeId] of nested.frameOwnerBackendNodeIds) {
-      frameOwnerBackendNodeIds.set(frameId, ownerBackendNodeId);
-    }
-    for (const [frameId, parentFrameId] of nested.frameParentIds) {
-      frameParentIds.set(frameId, parentFrameId);
-    }
-    for (const id of nested.excludedBackendNodeIds) excludedBackendNodeIds.add(id);
-  }
-
-  return {
-    iframeNodes,
-    frameOwnerBackendNodeIds,
-    frameParentIds,
-    excludedBackendNodeIds,
-    frameGeometryIssues,
-  };
-}
-
-export async function captureViewModel(
-  cdp: CdpRunner,
-  tabId: number,
-  options: CaptureViewModelOptions = {},
-): Promise<CapturedViewModel> {
-  throwIfAborted(options.signal);
-  const target = options.target ?? { tabId };
-  const geometry = options.geometry ?? new GeometryContext(cdp, tabId, undefined, options.signal);
-  let metrics: LayoutMetrics = {};
-  try {
-    metrics = await geometry.layoutMetrics(target);
-  } catch (error) {
-    if (isAbortError(error)) throw error;
-    console.debug("[bsk capture] layout metrics unavailable", error);
-  }
-  throwIfAborted(options.signal);
-  const viewport: Viewport = {
-    width: metrics.cssLayoutViewport?.clientWidth ?? 0,
-    height: metrics.cssLayoutViewport?.clientHeight ?? 0,
-  };
-  const layoutUnitsPerCssPixel = snapshotLayoutScale(metrics);
-
-  await cdp.send(tabId, "DOMSnapshot.enable", {});
-  throwIfAborted(options.signal);
-  const snap = await cdp.send<SnapshotReply>(tabId, "DOMSnapshot.captureSnapshot", {
-    computedStyles: REQUESTED_STYLES,
-    includePaintOrder: true,
-    includeDOMRects: true,
-  });
-  throwIfAborted(options.signal);
-
-  const strings = snap.strings ?? [];
-  const documents = snap.documents ?? [];
-  const doc0 = documents[0];
-  if (!doc0?.nodes?.backendNodeId) {
-    return {
-      nodes: [],
-      viewport,
-      iframeNodes: new Map(),
-      excludedBackendNodeIds: new Set(),
-    };
-  }
-
-  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,
-    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, topContext);
-  const nodes = mainParsed.nodes;
-  const excludedBackendNodeIds = new Set(mainParsed.excludedBackendNodeIds);
-
-  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);
-  }
-
-  await enrichFormControlStates(cdp, tabId, [nodes, ...iframeNodes.values()], options.signal);
-  throwIfAborted(options.signal);
-
-  const frameNodes = new Map<string, CapturedNode[]>();
-  if (topContext.frameId) frameNodes.set(topContext.frameId, nodes);
-  for (const iframeFrameNodes of iframeNodes.values()) {
-    const frameId = iframeFrameNodes.find((node) => node.frameId)?.frameId;
-    if (frameId) frameNodes.set(frameId, iframeFrameNodes);
-  }
-  for (const [frameId, ownerBackendNodeId] of frameParsed.frameOwnerBackendNodeIds) {
-    if (!frameNodes.has(frameId)) {
-      frameNodes.set(frameId, iframeNodes.get(ownerBackendNodeId) ?? []);
-    }
-  }
-
-  return {
-    nodes,
-    viewport,
-    iframeNodes,
-    frameNodes,
-    frameGeometryIssues: [
-      ...(topContext.projection.status === "available" ? [] : [topContext.projection]),
-      ...frameParsed.frameGeometryIssues,
-    ],
-    frameOwnerBackendNodeIds: frameParsed.frameOwnerBackendNodeIds,
-    frameParentIds: frameParsed.frameParentIds,
-    ...(topContext.frameId ? { rootFrameId: topContext.frameId } : {}),
-    excludedBackendNodeIds,
-  };
-}

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

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

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

@@ -0,0 +1,155 @@
+import type { Viewport } from "@browser-skill/vom";
+import type { CdpFrame, CdpTarget } from "@/browser-driver/frame-graph";
+import { isOverlayHostNode } from "@/lib/overlay-bridge";
+import type { FrameProjectionIssue } from "../geometry/coordinate-types";
+import { createCaptureCheckpoint } from "./capture-abort";
+import type { CapturedNode } from "./capture-types";
+import type { FrameOwnedAxNode } from "./frame-document";
+
+/** Bounds retain their raw snapshot document layout units until normalization. */
+export interface SnapshotLayout {
+  readonly boundsSpace: "snapshot-document-layout";
+  bounds?: number[];
+  styles: Readonly<Record<string, string>>;
+}
+
+export interface DecodedNode extends Omit<CapturedNode, "rect" | "localRect" | "rendered"> {
+  nodeType?: number;
+  layout?: SnapshotLayout;
+}
+
+export interface NodeFacts extends CapturedNode {
+  nodeType?: number;
+  layout?: SnapshotLayout;
+}
+
+export interface DocumentIndex<T extends DecodedNode = NodeFacts> {
+  readonly nodes: ReadonlyMap<number, T>;
+  readonly excludedBackendNodeIds: ReadonlySet<number>;
+}
+
+export interface DecodedDocument {
+  nodes: DecodedNode[];
+}
+
+/** All snapshot nodes participate, including document and shadow roots. This
+ * preserves overlay propagation when the semantic adapter omits those nodes. */
+export async function buildDocumentIndex<T extends DecodedNode>(
+  input: readonly T[],
+  signal?: AbortSignal,
+): Promise<DocumentIndex<T>> {
+  const checkpoint = createCaptureCheckpoint(signal);
+  const nodes = new Map<number, T>();
+  const overlayByNode = new Map<number, boolean>();
+  const excludedBackendNodeIds = new Set<number>();
+  for (let i = 0; i < input.length; i++) {
+    if (i % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
+    const node = input[i];
+    nodes.set(node.backendNodeId, node);
+  }
+  let work = 0;
+  for (const node of input) {
+    if (work++ % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
+    if (overlayByNode.has(node.backendNodeId)) continue;
+    const path: DecodedNode[] = [];
+    const visiting = new Set<number>();
+    let current: DecodedNode | undefined = node;
+    let overlay = false;
+    while (current && !overlayByNode.has(current.backendNodeId)) {
+      if (work++ % 256 === 0) {
+        const pending = checkpoint();
+        if (pending) await pending;
+      }
+      if (visiting.has(current.backendNodeId)) {
+        // Only an overlay inside the cycle may mark the cycle and its descendants.
+        overlay = path
+          .slice(path.findIndex((item) => item.backendNodeId === current!.backendNodeId))
+          .some((item) => isOverlayHostNode(item.tag, Object.keys(item.attrs)));
+        break;
+      }
+      visiting.add(current.backendNodeId);
+      path.push(current);
+      if (current.parentBackendNodeId === null) {
+        current = undefined;
+        break;
+      }
+      current = nodes.get(current.parentBackendNodeId);
+    }
+    if (current && overlayByNode.has(current.backendNodeId))
+      overlay = overlayByNode.get(current.backendNodeId)!;
+    for (let i = path.length - 1; i >= 0; i--) {
+      if (work++ % 256 === 0) {
+        const pending = checkpoint();
+        if (pending) await pending;
+      }
+      const item = path[i];
+      overlay = overlay || isOverlayHostNode(item.tag, Object.keys(item.attrs));
+      overlayByNode.set(item.backendNodeId, overlay);
+      if (overlay) excludedBackendNodeIds.add(item.backendNodeId);
+    }
+  }
+  return { nodes, excludedBackendNodeIds };
+}
+
+export interface DocumentIdentity {
+  attachmentId: string;
+  target: CdpTarget;
+  frameId: string;
+  documentElementBackendNodeId: number;
+}
+
+/** Narrow input shared by the existing semantic scene/hover consumers. */
+export interface CapturedSceneInput {
+  nodes: CapturedNode[];
+  viewport: Viewport;
+  rootFrameId?: string;
+  excludedBackendNodeIds: ReadonlySet<number>;
+}
+
+export interface CaptureIssue {
+  /** Owner failure or inherited blockage; absent for other geometry failures. */
+  projectionIssue?: FrameProjectionIssue;
+  target: CdpTarget;
+  frameId?: string;
+  stage: "dom" | "ax" | "identity" | "ownership" | "geometry" | "forms";
+  reason:
+    | "document-changed"
+    | "identity-unavailable"
+    | "identity-unverified"
+    | "capture-unavailable"
+    | "frame-ownership-unresolved"
+    | "geometry-unavailable";
+}
+
+export interface DocumentFacts<T extends FrameOwnedAxNode> {
+  readonly frame: CdpFrame;
+  readonly identity?: DocumentIdentity;
+  readonly index: DocumentIndex;
+  readonly domNodes: CapturedNode[];
+  readonly axNodes: T[];
+}
+
+export interface ObservationFacts<T extends FrameOwnedAxNode> {
+  readonly rootFrameId: string;
+  readonly viewport: Viewport;
+  readonly documents: readonly DocumentFacts<T>[];
+  readonly issues: readonly CaptureIssue[];
+  readonly startedAt: number;
+  readonly finishedAt: number;
+}
+
+export interface CapturedSurfaceProbe {
+  triggerBackendNodeId: number;
+  triggerPoint?: { x: number; y: number };
+  triggerAction: "hover" | "focus" | string;
+  subItems: string[];
+  confidence?: "high" | "medium" | "low";
+}
+
+export type { CapturedNode } from "./capture-types";

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

@@ -0,0 +1,155 @@
+import type { CdpRunner } from "../shared";
+import { isAbortError, throwIfAborted } from "./capture-abort";
+import type { CapturedNode } from "./capture-types";
+
+interface RuntimeEvaluateReply {
+  result?: { deepSerializedValue?: DeepSerializedValue };
+}
+const MAX_FORM_ENRICH_CONTROLS = 250;
+
+interface CapturedFormState {
+  value?: string;
+  defaultValue?: string;
+  placeholder?: string;
+  state?: "empty" | "filled" | "default";
+  sensitive?: boolean;
+}
+
+interface DeepSerializedValue {
+  type: string;
+  value?: unknown;
+}
+
+function formStateBatchExpression(maxControls: number): string {
+  return `(() => {
+    const maxControls = ${JSON.stringify(maxControls)};
+    let remaining = maxControls;
+    const controlSelector = "input,textarea,select";
+    const controlState = (el) => {
+      const tag = el.tagName.toLowerCase();
+      const type = tag === "input" ? String(el.type || "text").toLowerCase() : tag;
+      const sensitive = type === "password" || type === "credit-card";
+      const rawValue = typeof el.value === "string" ? el.value : "";
+      const defaultValue = typeof el.defaultValue === "string" ? el.defaultValue : "";
+      const placeholder = typeof el.placeholder === "string" ? el.placeholder : "";
+      const state = rawValue === "" ? "empty" : rawValue === defaultValue ? "default" : "filled";
+      return {
+        state,
+        sensitive,
+        placeholder,
+        ...(sensitive ? {} : { value: rawValue, defaultValue }),
+      };
+    };
+    const controls = [];
+    const collect = (doc) => {
+      for (const el of Array.from(doc.querySelectorAll(controlSelector))) {
+        if (remaining <= 0) break;
+        // Deep serialization supplies the node's backend id. Keep the
+        // state as JSON so decoding needs no general-purpose V8 deserializer.
+        controls.push([el, JSON.stringify(controlState(el))]);
+        remaining -= 1;
+      }
+      for (const frame of Array.from(doc.querySelectorAll("iframe"))) {
+        if (remaining <= 0) break;
+        let childDoc = null;
+        try { childDoc = frame.contentDocument; } catch { childDoc = null; }
+        if (childDoc) collect(childDoc);
+      }
+    };
+    collect(document);
+    return controls;
+  })()`;
+}
+
+function formStatesByBackendId(result: RuntimeEvaluateReply): Map<number, CapturedFormState> {
+  const states = new Map<number, CapturedFormState>();
+  const serialized = result.result?.deepSerializedValue;
+  if (serialized?.type !== "array" || !Array.isArray(serialized.value)) return states;
+  for (const entry of serialized.value as DeepSerializedValue[]) {
+    if (entry?.type !== "array" || !Array.isArray(entry.value)) continue;
+    const [element, json] = entry.value as DeepSerializedValue[];
+    if (element?.type !== "node" || json?.type !== "string" || typeof json.value !== "string") {
+      continue;
+    }
+    const backendNodeId = (element.value as { backendNodeId?: number } | undefined)?.backendNodeId;
+    if (typeof backendNodeId !== "number" || !Number.isSafeInteger(backendNodeId)) continue;
+    try {
+      const state = JSON.parse(json.value) as CapturedFormState | null;
+      if (
+        !state ||
+        !["empty", "filled", "default"].includes(state.state ?? "") ||
+        typeof state.sensitive !== "boolean" ||
+        typeof state.placeholder !== "string" ||
+        (!state.sensitive &&
+          (typeof state.value !== "string" || typeof state.defaultValue !== "string"))
+      ) {
+        continue;
+      }
+      states.set(backendNodeId, state);
+    } catch {
+      // A malformed entry must not overwrite the snapshot's own state.
+    }
+  }
+  return states;
+}
+
+function applyFormStates(nodes: CapturedNode[], states: Map<number, CapturedFormState>): void {
+  for (const node of nodes) {
+    if (!["input", "textarea", "select"].includes(node.tag)) continue;
+    const state = states.get(node.backendNodeId);
+    if (!state) continue;
+    node.formState = state.state;
+    node.formPlaceholder = state.placeholder ?? "";
+    if (
+      state.sensitive ||
+      (node.tag === "input" && (node.attrs.type ?? "").toLowerCase() === "password")
+    ) {
+      delete node.formValue;
+      delete node.formDefaultValue;
+      delete node.attrs.value;
+    } else {
+      node.formDefaultValue = state.defaultValue ?? "";
+      if (state.value !== undefined) node.formValue = state.value;
+    }
+  }
+}
+
+export async function enrichFormControlStates(
+  cdp: CdpRunner,
+  tabId: number,
+  frameNodeGroups: CapturedNode[][],
+  signal?: AbortSignal,
+): Promise<boolean> {
+  const hasControls = frameNodeGroups.some((nodes) =>
+    nodes.some((node) => ["input", "textarea", "select"].includes(node.tag)),
+  );
+  if (!hasControls) return true;
+  const objectGroup = `bsk-vom-forms-${crypto.randomUUID()}`;
+  try {
+    throwIfAborted(signal);
+    const result = await cdp.send<RuntimeEvaluateReply>(tabId, "Runtime.evaluate", {
+      expression: formStateBatchExpression(MAX_FORM_ENRICH_CONTROLS),
+      objectGroup,
+      serializationOptions: {
+        serialization: "deep",
+        maxDepth: 3,
+        additionalParameters: { maxNodeDepth: 0, includeShadowTree: "none" },
+      },
+    });
+    throwIfAborted(signal);
+    // Backend ids are scoped to this capture's CDP target. OOPIF targets
+    // have separate enrichment calls and never share this lookup.
+    const states = formStatesByBackendId(result);
+    for (const nodes of frameNodeGroups) {
+      applyFormStates(nodes, states);
+    }
+    return true;
+  } catch (error) {
+    if (isAbortError(error)) throw error;
+    // Best-effort enrichment. DOMSnapshot/AX data still carries the nodes.
+    return false;
+  } finally {
+    await cdp.send(tabId, "Runtime.releaseObjectGroup", { objectGroup }).catch(() => undefined);
+    throwIfAborted(signal);
+  }
+}

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

@@ -1,178 +0,0 @@
-import type { CdpFrame, CdpFrameGraph } from "@/browser-driver/frame-graph";
-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 {
-  buildFrameDocuments,
-  type FrameAxBatch,
-  type FrameDocument,
-  type FrameOwnedAxNode,
-} from "./frame-document";
-
-export type FrameAxNode = FrameOwnedAxNode;
-export type CapturedFrameDocument<T extends FrameAxNode> = FrameDocument<T>;
-
-function throwIfAborted(signal?: AbortSignal): void {
-  if (signal?.aborted) throw new DOMException("observation aborted", "AbortError");
-}
-
-function isAbortError(err: unknown): boolean {
-  return err instanceof Error && err.name === "AbortError";
-}
-
-function transformFrameNodes(
-  nodes: CapturedNode[],
-  projection: GeometryProjection | null,
-): CapturedNode[] {
-  return nodes.map((node) => ({
-    ...node,
-    rect: projection
-      ? (() => {
-          const bounds = projectRectToViewport(node.rect, projection);
-          return bounds ? { x: bounds.x, y: bounds.y, w: bounds.width, h: bounds.height } : null;
-        })()
-      : null,
-  }));
-}
-
-async function captureMissingFrameDocuments(
-  cdp: CdpRunner,
-  tabId: number,
-  graph: CdpFrameGraph,
-  captured: CapturedViewModel,
-  geometry: GeometryContext,
-  signal?: AbortSignal,
-): Promise<void> {
-  if (!captured.frameNodes) captured.frameNodes = new Map();
-  if (!captured.frameOwnerBackendNodeIds) captured.frameOwnerBackendNodeIds = new Map();
-  if (!captured.frameParentIds) captured.frameParentIds = new Map();
-
-  for (const frame of graph.frames) {
-    if (!frame.target.sessionId || captured.frameNodes.has(frame.frameId)) continue;
-    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 geometry.targetProjection(frame.frameId);
-      } catch (err) {
-        if (isAbortError(err)) throw err;
-        console.debug("[bsk observation] child frame geometry projection failed", {
-          frameId: frame.frameId,
-          err,
-        });
-      }
-      const rootFrameId = child.rootFrameId ?? frame.frameId;
-      const childFrames = child.frameNodes ?? new Map<string, CapturedNode[]>();
-      if (!childFrames.has(rootFrameId)) childFrames.set(rootFrameId, child.nodes);
-      if (rootFrameId !== frame.frameId && !childFrames.has(frame.frameId)) {
-        childFrames.set(
-          frame.frameId,
-          child.nodes.map((node) => ({ ...node, frameId: frame.frameId })),
-        );
-      }
-      for (const [childFrameId, nodes] of childFrames) {
-        captured.frameNodes.set(childFrameId, transformFrameNodes(nodes, projection));
-      }
-      if (frame.ownerBackendNodeId !== undefined) {
-        captured.iframeNodes.set(
-          frame.ownerBackendNodeId,
-          captured.frameNodes.get(frame.frameId) ?? [],
-        );
-        captured.frameOwnerBackendNodeIds.set(frame.frameId, frame.ownerBackendNodeId);
-      }
-      if (frame.parentFrameId) captured.frameParentIds.set(frame.frameId, frame.parentFrameId);
-      for (const [childFrameId, ownerBackendNodeId] of child.frameOwnerBackendNodeIds ?? []) {
-        captured.frameOwnerBackendNodeIds.set(childFrameId, ownerBackendNodeId);
-      }
-      for (const [childFrameId, parentFrameId] of child.frameParentIds ?? []) {
-        captured.frameParentIds.set(childFrameId, parentFrameId);
-      }
-    } catch (err) {
-      if (isAbortError(err)) throw err;
-      console.debug("[bsk observation] child frame DOM capture failed", {
-        frameId: frame.frameId,
-        err,
-      });
-    }
-  }
-}
-
-async function captureAxTrees<T extends FrameAxNode>(
-  cdp: CdpRunner,
-  tabId: number,
-  discoveredFrames: CdpFrame[],
-  captured: CapturedViewModel,
-  signal?: AbortSignal,
-): Promise<FrameAxBatch<T>[]> {
-  let frames = [...discoveredFrames];
-  const capturedFrameIds = [...(captured.frameNodes?.keys() ?? [])];
-  if (frames.length === 0) {
-    const rootFrameId = captured.rootFrameId ?? capturedFrameIds[0] ?? "root";
-    frames = [{ frameId: rootFrameId, target: { tabId } }];
-  }
-  for (const frameId of capturedFrameIds) {
-    if (!frames.some((frame) => frame.frameId === frameId)) {
-      frames.push({ frameId, target: { tabId } });
-    }
-  }
-
-  let firstFailure: unknown;
-  const trees = await Promise.all(
-    frames.map(async (frame): Promise<FrameAxBatch<T>> => {
-      try {
-        throwIfAborted(signal);
-        await sendToCdpTarget(cdp, frame.target, "Accessibility.enable", {});
-        const result = await sendToCdpTarget<{ nodes?: T[] }>(
-          cdp,
-          frame.target,
-          "Accessibility.getFullAXTree",
-          frame.frameId === "root" ? {} : { frameId: frame.frameId },
-        );
-        throwIfAborted(signal);
-        return {
-          frame,
-          nodes: result.nodes ?? [],
-        };
-      } catch (err) {
-        if (isAbortError(err)) throw err;
-        firstFailure ??= err;
-        console.debug("[bsk observation] frame AX capture failed", {
-          frameId: frame.frameId,
-          err,
-        });
-        return { frame, nodes: [] };
-      }
-    }),
-  );
-  const capturedNodeCount = [...captured.iframeNodes.values()].reduce(
-    (count, nodes) => count + nodes.length,
-    captured.nodes.length,
-  );
-  if (firstFailure && capturedNodeCount === 0 && trees.every((tree) => tree.nodes.length === 0)) {
-    throw firstFailure;
-  }
-  return trees;
-}
-
-export async function captureFrameData<T extends FrameAxNode>(
-  cdp: CdpRunner,
-  tabId: number,
-  captured: CapturedViewModel,
-  signal?: AbortSignal,
-  geometry = new GeometryContext(cdp, tabId, undefined, signal),
-): Promise<CapturedFrameDocument<T>[]> {
-  const graph = await geometry.graph();
-  const frames = graph?.frames ?? [];
-  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);
-}

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

@@ -4,7 +4,8 @@ import {
   type CdpTarget,
   cdpTargetKey,
 } from "@/browser-driver/frame-graph";
-import type { CapturedNode, CapturedViewModel } from "./capture";
+import { createCaptureCheckpoint } from "./capture-abort";
+import type { CapturedNode } from "./capture-types";
 
 export interface FrameOwnedAxNode {
   nodeId: string;
@@ -23,6 +24,15 @@ export interface FrameDocument<T extends FrameOwnedAxNode> extends CdpFrame {
   contextScopeId: string;
   axNodes: T[];
   domNodes: CapturedNode[];
+  excludedBackendNodeIds?: ReadonlySet<number>;
+}
+
+/** Explicit snapshot document data used to join DOM and AX ownership. */
+export interface FrameDomInput {
+  nodes: CapturedNode[];
+  rootFrameId?: string;
+  frameNodes?: ReadonlyMap<string, CapturedNode[]>;
+  frameExcludedBackendNodeIds?: ReadonlyMap<string, ReadonlySet<number>>;
 }
 
 interface Ownership {
@@ -47,35 +57,25 @@ function targetBackendKey(target: CdpTarget, backendNodeId: number): string {
 function frameList<T extends FrameOwnedAxNode>(
   graph: CdpFrameGraph | null,
   batches: FrameAxBatch<T>[],
-  captured: CapturedViewModel,
 ): CdpFrame[] {
   const frames = new Map<string, CdpFrame>();
   for (const frame of graph?.frames ?? []) frames.set(frame.frameId, frame);
   for (const batch of batches) {
     if (!frames.has(batch.frame.frameId)) frames.set(batch.frame.frameId, batch.frame);
   }
-  for (const frameId of captured.frameNodes?.keys() ?? []) {
-    if (!frames.has(frameId))
-      frames.set(frameId, { frameId, target: { tabId: batches[0]?.frame.target.tabId ?? 0 } });
-  }
-  return [...frames.values()].map((frame) => {
-    const ownerBackendNodeId =
-      frame.ownerBackendNodeId ?? captured.frameOwnerBackendNodeIds?.get(frame.frameId);
-    const parentFrameId = frame.parentFrameId ?? captured.frameParentIds?.get(frame.frameId);
-    return {
-      ...frame,
-      ...(ownerBackendNodeId !== undefined ? { ownerBackendNodeId } : {}),
-      ...(parentFrameId ? { parentFrameId } : {}),
-    };
-  });
+  return [...frames.values()];
 }
 
-export function buildFrameDocuments<T extends FrameOwnedAxNode>(
+export async function buildFrameDocuments<T extends FrameOwnedAxNode>(
   graph: CdpFrameGraph | null,
   batches: FrameAxBatch<T>[],
-  captured: CapturedViewModel,
-): FrameDocument<T>[] {
-  const frames = frameList(graph, batches, captured);
+  captured: FrameDomInput,
+  signal?: AbortSignal,
+  unresolved?: (frame: CdpFrame) => void,
+): Promise<FrameDocument<T>[]> {
+  const checkpoint = createCaptureCheckpoint(signal);
+  let work = 0;
+  const frames = frameList(graph, batches);
   const frameById = new Map(frames.map((frame) => [frame.frameId, frame]));
   const rootFrameId = graph?.rootFrameId ?? captured.rootFrameId ?? frames[0]?.frameId;
   const domNodesForFrame = (frameId: string): CapturedNode[] =>
@@ -83,54 +83,80 @@ export function buildFrameDocuments<T extends FrameOwnedAxNode>(
   const backendOwner = new Map<string, string>();
   for (const frame of frames) {
     for (const node of domNodesForFrame(frame.frameId)) {
+      if (work++ % 256 === 0) {
+        const pending = checkpoint();
+        if (pending) await pending;
+      }
       backendOwner.set(targetBackendKey(frame.target, node.backendNodeId), frame.frameId);
     }
   }
 
   const candidates = new Map<string, OwnedCandidate<T>>();
   for (const batch of batches) {
-    const nodeById = new Map(batch.nodes.map((node) => [node.nodeId, node]));
-    const ownershipByNodeId = new Map<string, Ownership>();
-    const resolving = new Set<string>();
-    const resolveOwnership = (node: T): Ownership => {
-      const cached = ownershipByNodeId.get(node.nodeId);
-      if (cached) return cached;
-      if (node.frameId && frameById.has(node.frameId)) {
-        const ownership = { frameId: node.frameId, strength: 4 };
-        ownershipByNodeId.set(node.nodeId, ownership);
-        return ownership;
-      }
-      if (typeof node.backendDOMNodeId === "number") {
-        const frameId = backendOwner.get(
-          targetBackendKey(batch.frame.target, node.backendDOMNodeId),
-        );
-        if (frameId) {
-          const ownership = { frameId, strength: 3 };
-          ownershipByNodeId.set(node.nodeId, ownership);
-          return ownership;
-        }
-      }
-      if (node.parentId && !resolving.has(node.nodeId)) {
-        const parent = nodeById.get(node.parentId);
-        if (parent) {
-          resolving.add(node.nodeId);
-          const inherited = resolveOwnership(parent);
-          resolving.delete(node.nodeId);
-          const ownership = {
-            frameId: inherited.frameId,
-            strength: Math.min(2, inherited.strength),
-          };
-          ownershipByNodeId.set(node.nodeId, ownership);
-          return ownership;
-        }
-      }
-      const ownership = { frameId: batch.frame.frameId, strength: 1 };
-      ownershipByNodeId.set(node.nodeId, ownership);
-      return ownership;
-    };
-
+    const nodeById = new Map<string, T>();
     for (const node of batch.nodes) {
-      const ownership = resolveOwnership(node);
+      if (work++ % 256 === 0) {
+        const pending = checkpoint();
+        if (pending) await pending;
+      }
+      nodeById.set(node.nodeId, node);
+    }
+    let reported = false;
+    const ownershipByNodeId = new Map<string, Ownership>();
+    for (const node of batch.nodes) {
+      const path: T[] = [];
+      const visiting = new Set<string>();
+      let current: T | undefined = node;
+      let ownership: Ownership = { frameId: batch.frame.frameId, strength: 1 };
+      while (current) {
+        if (work++ % 256 === 0) {
+          const pending = checkpoint();
+          if (pending) await pending;
+        }
+        const cached = ownershipByNodeId.get(current.nodeId);
+        if (cached) {
+          ownership = cached;
+          break;
+        }
+        if (visiting.has(current.nodeId)) break;
+        visiting.add(current.nodeId);
+        if (current.frameId) {
+          const frame = frameById.get(current.frameId);
+          // An explicit contradiction must not fall through to a guessed owner.
+          if (!frame || cdpTargetKey(frame.target) !== cdpTargetKey(batch.frame.target)) {
+            if (!reported) {
+              unresolved?.(batch.frame);
+              reported = true;
+            }
+            ownership = { frameId: "", strength: 0 };
+            break;
+          }
+          ownership = { frameId: frame.frameId, strength: 4 };
+          ownershipByNodeId.set(current.nodeId, ownership);
+          break;
+        }
+        const frameId =
+          typeof current.backendDOMNodeId === "number"
+            ? backendOwner.get(targetBackendKey(batch.frame.target, current.backendDOMNodeId))
+            : undefined;
+        if (frameId) {
+          ownership = { frameId, strength: 3 };
+          ownershipByNodeId.set(current.nodeId, ownership);
+          break;
+        }
+        path.push(current);
+        current = current.parentId ? nodeById.get(current.parentId) : undefined;
+      }
+      for (let i = path.length - 1; i >= 0; i--) {
+        if (work++ % 256 === 0) {
+          const pending = checkpoint();
+          if (pending) await pending;
+        }
+        ownership = { frameId: ownership.frameId, strength: Math.min(2, ownership.strength) };
+        ownershipByNodeId.set(path[i].nodeId, ownership);
+      }
+      if (!ownershipByNodeId.has(node.nodeId)) ownershipByNodeId.set(node.nodeId, ownership);
+      if (!ownership.frameId) continue;
       const key = targetNodeKey(batch.frame.target, node.nodeId);
       const existing = candidates.get(key);
       if (!existing || ownership.strength > existing.ownership.strength) {
@@ -144,6 +170,10 @@ export function buildFrameDocuments<T extends FrameOwnedAxNode>(
   );
   const axNodesByFrame = new Map<string, T[]>();
   for (const candidate of candidates.values()) {
+    if (work++ % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
     const { node, target, ownership } = candidate;
     const parentFrameId = node.parentId
       ? ownershipByTargetNode.get(targetNodeKey(target, node.parentId))
@@ -169,5 +199,6 @@ export function buildFrameDocuments<T extends FrameOwnedAxNode>(
     contextScopeId: frame.frameId,
     axNodes: axNodesByFrame.get(frame.frameId) ?? [],
     domNodes: domNodesForFrame(frame.frameId),
+    excludedBackendNodeIds: captured.frameExcludedBackendNodeIds?.get(frame.frameId),
   }));
 }

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

@@ -0,0 +1,325 @@
+import type { Viewport } from "@browser-skill/vom";
+import { type CdpFrame, type CdpTarget, cdpTargetKey } from "@/browser-driver/frame-graph";
+import { type GeometryProjection, projectRectToViewport } from "../geometry";
+import {
+  type FrameProjectionState,
+  projectSnapshotRect,
+  type SnapshotCoordinates,
+  snapshotCoordinates,
+  snapshotViewportRect,
+} from "../geometry/coordinate-types";
+import {
+  GeometryContext,
+  type LayoutMetrics,
+  snapshotLayoutScale,
+} from "../geometry/frame-context";
+import {
+  createCaptureCheckpoint,
+  isAbortError as isCaptureAbort,
+  throwIfAborted as throwCaptureAborted,
+} from "./capture-abort";
+import { buildDocumentIndex, type CaptureIssue, type DocumentIndex, type NodeFacts } from "./facts";
+import {
+  decodeDocument,
+  type SnapshotDocument,
+  type SnapshotReply,
+  snapshotFrameId,
+} from "./snapshot";
+
+export interface FrameContext {
+  frameId?: string;
+  ownerFrameBackendNodeId: number | null;
+  projection: FrameProjectionState | null;
+  targetProjection?: GeometryProjection | null;
+  target: CdpTarget;
+  coordinates: SnapshotCoordinates | null;
+}
+
+export interface NormalizedDocument {
+  nodes: NodeFacts[];
+  index: DocumentIndex;
+  documentElementBackendNodeId?: number;
+}
+
+/** Interpret one document using a supplied projection. No live reads or frame scheduling. */
+export async function normalizeDocument(
+  doc: SnapshotDocument,
+  strings: string[],
+  context: FrameContext,
+  signal?: AbortSignal,
+): Promise<NormalizedDocument> {
+  const decoded = await decodeDocument(doc, strings, signal);
+  const checkpoint = createCaptureCheckpoint(signal);
+  const nodes: NodeFacts[] = [];
+  for (let i = 0; i < decoded.nodes.length; i++) {
+    if (i % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
+    const node = decoded.nodes[i];
+    const bounds = node.layout?.bounds ?? [];
+    const input = snapshotViewportRect(
+      bounds,
+      { target: context.target, frameId: context.frameId },
+      context.coordinates,
+    );
+    const local = input?.rect;
+    let rect =
+      input && context.projection?.status === "available"
+        ? projectSnapshotRect(input, context.projection.projection)
+        : null;
+    if (rect && context.targetProjection !== undefined)
+      rect = context.targetProjection
+        ? projectRectToViewport(
+            { x: rect.x, y: rect.y, w: rect.width, h: rect.height },
+            context.targetProjection,
+          )
+        : null;
+    const visibility = node.layout?.styles.visibility || "visible";
+    const opacity = node.layout?.styles.opacity || "1";
+    nodes.push({
+      ...node,
+      ...(context.frameId ? { frameId: context.frameId } : {}),
+      ownerFrameBackendNodeId: context.ownerFrameBackendNodeId,
+      localRect: local ? { x: local.x, y: local.y, w: local.width, h: local.height } : null,
+      rect: rect ? { x: rect.x, y: rect.y, w: rect.width, h: rect.height } : null,
+      rendered:
+        bounds.length >= 4 &&
+        bounds.slice(0, 4).every(Number.isFinite) &&
+        bounds[2] > 0 &&
+        bounds[3] > 0 &&
+        visibility !== "hidden" &&
+        visibility !== "collapse" &&
+        (Number.parseFloat(opacity) || 0) > 0,
+    });
+  }
+  const index = await buildDocumentIndex(nodes, signal);
+  return {
+    nodes: nodes.filter(
+      (node) => !node.tag.startsWith("#") && !index.excludedBackendNodeIds.has(node.backendNodeId),
+    ),
+    index,
+    documentElementBackendNodeId: nodes.find(
+      (node) =>
+        node.nodeType === 1 &&
+        node.parentBackendNodeId !== null &&
+        index.nodes.get(node.parentBackendNodeId)?.nodeType === 9,
+    )?.backendNodeId,
+  };
+}
+
+export interface NormalizedFrameDocument extends NormalizedDocument {
+  frame: CdpFrame;
+}
+
+/** One target's snapshot. Source ownership is checked before interpreting any
+ * coordinates. Snapshot and live quad coordinates are deliberately not conflated. */
+export async function normalizeSnapshot(
+  snapshot: SnapshotReply,
+  target: CdpTarget,
+  frames: readonly CdpFrame[],
+  geometry: GeometryContext,
+  issues: CaptureIssue[],
+  signal?: AbortSignal,
+  rootFrameId?: string,
+): Promise<NormalizedFrameDocument[]> {
+  const strings = snapshot.strings ?? [];
+  const raw = snapshot.documents ?? [];
+  const ownerIds = new Set<number>();
+  for (const document of raw) {
+    for (const index of document.nodes?.contentDocumentIndex?.index ?? []) {
+      const id = document.nodes?.backendNodeId?.[index];
+      if (id !== undefined) ownerIds.add(id);
+    }
+  }
+  geometry.registerSnapshotOwners(target, ownerIds);
+  const frameById = new Map(frames.map((frame) => [frame.frameId, frame]));
+  const sources = new Map<string, SnapshotDocument>();
+  for (const doc of raw) {
+    const id = snapshotFrameId(doc, strings);
+    if (!id || !frameById.has(id) || sources.has(id)) {
+      issues.push({
+        target,
+        frameId: id,
+        stage: "ownership",
+        reason: "frame-ownership-unresolved",
+      });
+      continue;
+    }
+    sources.set(id, doc);
+  }
+  let metrics: LayoutMetrics = {};
+  try {
+    metrics = await geometry.layoutMetrics(target);
+  } catch (error) {
+    if (isCaptureAbort(error)) throw error;
+  }
+  const viewport: Viewport = {
+    width: metrics.cssLayoutViewport?.clientWidth ?? 0,
+    height: metrics.cssLayoutViewport?.clientHeight ?? 0,
+  };
+  const layoutUnitsPerCssPixel = snapshotLayoutScale(metrics);
+  const viewportAvailable = [viewport.width, viewport.height].every(
+    (size) => Number.isFinite(size) && size > 0,
+  );
+
+  const children = new Map<string, CdpFrame[]>();
+  const pending: CdpFrame[] = [];
+  for (const frame of frames) {
+    if (!frame.parentFrameId || !frameById.has(frame.parentFrameId)) pending.push(frame);
+    else {
+      const siblings = children.get(frame.parentFrameId);
+      if (siblings) siblings.push(frame);
+      else children.set(frame.parentFrameId, [frame]);
+    }
+  }
+  const projections = new Map<string, FrameProjectionState | null>();
+  const result: NormalizedFrameDocument[] = [];
+  let targetProjection: GeometryProjection | null = null;
+  const targetRoot = rootFrameId ? frameById.get(rootFrameId) : undefined;
+  if (target.sessionId && targetRoot) {
+    try {
+      const known = await geometry.frame(targetRoot.frameId);
+      if (known && cdpTargetKey(known.target) === cdpTargetKey(target))
+        targetProjection = await geometry.targetProjection(targetRoot.frameId);
+    } catch (error) {
+      if (isCaptureAbort(error)) throw error;
+    }
+  }
+  const checkpoint = createCaptureCheckpoint(signal);
+  const visited = new Set<string>();
+  const remaining = frames[Symbol.iterator]();
+  for (let cursor = 0; visited.size < frames.length; cursor++) {
+    if (cursor >= pending.length) {
+      let next = remaining.next();
+      while (!next.done && visited.has(next.value.frameId)) next = remaining.next();
+      if (next.done) break;
+      pending.push(next.value);
+    }
+    if (cursor % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
+    const frame = pending[cursor];
+    if (visited.has(frame.frameId)) continue;
+    visited.add(frame.frameId);
+    for (const child of children.get(frame.frameId) ?? []) pending.push(child);
+    const doc = sources.get(frame.frameId);
+    if (!doc) continue;
+    const source = { target, frameId: frame.frameId };
+    const coordinates = snapshotCoordinates(
+      doc,
+      layoutUnitsPerCssPixel,
+      frame.frameId === rootFrameId
+        ? { x: metrics.cssLayoutViewport?.pageX, y: metrics.cssLayoutViewport?.pageY }
+        : undefined,
+    );
+    let state: FrameProjectionState | null =
+      frame.frameId === rootFrameId
+        ? viewportAvailable && coordinates
+          ? {
+              status: "available",
+              projection: {
+                source,
+                geometry: { sourceClips: [], edges: [], topViewport: viewport },
+              },
+            }
+          : { status: "unavailable", source, reason: "snapshot-coordinates-unavailable" }
+        : (projections.get(frame.frameId) ?? null);
+    if (!state && frame.frameId !== rootFrameId)
+      issues.push({
+        target,
+        frameId: frame.frameId,
+        stage: "ownership",
+        reason: "frame-ownership-unresolved",
+      });
+    if (!coordinates && (!state || state.status === "available"))
+      state = { status: "unavailable", source, reason: "snapshot-coordinates-unavailable" };
+    projections.set(frame.frameId, state);
+    const projection = state?.status === "available" ? state.projection : null;
+    if (!projection || (target.sessionId && !targetProjection))
+      issues.push({
+        target,
+        frameId: frame.frameId,
+        stage: "geometry",
+        reason: "geometry-unavailable",
+        ...(state && state.status !== "available" ? { projectionIssue: state } : {}),
+      });
+
+    // Only direct siblings share this pool. Keep normalization in its existing
+    // breadth-first order, independent of owner read completion order.
+    const siblings = (children.get(frame.frameId) ?? []).filter((child) =>
+      sources.has(child.frameId),
+    );
+    const edge = projection?.geometry.edges[0];
+    const clips = edge
+      ? [edge.destinationQuad, ...(edge.destinationClips ?? [])]
+      : (projection?.geometry.sourceClips ?? []);
+    let next = 0;
+    let failure: unknown;
+    await Promise.all(
+      Array.from({ length: Math.min(4, siblings.length) }, async () => {
+        while (next < siblings.length && !signal?.aborted && !failure) {
+          const child = siblings[next++];
+          const childSource = { target, frameId: child.frameId };
+          if (!projection) {
+            projections.set(
+              child.frameId,
+              state && state.status !== "available"
+                ? {
+                    status: "blocked",
+                    source: childSource,
+                    cause: state.status === "blocked" ? state.cause : state,
+                  }
+                : null,
+            );
+            continue;
+          }
+          if (child.ownerBackendNodeId === undefined) {
+            projections.set(child.frameId, null);
+            continue;
+          }
+          if (!snapshotCoordinates(sources.get(child.frameId)!, layoutUnitsPerCssPixel)) {
+            projections.set(child.frameId, {
+              status: "unavailable",
+              source: childSource,
+              reason: "snapshot-coordinates-unavailable",
+            });
+            continue;
+          }
+          try {
+            projections.set(
+              child.frameId,
+              await geometry.snapshotProjection(
+                childSource,
+                child.ownerBackendNodeId,
+                clips,
+                viewport,
+              ),
+            );
+          } catch (error) {
+            failure ??= error;
+          }
+        }
+      }),
+    );
+    // Join active reads and their cleanup before returning cancellation.
+    if (failure) throw failure;
+    throwCaptureAborted(signal);
+    const normalized = await normalizeDocument(
+      doc,
+      strings,
+      {
+        frameId: frame.frameId,
+        ownerFrameBackendNodeId: frame.ownerBackendNodeId ?? null,
+        projection: state,
+        target,
+        ...(target.sessionId ? { targetProjection } : {}),
+        coordinates,
+      },
+      signal,
+    );
+    result.push({ ...normalized, frame });
+  }
+  return result;
+}

apps/extension/src/tools/vom/record-safe-observation.ts

@@ -2,7 +2,10 @@ import type { Rect, RenderedRef, VomResult } from "@browser-skill/vom";
 import type { CdpTarget } from "@/browser-driver/frame-graph";
 import { readRecordingDocumentIdentity } from "@/shared/recording-document-identity";
 import type { CapturedSurfaceProbe } from "./capture";
-import type { CapturedFrameDocument, FrameAxNode } from "./frame-capture";
+import type {
+  FrameDocument as CapturedFrameDocument,
+  FrameOwnedAxNode as FrameAxNode,
+} from "./frame-document";
 
 /** Frame identity needed to resolve an `@eN` that lives in an iframe. */
 export interface CaptureVomFrame {

apps/extension/src/tools/vom/semantic-graph/build.ts

@@ -61,8 +61,9 @@ export function buildSemanticGraph(input: BuildSemanticGraphInput): SemanticGrap
         dom,
         sourceOrder: index,
         excluded:
-          document.frameId === rootFrameId &&
-          input.excludedBackendNodeIds?.has(dom.backendNodeId) === true,
+          document.excludedBackendNodeIds?.has(dom.backendNodeId) === true ||
+          (document.frameId === rootFrameId &&
+            input.excludedBackendNodeIds?.has(dom.backendNodeId) === true),
       };
       nodes.set(id, node);
       frameNodeIds.push(id);
@@ -90,9 +91,10 @@ export function buildSemanticGraph(input: BuildSemanticGraphInput): SemanticGrap
           ax,
           sourceOrder: document.domNodes.length + index,
           excluded:
-            document.frameId === rootFrameId &&
             typeof ax.backendDOMNodeId === "number" &&
-            input.excludedBackendNodeIds?.has(ax.backendDOMNodeId) === true,
+            (document.excludedBackendNodeIds?.has(ax.backendDOMNodeId) === true ||
+              (document.frameId === rootFrameId &&
+                input.excludedBackendNodeIds?.has(ax.backendDOMNodeId) === true)),
         });
         frameNodeIds.push(id);
       }

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

@@ -0,0 +1,291 @@
+import { type CdpFrame, type CdpTarget, cdpTargetKey } from "@/browser-driver/frame-graph";
+import { createCaptureCheckpoint } from "./capture-abort";
+import type { CapturedNode } from "./capture-types";
+import type { DecodedDocument, DecodedNode } from "./facts";
+export const REQUESTED_STYLES = [
+  "position",
+  "pointer-events",
+  "cursor",
+  "visibility",
+  "opacity",
+] as const;
+const STYLE_COL = Object.fromEntries(
+  REQUESTED_STYLES.map((name, index) => [name, index]),
+) as Record<(typeof REQUESTED_STYLES)[number], number>;
+/** Sparse array format Chrome uses for infrequently-set per-node fields. */
+interface SparseArray {
+  index: number[];
+  value: number[];
+}
+
+interface RareBooleanData {
+  index: number[];
+}
+
+export interface SnapshotDocument {
+  frameId?: string | number;
+  documentURL?: number;
+  scrollOffsetX?: number;
+  scrollOffsetY?: number;
+  nodes?: {
+    parentIndex?: number[];
+    nodeName?: number[];
+    nodeType?: number[];
+    backendNodeId?: number[];
+    attributes?: number[][];
+    /**
+     * Per-node text value (index into strings), set for `#text` / CDATA nodes.
+     * Element nodes carry -1. Same length as `backendNodeId`.
+     */
+    nodeValue?: number[];
+    /** Maps node array index → index into `documents[]` for frame content. */
+    contentDocumentIndex?: SparseArray;
+    inputValue?: SparseArray;
+    textValue?: SparseArray;
+    inputChecked?: RareBooleanData;
+    optionSelected?: RareBooleanData;
+  };
+  layout?: {
+    nodeIndex?: number[];
+    styles?: number[][];
+    bounds?: number[][];
+    paintOrders?: number[];
+  };
+}
+
+export function snapshotFrameId(document: SnapshotDocument, strings: string[]): string | undefined {
+  if (typeof document.frameId === "string") return document.frameId || undefined;
+  if (typeof document.frameId === "number") return str(strings, document.frameId) || undefined;
+  return undefined;
+}
+
+export interface SnapshotReply {
+  strings?: string[];
+  documents?: SnapshotDocument[];
+}
+
+function isSensitiveFormControl(node: Pick<CapturedNode, "tag" | "attrs">): boolean {
+  return node.tag === "input" && (node.attrs.type ?? "").toLowerCase() === "password";
+}
+
+function snapshotFormState(
+  value: string | undefined,
+  defaultValue: string,
+  hasDefaultValue: boolean,
+  sensitive: boolean,
+): CapturedNode["formState"] {
+  if (sensitive) {
+    if (value === undefined && !hasDefaultValue) return undefined;
+    return (value ?? defaultValue) === "" ? "empty" : "filled";
+  }
+  if (value === undefined) return undefined;
+  if (value === "") return "empty";
+  return value === defaultValue ? "default" : "filled";
+}
+
+function str(strings: string[], idx: number | undefined): string {
+  if (idx === undefined || idx < 0) return "";
+  return strings[idx] ?? "";
+}
+
+export function sparseIndexMap(sparse: SparseArray | undefined): Map<number, number> {
+  const out = new Map<number, number>();
+  if (!sparse?.index || !sparse.value) return out;
+  for (let i = 0; i < sparse.index.length; i++) {
+    const nodeIndex = sparse.index[i];
+    const docIndex = sparse.value[i];
+    if (nodeIndex !== undefined && docIndex !== undefined) out.set(nodeIndex, docIndex);
+  }
+  return out;
+}
+
+export async function decodeDocument(
+  doc: SnapshotDocument,
+  strings: string[],
+  signal?: AbortSignal,
+): Promise<DecodedDocument> {
+  const checkpoint = createCaptureCheckpoint(signal);
+  const dn = doc.nodes;
+  const dl = doc.layout;
+  if (!dn?.backendNodeId) {
+    return { nodes: [] };
+  }
+
+  const count = dn.backendNodeId.length;
+  const layoutByNode = new Map<number, number>();
+  for (let i = 0; i < (dl?.nodeIndex?.length ?? 0); i++) {
+    if (i % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
+    layoutByNode.set(dl!.nodeIndex![i], i);
+  }
+
+  const inputValues = sparseIndexMap(dn.inputValue);
+  const textValues = sparseIndexMap(dn.textValue);
+  const checkedInputs = new Set(dn.inputChecked?.index ?? []);
+  const selectedOptions = new Set(dn.optionSelected?.index ?? []);
+
+  // Collect visible text from #text child nodes so element CapturedNodes
+  // carry a textContent value usable as a button/link label fallback.
+  // nodeValue is a parallel array: string index for text nodes, -1 otherwise.
+  const nodeTextContent = new Map<number, string[]>();
+  if (dn.nodeValue) {
+    for (let n = 0; n < count; n++) {
+      if (n % 256 === 0) {
+        const pending = checkpoint();
+        if (pending) await pending;
+      }
+      const nvIdx = dn.nodeValue[n] ?? -1;
+      if (nvIdx < 0) continue;
+      const text = str(strings, nvIdx).trim();
+      if (!text) continue;
+      const parentIdx = dn.parentIndex?.[n] ?? -1;
+      if (parentIdx >= 0) {
+        const existing = nodeTextContent.get(parentIdx);
+        if (existing) existing.push(text);
+        else nodeTextContent.set(parentIdx, [text]);
+      }
+    }
+  }
+
+  // Decode fields without assigning a coordinate projection or semantic policy.
+  const nodes: DecodedNode[] = [];
+  for (let n = 0; n < count; n++) {
+    if (n % 256 === 0) {
+      const pending = checkpoint();
+      if (pending) await pending;
+    }
+    const backendNodeId = dn.backendNodeId[n];
+    const parentIdx = dn.parentIndex?.[n] ?? -1;
+    const parentBackendNodeId = parentIdx >= 0 ? (dn.backendNodeId[parentIdx] ?? null) : null;
+    const tag = str(strings, dn.nodeName?.[n]).toLowerCase();
+
+    const attrs: Record<string, string> = {};
+    const pairs = dn.attributes?.[n] ?? [];
+    for (let a = 0; a + 1 < pairs.length; a += 2) {
+      attrs[str(strings, pairs[a]).toLowerCase()] = str(strings, pairs[a + 1]);
+    }
+
+    const li = layoutByNode.get(n);
+    const styleRow = li === undefined ? [] : (dl?.styles?.[li] ?? []);
+    const styles: Record<string, string> = {};
+    for (const name of REQUESTED_STYLES) styles[name] = str(strings, styleRow[STYLE_COL[name]]);
+    const layout =
+      li === undefined
+        ? undefined
+        : {
+            boundsSpace: "snapshot-document-layout" as const,
+            bounds: dl?.bounds?.[li],
+            styles,
+          };
+
+    const textContent = nodeTextContent.get(n)?.join(" ");
+
+    const rawFormValueIndex = tag === "textarea" ? textValues.get(n) : inputValues.get(n);
+    const rawFormValue =
+      rawFormValueIndex !== undefined ? str(strings, rawFormValueIndex) : undefined;
+    const sensitive = isSensitiveFormControl({ tag, attrs });
+    const formDefaultValue = attrs.value ?? "";
+    const formValue = sensitive ? undefined : rawFormValue;
+    const formState = snapshotFormState(
+      rawFormValue,
+      formDefaultValue,
+      Object.prototype.hasOwnProperty.call(attrs, "value"),
+      sensitive,
+    );
+    if (sensitive) delete attrs.value;
+
+    nodes.push({
+      backendNodeId,
+      nodeType: dn.nodeType?.[n],
+      parentBackendNodeId,
+
+      tag,
+      attrs,
+      layout,
+      paintOrder: li === undefined ? 0 : (dl?.paintOrders?.[li] ?? 0),
+      position: styles.position || "static",
+      pointerEvents: styles["pointer-events"] || "auto",
+      cursor: styles.cursor || "auto",
+
+      textContent,
+      ...(formValue !== undefined ? { formValue } : {}),
+      ...(tag === "input" || tag === "textarea"
+        ? {
+            formPlaceholder: attrs.placeholder ?? "",
+            ...(!sensitive ? { formDefaultValue } : {}),
+            ...(formState ? { formState } : {}),
+          }
+        : {}),
+      ...(checkedInputs.has(n) ? { formValue: "true", formState: "filled" } : {}),
+      ...(selectedOptions.has(n) ? { formValue: attrs.value ?? textContent ?? "" } : {}),
+    });
+  }
+  return { nodes };
+}
+
+/** Snapshot membership and same-target edges are current response evidence.
+ * The earlier graph only supplies compatible metadata and cross-target edges. */
+export function describeSnapshotFrames(
+  snapshot: SnapshotReply,
+  target: CdpTarget,
+  hintById: ReadonlyMap<string, CdpFrame>,
+  pageUrl?: string,
+): { frames: CdpFrame[]; ids: Set<string>; rootFrameId?: string } {
+  const raw = snapshot.documents ?? [];
+  const strings = snapshot.strings ?? [];
+  const ids = new Set<string>();
+  const invalid = new Set<string>();
+  const frames = raw.map((doc) => {
+    const frameId = snapshotFrameId(doc, strings);
+    if (!frameId) return undefined;
+    if (ids.has(frameId)) invalid.add(frameId);
+    ids.add(frameId);
+    const hint = hintById.get(frameId);
+    const compatible =
+      hint && cdpTargetKey(hint.target) === cdpTargetKey(target) ? hint : undefined;
+    const url =
+      (doc.documentURL === undefined ? undefined : strings[doc.documentURL]) || compatible?.url;
+    return { frameId, target, ...(url ? { url } : {}) } as CdpFrame;
+  });
+  const root = frames[0];
+  if (root) {
+    const hint = hintById.get(root.frameId);
+    const parent = hint?.parentFrameId ? hintById.get(hint.parentFrameId) : undefined;
+    if (
+      target.sessionId &&
+      hint &&
+      cdpTargetKey(hint.target) === cdpTargetKey(target) &&
+      parent &&
+      cdpTargetKey(parent.target) !== cdpTargetKey(target)
+    ) {
+      root.parentFrameId = parent.frameId;
+      root.ownerBackendNodeId = hint.ownerBackendNodeId;
+    }
+    if (!target.sessionId && !root.url && pageUrl) root.url = pageUrl;
+  }
+  const owned = new Set<string>();
+  for (let i = 0; i < raw.length; i++) {
+    const edges = raw[i].nodes?.contentDocumentIndex;
+    const parent = frames[i];
+    if (!parent || !edges) continue;
+    for (let e = 0; e < edges.index.length; e++) {
+      const child = frames[edges.value[e]];
+      const owner = raw[i].nodes?.backendNodeId?.[edges.index[e]];
+      if (!child || owner === undefined) continue;
+      if (child === root || child === parent || owned.has(child.frameId)) {
+        invalid.add(child.frameId);
+        continue;
+      }
+      owned.add(child.frameId);
+      child.parentFrameId = parent.frameId;
+      child.ownerBackendNodeId = owner;
+    }
+  }
+  return {
+    frames: frames.filter((frame): frame is CdpFrame => !!frame && !invalid.has(frame.frameId)),
+    ids,
+    rootFrameId: root?.frameId,
+  };
+}