diff --git a/src/application/BrowserObservationService.test.ts b/src/application/BrowserObservationService.test.ts
index d2cdde1c27..2e5baf7954 100644
--- a/src/application/BrowserObservationService.test.ts
+++ b/src/application/BrowserObservationService.test.ts
@@ -3,9 +3,13 @@ import type { BrowserObservationPort } from "./BrowserObservationPort.js";
 import { listBrowserTargets } from "./BrowserObservationService.js";
 import type { BrowserTargetList } from "../domain/browserObservationSchemas.js";
 import { parseEvidence } from "../domain/evidence.js";
-import { AnalysisOutputError } from "../domain/analysisErrorCore.js";
+import {
+  AnalysisCancelledError,
+  AnalysisOutputError,
+} from "../domain/analysisErrorCore.js";
+import { projectAnalysisError } from "../domain/analysisErrorProjection.js";
 import { BrowserObservationError } from "../domain/browserObservationError.js";
-import { ok } from "../domain/result.js";
+import { err, ok } from "../domain/result.js";
 import { passiveNetworkCapture } from "../../tests/fixtures/passiveNetworkCapture.js";
 import { inspectWebPage } from "./BrowserObservationService.js";
 import { analyzeWebBundleInputSchema } from "../domain/webBundleAnalysis.js";
@@ -215,3 +219,71 @@ it("preserves a prior caller reason without admitting browser work", async () =>
   expect(result.error._tag).toBe("AnalysisCancelledError");
   expect(result.error.cause).toBe(reason);
 });
+
+it("keeps page cancellation when the retained inspection is incomplete", async () => {
+  const reason = { requested: "stop during page inspection" };
+  const partial = {
+    target: { target_id: "page" },
+    network: {},
+    capture_window: {},
+  };
+  const failure = new AnalysisCancelledError("inspect_web_page", {
+    cause: reason,
+    partialObservation: partial as never,
+  });
+  const browser = {
+    ...provider(async () => ok(report)),
+    inspectPage: async () => err(failure),
+  } as unknown as BrowserObservationPort;
+  const pageInput = inspectWebPageInputSchema.parse({
+    cdp_endpoint: input.cdp_endpoint.recorded,
+    allowed_origins: [],
+    target_id: "page",
+    observation_ms: 0,
+    include_script_sources: false,
+  });
+  const result = await inspectWebPage(browser, pageInput);
+  expect(result.ok).toBe(false);
+  if (result.ok) throw new Error("Expected cancellation");
+  expect(result.error).toBe(failure);
+  expect(result.error.cause).toBe(reason);
+  expect(result.error.partialObservation).toBe(partial);
+  expect(projectAnalysisError(result.error)).toMatchObject({
+    code: "cancelled",
+    details: { partial_observation: partial },
+  });
+});
+
+it("keeps bundle cancellation and an earlier failure when retained facts are incomplete", async () => {
+  const reason = { requested: "stop during bundle analysis" };
+  const partial = { observations: [], capture: { status: "partial" } };
+  const cancelled = new AnalysisCancelledError("analyze_web_bundle", {
+    cause: reason,
+    partialObservation: partial as never,
+  });
+  const timedOut = new BrowserObservationError(
+    "analyze_web_bundle",
+    "timeout",
+    { partialObservation: partial as never },
+  );
+  const selected = analyzeWebBundleInputSchema.parse({
+    cdp_endpoint: input.cdp_endpoint.recorded,
+    target_id: "page",
+    observation_ms: 0,
+  });
+  for (const failure of [cancelled, timedOut]) {
+    const browser = {
+      ...provider(async () => ok(report)),
+      analyzeBundle: async () => err(failure),
+    } as unknown as BrowserObservationPort;
+    const result = await analyzeWebBundle(browser, selected);
+    expect(result.ok).toBe(false);
+    if (result.ok) throw new Error("Expected the owner failure");
+    expect(result.error).toBe(failure);
+    expect(result.error.partialObservation).toBe(partial);
+  }
+  expect(projectAnalysisError(cancelled)).toMatchObject({
+    code: "cancelled",
+    details: { partial_observation: partial },
+  });
+});
diff --git a/src/application/BrowserObservationService.ts b/src/application/BrowserObservationService.ts
index 6251e9d4dd..189c71b36a 100644
--- a/src/application/BrowserObservationService.ts
+++ b/src/application/BrowserObservationService.ts
@@ -27,7 +27,6 @@ import { createBrowserEvidence } from "./BrowserEvidence.js";
 import { jsonValueSchema } from "../domain/jsonValue.js";
 import { completeProviderEvidence } from "./ProviderOperationExecution.js";
 import { webPageInspectionSchema } from "../domain/browserObservationSchemas.js";
-import { analysisErrorWithCleanupFailure } from "../domain/analysisErrorCleanup.js";
 
 /** List browser targets within the endpoint and origin scope in the request. */
 export const listBrowserTargets = async (
@@ -291,22 +290,7 @@ const retainBrowserObservation = (
     "capture" in partial
   ) {
     const bundle = webBundleAnalysisSchema.safeParse(partial);
-    if (!bundle.success) {
-      const malformed = new AnalysisOutputError(
-        errorOperation,
-        "Browser provider retained malformed completed bundle facts.",
-        { cause: bundle.error },
-      );
-      return err(
-        error.cleanupIncomplete
-          ? analysisErrorWithCleanupFailure(
-              malformed,
-              error,
-              errorOperation,
-            ).bindCleanupDependencies([malformed, error])
-          : malformed,
-      );
-    }
+    if (!bundle.success) return err(error);
     error.partialObservation = createBrowserEvidence(
       "analyze_web_bundle",
       input,
@@ -324,17 +308,7 @@ const retainBrowserObservation = (
   )
     return err(error);
   const inspection = webPageInspectionSchema.safeParse(partial);
-  if (!inspection.success) {
-    if (error instanceof AnalysisCancelledError)
-      return err(
-        new AnalysisOutputError(
-          errorOperation,
-          "Browser provider retained a malformed completed page inspection.",
-          { cause: inspection.error },
-        ),
-      );
-    return err(error);
-  }
+  if (!inspection.success) return err(error);
   const pageInput: InspectWebPageInput =
     "fetch_source_maps" in input
       ? (({ fetch_source_maps: _fetchSourceMaps, ...page }) => page)(input)
diff --git a/src/application/BrowserScenarioCaptureService.test.ts b/src/application/BrowserScenarioCaptureService.test.ts
index df187682a4..f4beda1580 100644
--- a/src/application/BrowserScenarioCaptureService.test.ts
+++ b/src/application/BrowserScenarioCaptureService.test.ts
@@ -1,10 +1,18 @@
 import { expect, it } from "vitest";
 
-import { AnalysisCancelledError } from "../domain/analysisErrorCore.js";
+import {
+  AnalysisCancelledError,
+  AnalysisOutputError,
+} from "../domain/analysisErrorCore.js";
+import { projectAnalysisError } from "../domain/analysisErrorProjection.js";
 import { BrowserObservationError } from "../domain/browserObservationError.js";
 import { parseEvidence } from "../domain/evidence.js";
 import { browserScenarioInputSchema } from "../domain/browserScenario.js";
-import { err } from "../domain/result.js";
+import type {
+  BrowserScenarioCapture,
+  BrowserScenarioPartialObservation,
+} from "../domain/browserScenarioCapture.js";
+import { err, ok } from "../domain/result.js";
 import { scriptScenarioFixture } from "../../tests/fixtures/webScriptCapture.js";
 import type { BrowserScenarioCapturePort } from "./BrowserScenarioCapturePort.js";
 import { captureBrowserScenario } from "./BrowserScenarioCaptureService.js";
@@ -103,3 +111,55 @@ it.each([
     expect(calls).toBe(0);
   },
 );
+
+it("keeps startup cancellation and its incomplete capture", async () => {
+  const reason = { requested: "stop during initial navigation" };
+  const completed = scriptScenarioFixture();
+  const {
+    completeness: _completeness,
+    steps: _steps,
+    browser,
+    ...retained
+  } = completed;
+  const partial: BrowserScenarioPartialObservation = {
+    kind: "browser-scenario-observation",
+    capture: {
+      ...retained,
+      browser: { ...browser, cleanup: "incomplete" },
+      steps: [],
+    },
+  };
+  const failure = new AnalysisCancelledError("capture_browser_scenario", {
+    cause: reason,
+    partialObservation: partial,
+  });
+  const provider: BrowserScenarioCapturePort = {
+    identity: () => ({ id: "fixture", name: "fixture", version: "1" }),
+    captureScenario: async () => err(failure),
+  };
+  const result = await captureBrowserScenario(provider, scenario);
+  expect(result.ok).toBe(false);
+  if (result.ok) throw new Error("Expected cancellation");
+  expect(result.error).toBe(failure);
+  expect(result.error.cause).toBe(reason);
+  expect(result.error.partialObservation).toBe(partial);
+  expect(projectAnalysisError(result.error)).toMatchObject({
+    code: "cancelled",
+    details: { partial_observation: partial },
+  });
+});
+
+it("rejects a successful capture that is not a completed scenario", async () => {
+  const provider: BrowserScenarioCapturePort = {
+    identity: () => ({ id: "fixture", name: "fixture", version: "1" }),
+    captureScenario: async () => ok({} as BrowserScenarioCapture),
+  };
+  const result = await captureBrowserScenario(provider, scenario);
+  expect(result.ok).toBe(false);
+  if (result.ok) throw new Error("Expected a completed-capture refusal");
+  expect(result.error).toBeInstanceOf(AnalysisOutputError);
+  expect(result.error.message).toContain(
+    "returned a malformed completed capture",
+  );
+  expect(result.error.partialObservation).toBeUndefined();
+});
diff --git a/src/application/BrowserScenarioCaptureService.ts b/src/application/BrowserScenarioCaptureService.ts
index 0a5bc26019..d51759228c 100644
--- a/src/application/BrowserScenarioCaptureService.ts
+++ b/src/application/BrowserScenarioCaptureService.ts
@@ -43,6 +43,8 @@ export const captureBrowserScenario = async (
       partial.kind === "browser-scenario-observation"
     ) {
       const report = browserScenarioCaptureSchema.safeParse(partial.capture);
+      // Only a completed capture becomes Evidence. An incomplete observation
+      // stays on the owner error, including typed cancellation.
       if (
         report.success &&
         report.data.steps.every(({ status }) => status === "completed")
@@ -52,16 +54,6 @@ export const captureBrowserScenario = async (
           report.data,
           provider.identity(),
         );
-      } else if (!report.success) {
-        if (captured.error instanceof AnalysisCancelledError)
-          return err(
-            new AnalysisOutputError(
-              OPERATION,
-              "Browser scenario provider retained a malformed completed capture.",
-              { cause: report.error },
-            ),
-          );
-        return captured;
       }
     }
     return captured;
diff --git a/src/application/WebRuntimeService.test.ts b/src/application/WebRuntimeService.test.ts
index 7e7c651486..029f326c0a 100644
--- a/src/application/WebRuntimeService.test.ts
+++ b/src/application/WebRuntimeService.test.ts
@@ -6,10 +6,14 @@ import {
   webListenersFixture,
 } from "./WebRuntimeService.fixture.js";
 import { err, ok } from "../domain/result.js";
-import { AnalysisTimeoutError } from "../domain/analysisErrorCore.js";
+import {
+  AnalysisCancelledError,
+  AnalysisOutputError,
+  AnalysisTimeoutError,
+} from "../domain/analysisErrorCore.js";
+import { projectAnalysisError } from "../domain/analysisErrorProjection.js";
 import { ProviderCleanupError } from "../domain/providerCleanupError.js";
 import { parseEvidence } from "../domain/evidence.js";
-import { AnalysisOutputError } from "../domain/analysisErrorCore.js";
 
 it("rejects malformed input and prior cancellation without calling a provider", async () => {
   const provider = recordingWebRuntimePort();
@@ -161,3 +165,61 @@ it("retains completed execution Evidence on late abort and keeps invalid output
   });
   if (!invalid.ok) expect(invalid.error).toBeInstanceOf(AnalysisOutputError);
 });
+
+it.each([
+  {
+    operation: "observe" as const,
+    partial: {
+      instrumentation: { cleanup: "unconfirmed" },
+      window: { requested_ms: 5 },
+    },
+  },
+  {
+    operation: "inspect" as const,
+    partial: {
+      selected_node: { selector: "#selected" },
+      listeners: [],
+    },
+  },
+])(
+  "keeps $operation cancellation when the retained observation is incomplete",
+  async ({ operation, partial }) => {
+    const reason = { requested: `stop incomplete ${operation}` };
+    const failure = new AnalysisCancelledError(
+      operation === "observe"
+        ? "observe_web_execution"
+        : "inspect_web_event_listeners",
+      { cause: reason, partialObservation: partial as never },
+    );
+    const service = new WebRuntimeService({
+      identity: () => ({
+        id: "web-runtime",
+        name: "Runtime fixture",
+        version: "1",
+      }),
+      observeExecution: async () => err(failure),
+      inspectEventListeners: async () => err(failure),
+    });
+    const result =
+      operation === "observe"
+        ? await service.observe({
+            cdp_endpoint: "http://127.0.0.1:9222",
+            target_id: "selected-page",
+            observation_ms: 5,
+          })
+        : await service.inspect({
+            cdp_endpoint: "http://127.0.0.1:9222",
+            target_id: "selected-page",
+            selector: "#selected",
+          });
+    expect(result.ok).toBe(false);
+    if (result.ok) throw new Error("Expected cancellation");
+    expect(result.error).toBe(failure);
+    expect(result.error.cause).toBe(reason);
+    expect(result.error.partialObservation).toBe(partial);
+    expect(projectAnalysisError(result.error)).toMatchObject({
+      code: "cancelled",
+      details: { partial_observation: partial },
+    });
+  },
+);
diff --git a/src/application/WebRuntimeService.ts b/src/application/WebRuntimeService.ts
index 38d2934545..af56acb546 100644
--- a/src/application/WebRuntimeService.ts
+++ b/src/application/WebRuntimeService.ts
@@ -56,14 +56,7 @@ export class WebRuntimeService {
           if (evidence.ok) result.error.partialObservation = evidence.value;
           else if (result.error instanceof AnalysisCancelledError)
             return evidence;
-        } else if (result.error instanceof AnalysisCancelledError)
-          return err(
-            new AnalysisOutputError(
-              operation,
-              "Provider retained a malformed completed execution observation.",
-              { cause: verifiedPartial.error },
-            ),
-          );
+        }
       }
       return result;
     }
@@ -118,14 +111,7 @@ export class WebRuntimeService {
           if (evidence.ok) result.error.partialObservation = evidence.value;
           else if (result.error instanceof AnalysisCancelledError)
             return evidence;
-        } else if (result.error instanceof AnalysisCancelledError)
-          return err(
-            new AnalysisOutputError(
-              operation,
-              "Provider retained malformed completed event-listener data.",
-              { cause: verifiedPartial.error },
-            ),
-          );
+        }
       }
       return result;
     }
diff --git a/src/application/javascript/ElectronObservationService.test.ts b/src/application/javascript/ElectronObservationService.test.ts
index 0d055e1f09..bb4eee1233 100644
--- a/src/application/javascript/ElectronObservationService.test.ts
+++ b/src/application/javascript/ElectronObservationService.test.ts
@@ -5,6 +5,7 @@ import {
   AnalysisCancelledError,
   AnalysisOutputError,
 } from "../../domain/analysisErrorCore.js";
+import { projectAnalysisError } from "../../domain/analysisErrorProjection.js";
 import { ProviderCleanupError } from "../../domain/providerCleanupError.js";
 import { parseEvidence } from "../../domain/evidence.js";
 import {
@@ -244,3 +245,32 @@ it.each(["list", "inspect"] as const)(
     expect(providerCalls).toBe(0);
   },
 );
+
+it("keeps cancellation when the retained Electron inspection is incomplete", async () => {
+  const reason = { requested: "stop before page inspection completed" };
+  const partial = {
+    kind: "electron-page-observation",
+    inspection: { target_id: "electron-page" },
+    cleanup: "incomplete",
+  };
+  const failure = new AnalysisCancelledError("inspect_electron_page", {
+    cause: reason,
+    partialObservation: partial as never,
+  });
+  const provider: ElectronObservationPort = {
+    identity: () => identity,
+    listTargets: async () =>
+      err(new AnalysisCancelledError("list_electron_targets")),
+    inspectPage: async () => err(failure),
+  };
+  const result = await inspectElectronPage(provider, input);
+  expect(result.ok).toBe(false);
+  if (result.ok) throw new Error("Expected cancellation");
+  expect(result.error).toBe(failure);
+  expect(result.error.cause).toBe(reason);
+  expect(result.error.partialObservation).toBe(partial);
+  expect(projectAnalysisError(result.error)).toMatchObject({
+    code: "cancelled",
+    details: { partial_observation: partial },
+  });
+});
diff --git a/src/application/javascript/ElectronObservationService.ts b/src/application/javascript/ElectronObservationService.ts
index 67a0776cb4..bb748455b5 100644
--- a/src/application/javascript/ElectronObservationService.ts
+++ b/src/application/javascript/ElectronObservationService.ts
@@ -79,17 +79,7 @@ export const inspectElectronPage = async (
       partial.kind === "electron-page-observation"
     ) {
       const report = electronPageInspectionSchema.safeParse(partial.inspection);
-      if (!report.success) {
-        if (result.error instanceof AnalysisCancelledError)
-          return err(
-            new AnalysisOutputError(
-              "inspect_electron_page",
-              "Electron provider retained a malformed completed page inspection.",
-              { cause: report.error },
-            ),
-          );
-        return result;
-      }
+      if (!report.success) return result;
       const inspection = {
         ...report.data,
         limitations: [
diff --git a/src/application/javascript/JavaScriptRuntimeObservationService.test.ts b/src/application/javascript/JavaScriptRuntimeObservationService.test.ts
index b9351db166..8d83f01dc9 100644
--- a/src/application/javascript/JavaScriptRuntimeObservationService.test.ts
+++ b/src/application/javascript/JavaScriptRuntimeObservationService.test.ts
@@ -5,6 +5,7 @@ import {
   AnalysisCancelledError,
   AnalysisOutputError,
 } from "../../domain/analysisErrorCore.js";
+import { projectAnalysisError } from "../../domain/analysisErrorProjection.js";
 import { err, ok } from "../../domain/result.js";
 import { parseEvidence } from "../../domain/evidence.js";
 import type { JavaScriptRuntimeTargetList } from "../../domain/javascript/javascriptRuntimeObservation.js";
@@ -317,3 +318,32 @@ it.each(["list", "observe"] as const)(
     expect(providerCalls).toBe(0);
   },
 );
+
+it("keeps cancellation when the retained runtime observation is incomplete", async () => {
+  const reason = { requested: "stop before runtime observation completed" };
+  const partial = { runtime: "partial", scripts: [] };
+  const failure = new AnalysisCancelledError("observe_javascript_runtime", {
+    cause: reason,
+    partialObservation: partial as never,
+  });
+  const provider: JavaScriptRuntimeObservationPort = {
+    identity: () => ({ id: "test", name: "Test", version: "1" }),
+    listTargets: async () =>
+      err(new AnalysisCancelledError("list_javascript_runtime_targets")),
+    observe: async () => err(failure),
+  };
+  const result = await observeJavaScriptRuntime(provider, {
+    inspector_endpoint: "http://127.0.0.1:9229",
+    target_id: "target",
+    observation_ms: 0,
+  });
+  expect(result.ok).toBe(false);
+  if (result.ok) throw new Error("Expected cancellation");
+  expect(result.error).toBe(failure);
+  expect(result.error.cause).toBe(reason);
+  expect(result.error.partialObservation).toBe(partial);
+  expect(projectAnalysisError(result.error)).toMatchObject({
+    code: "cancelled",
+    details: { partial_observation: partial },
+  });
+});
diff --git a/src/application/javascript/JavaScriptRuntimeObservationService.ts b/src/application/javascript/JavaScriptRuntimeObservationService.ts
index 398995f139..4d8466a120 100644
--- a/src/application/javascript/JavaScriptRuntimeObservationService.ts
+++ b/src/application/javascript/JavaScriptRuntimeObservationService.ts
@@ -76,14 +76,6 @@ export const observeJavaScriptRuntime = async (
       !("kind" in partial)
     ) {
       const report = javascriptRuntimeObservationSchema.safeParse(partial);
-      if (!report.success && result.error instanceof AnalysisCancelledError)
-        return err(
-          new AnalysisOutputError(
-            "observe_javascript_runtime",
-            "Inspector retained a malformed completed runtime observation.",
-            { cause: report.error },
-          ),
-        );
       if (report.success)
         result.error.partialObservation =
           createJavaScriptRuntimeObservationEvidence(