diff --git a/src/application/BrowserObservationService.test.ts b/src/application/BrowserObservationService.test.ts
index 6b6ed4fbc2..1cd7eb2609 100644
--- a/src/application/BrowserObservationService.test.ts
+++ b/src/application/BrowserObservationService.test.ts
@@ -11,6 +11,7 @@ import {
   AnalysisCancelledError,
   AnalysisOutputError,
 } from "../domain/analysisErrorCore.js";
+import { resolvedAnalysisError } from "../domain/analysisErrorBase.js";
 import { projectAnalysisError } from "../domain/analysisErrorProjection.js";
 import {
   expectDroppedPartial,
@@ -150,6 +151,49 @@ it("converts a raw page inspection retained after browser cleanup failure", asyn
   }
 });
 
+it.each([true, false])(
+  "promotes cleanup primary facts once when wrapper retains them: %s",
+  async (wrapperRetainsFacts) => {
+    const inspection = passiveNetworkCapture();
+    const primary = new AnalysisCancelledError("inspect_web_page", {
+      partialObservation: inspection,
+    });
+    const failure = new BrowserObservationError(
+      "inspect_web_page",
+      "cleanup_failed",
+      {
+        cleanupPrimary: primary,
+        cleanup: {
+          reason: "target detach failed",
+          resources: ["browser target"],
+        },
+        ...(wrapperRetainsFacts ? { partialObservation: inspection } : {}),
+      },
+    );
+    const browser = {
+      ...provider(async () => ok(report)),
+      inspectPage: async () => err(failure),
+    } as unknown as BrowserObservationPort;
+    const result = await inspectWebPage(browser, pageInput());
+    expect(result.ok).toBe(false);
+    expect(parseEvidence(primary.partialObservation)).toMatchObject({
+      operation: "inspect_web_page",
+      normalized_result: inspection,
+    });
+    if (wrapperRetainsFacts)
+      expect(failure.partialObservation).toBe(primary.partialObservation);
+    failure.resolveCleanup();
+    expect(resolvedAnalysisError(failure)).toBe(primary);
+    expect(
+      parseEvidence(
+        projectAnalysisError(resolvedAnalysisError(failure)).details?.[
+          "partial_observation"
+        ],
+      ),
+    ).toEqual(primary.partialObservation);
+  },
+);
+
 it("retains captured page Evidence when bundle analysis fails after capture", async () => {
   const inspection = passiveNetworkCapture();
   const failure = new BrowserObservationError(
diff --git a/src/application/BrowserObservationService.ts b/src/application/BrowserObservationService.ts
index 5508a9186e..2d61e6e649 100644
--- a/src/application/BrowserObservationService.ts
+++ b/src/application/BrowserObservationService.ts
@@ -288,44 +288,71 @@ const retainBrowserObservation = (
   provider: BrowserObservationPort,
   errorOperation: "inspect_web_page" | "analyze_web_bundle",
 ): Result<Evidence, AnalysisError> => {
-  const partial = error.partialObservation;
+  const seen = new Set<AnalysisError>();
+  const promoted = new Map<object, Evidence>();
+  let current: AnalysisError | undefined = error;
+  while (current !== undefined && !seen.has(current)) {
+    seen.add(current);
+    const partial = current.partialObservation;
+    if (partial !== undefined) {
+      const evidence =
+        promoted.get(partial) ??
+        promoteBrowserObservation(partial, input, provider, errorOperation);
+      if (evidence !== undefined) {
+        promoted.set(partial, evidence);
+        current.partialObservation = evidence;
+      }
+    }
+    current = current.cleanupPrimary;
+  }
+  return err(
+    keepIncompleteObservation(
+      error,
+      errorOperation,
+      NON_JSON_BROWSER_OBSERVATION,
+    ),
+  );
+};
+
+/** Each cleanup owner can become the selected error after cleanup succeeds. */
+const promoteBrowserObservation = (
+  partial: NonNullable<AnalysisError["partialObservation"]>,
+  input: InspectWebPageInput | AnalyzeWebBundleInput,
+  provider: BrowserObservationPort,
+  errorOperation: "inspect_web_page" | "analyze_web_bundle",
+): Evidence | undefined => {
   if (
     errorOperation === "analyze_web_bundle" &&
-    partial !== undefined &&
     "kind" in partial &&
     partial.kind === "web-bundle-acquisition"
   ) {
     const acquisition =
       webBundleAcquisitionPartialObservationSchema.safeParse(partial);
     if (acquisition.success) {
-      error.partialObservation = createBrowserEvidence(
+      return createBrowserEvidence(
         "analyze_web_bundle",
         input,
         acquisition.data,
         provider.identity(),
       );
-      return err(error);
     }
   }
   if (
     errorOperation === "analyze_web_bundle" &&
-    partial !== undefined &&
     !("evidence_id" in partial) &&
     "observations" in partial &&
     "capture" in partial
   ) {
     const bundle = webBundleAnalysisSchema.safeParse(partial);
     if (bundle.success) {
-      error.partialObservation = createBrowserEvidence(
+      return createBrowserEvidence(
         "analyze_web_bundle",
         input,
         bundle.data,
         provider.identity(),
       );
-      return err(error);
     }
   } else if (
-    partial !== undefined &&
     !("evidence_id" in partial) &&
     "target" in partial &&
     "network" in partial &&
@@ -337,20 +364,13 @@ const retainBrowserObservation = (
         "fetch_source_maps" in input
           ? (({ fetch_source_maps: _fetchSourceMaps, ...page }) => page)(input)
           : input;
-      error.partialObservation = createBrowserEvidence(
+      return createBrowserEvidence(
         "inspect_web_page",
         pageInput,
         inspection.data,
         provider.identity(),
       );
-      return err(error);
     }
   }
-  return err(
-    keepIncompleteObservation(
-      error,
-      errorOperation,
-      NON_JSON_BROWSER_OBSERVATION,
-    ),
-  );
+  return undefined;
 };