diff --git a/docs/canvases/agent-bundle-walkthrough.canvas.tsx b/docs/canvases/agent-bundle-walkthrough.canvas.tsx
index 5bc27be66..557649336 100644
--- a/docs/canvases/agent-bundle-walkthrough.canvas.tsx
+++ b/docs/canvases/agent-bundle-walkthrough.canvas.tsx
@@ -403,8 +403,9 @@ export default function AgentBundleWalkthrough() {
           <Text as="span" weight="semibold"> inputSchema</Text>, and
           <Text as="span" weight="semibold"> resultSchema</Text> exports — there is no
           execute/render split (exporting either is the AB4811 error). Other
-          route kinds (events, CLI commands, skills) carry their own export
-          contracts.
+          route kinds (events, CLI commands) carry their own export
+          contracts; skills are Markdown documents parsed from frontmatter
+          unless the rendered SKILL.tsx form is used.
         </Text>
         <Grid columns="1fr 1fr" gap={12} align="start">
           <Card>
@@ -643,7 +644,7 @@ export default function AgentBundleWalkthrough() {
             n={5}
             title="Thin client prints the host-native response and exits 0"
             channel="wrapper → Claude · stdout"
-            note="Claude blocks the Write and surfaces the reason to the model. If the route had decided to allow it, the wrapper prints an explicit hookSpecificOutput.permissionDecision: 'allow' (optionally with updatedInput / additionalContext); a route that renders no decision prints nothing."
+            note="Claude blocks the Write and surfaces the reason to the model. On tool/before the wrapper always answers: an explicit hookSpecificOutput.permissionDecision ('allow' unless the route denied, optionally with updatedInput / additionalContext) — even when the route renders no decision. Silence is reserved for observation-only families such as session/end."
             payload={WIRE_STDOUT}
             last
           />
diff --git a/examples/audiobook-curator/src/evidence.ts b/examples/audiobook-curator/src/evidence.ts
index 1476da35c..4dab858ef 100644
--- a/examples/audiobook-curator/src/evidence.ts
+++ b/examples/audiobook-curator/src/evidence.ts
@@ -260,11 +260,13 @@ export const identifyAudibleSample = async (
   for (const candidate of selected) {
     const asin = String(candidate.asin ?? '');
     const region = String(candidate.region ?? 'us') as AudibleRegion;
+    const score = asRecord(candidate.evidence).score as JsonValue | undefined;
+    // Receipts are strict JSON; absent fields are omitted, never undefined.
     const base = {
-      asin: asin || undefined,
+      ...(asin === '' ? {} : { asin }),
       region,
-      score: asRecord(candidate.evidence).score as JsonValue | undefined,
-      title: candidate.title,
+      ...(score === undefined ? {} : { score }),
+      ...(candidate.title === undefined ? {} : { title: candidate.title }),
     };
     if (asin === '') {
       attempts.push({ ...base, reason: 'candidate has no ASIN', status: 'skipped' });
@@ -276,20 +278,27 @@ export const identifyAudibleSample = async (
         attempts: input.attempts,
         chunkSeconds: input.chunkSeconds,
         file: input.file,
+        // Staging follows the receipt's disk; without this, identification
+        // would stage beside source media the receipt was chosen to avoid.
+        ...(input.receipt === undefined ? {} : { receipt: input.receipt }),
         region,
         ...(typeof candidate.sample_url === 'string' ? { sampleUrl: candidate.sample_url } : {}),
         verbose: input.verbose,
       }, dependencies);
       const found = outcome.fingerprint.found === true;
+      const attemptTitle = candidate.title ?? outcome.audible.title;
       attempts.push({
         ...base,
         fingerprint: outcome.fingerprint,
-        sampleUrl: outcome.audible.sampleUrl,
+        ...(outcome.audible.sampleUrl === undefined ? {} : { sampleUrl: outcome.audible.sampleUrl }),
         status: found ? 'matched' : 'no-match',
-        title: candidate.title ?? outcome.audible.title,
+        ...(attemptTitle === undefined ? {} : { title: attemptTitle }),
       });
       if (found) {
-        identified ??= { asin, region, title: candidate.title ?? outcome.audible.title };
+        const title = candidate.title ?? outcome.audible.title;
+        // A titleless identification must not place an undefined (non-JSON)
+        // value into the durable receipt.
+        identified ??= { asin, region, ...(title === undefined ? {} : { title }) };
         if (input.all !== true) break;
       }
     } catch (error) {
diff --git a/examples/audiobook-curator/tests/evidence-parity.test.ts b/examples/audiobook-curator/tests/evidence-parity.test.ts
index f701963d8..ae9d252bf 100644
--- a/examples/audiobook-curator/tests/evidence-parity.test.ts
+++ b/examples/audiobook-curator/tests/evidence-parity.test.ts
@@ -168,4 +168,32 @@ describe('optional identity evidence parity', () => {
     expect(receipt).toMatchObject({ exitCode: 0, operation: 'whisper-identity', status: 'transcript-ready', usableWindows: 5 });
     expect(whisperCalls).toBe(5);
   });
+
+
+  it('stages acoustic-identify candidate work beside the receipt when one is requested', async () => {
+    const root = await mkdtemp(join(tmpdir(), 'curator-identify-receipt-'));
+    roots.push(root);
+    const file = join(root, 'library', 'book.m4b');
+    const receiptPath = join(root, 'receipts', 'identify.json');
+    await mkdir(dirname(file), { recursive: true });
+    await writeFile(file, 'book');
+    const sampleDirs: string[] = [];
+    const matcher: AcousticMatcher = async (_source, sample) => {
+      sampleDirs.push(dirname(sample));
+      return { found: true };
+    };
+    const http: CuratorHttpClient = async (url, options) => {
+      if (options?.binary === true) return Buffer.from(url);
+      throw new Error('unexpected product request');
+    };
+    await identifyAudibleSample({
+      candidates: [{ asin: 'MATCH', evidence: { score: 90 }, region: 'us', sample_url: 'https://samples/match.mp3' }],
+      candidatesReport: join(root, 'candidates.json'),
+      file,
+      receipt: receiptPath,
+      top: 1,
+    }, { http, matcher });
+    expect(sampleDirs).toHaveLength(1);
+    expect(sampleDirs[0]!.startsWith(join(dirname(receiptPath), '.audiobook-curator-acoustic-'))).toBe(true);
+  });
 });