diff --git a/tests/e2e/fixtures/native-ingestion-blocked-stop-authority.ts b/tests/e2e/fixtures/native-ingestion-blocked-stop-authority.ts
new file mode 100644
index 00000000000..7d29183bc10
--- /dev/null
+++ b/tests/e2e/fixtures/native-ingestion-blocked-stop-authority.ts
@@ -0,0 +1,131 @@
+// Bounded verbatim copy of the H5c authority/process proof, e431ec63; frozen measured source stays unchanged.
+import { createHash } from "node:crypto";
+import { createRequire } from "node:module";
+import { lstat, readFile, readdir, realpath } from "node:fs/promises";
+import { hostname } from "node:os";
+import path from "node:path";
+import { expect } from "@playwright/test";
+export async function runtimeAuthority(input: {
+  appRoot: string; companyId: string; environmentId: string; issueIds: string[]; transport: "local" | "sandbox-remote";
+  afterStop?: boolean; recordedFailureRunIds?: string[];
+}) {
+  const configuration = process.env.PAPERCLIP_E2E_SERVER_CONFIG;
+  if (!configuration) throw new Error("Missing owned server configuration");
+  const config = JSON.parse(await readFile(configuration, "utf8"));
+  expect(config.database.mode).toBe("embedded-postgres");
+  const dataDirectory = await realpath(config.database.embeddedPostgresDataDir);
+  const ownedHome = await realpath(path.resolve(path.dirname(configuration), "../.."));
+  expect(dataDirectory.startsWith(`${ownedHome}${path.sep}`)).toBe(true);
+  const owner = (await readFile(path.join(dataDirectory, "postmaster.pid"), "utf8")).split(/\r?\n/);
+  expect(await realpath(owner[1])).toBe(dataDirectory);
+  const port = Number(owner[3]);
+  expect(Number.isSafeInteger(port) && port > 0 && port <= 65535).toBe(true);
+  const require = createRequire(path.join(input.appRoot, "packages/db/package.json"));
+  const postgres = require("postgres");
+  const sql = postgres({ host: "127.0.0.1", port, database: "paperclip", username: "paperclip", password: "paperclip",
+    max: 1, connect_timeout: 10, connection: { application_name: "native_ingestion_remote_authority_proof" } });
+  let proof;
+  try {
+    proof = await sql.begin("isolation level repeatable read read only", async (tx: any) => {
+      const settings = await tx`select current_setting('transaction_read_only') as read_only,
+        current_setting('transaction_isolation') as isolation`;
+      expect(settings[0].read_only).toBe("on");
+      expect(settings[0].isolation).toBe("repeatable read");
+      if (input.recordedFailureRunIds) {
+        const queryStartedAtMs = Date.now();
+        const rows = await tx`select r.id as run_id, r.company_id, r.agent_id, r.runtime_mode, r.status, r.native_phase,
+          r.error_code as current_error_code, r.error is not null as current_has_error,
+          jsonb_typeof(r.result_json->'recoveredExecutionFailure') as recovered_type,
+          r.result_json->'recoveredExecutionFailure'->>'schema' as recovered_schema,
+          r.result_json->'recoveredExecutionFailure'->>'errorCode' as recovered_error_code,
+          r.result_json->'recoveredExecutionFailure'->>'observedAt' as recovered_observed_at,
+          f.attempt as finalization_attempt
+          from heartbeat_runs r left join native_run_finalizations f on f.run_id = r.id and f.company_id = r.company_id
+          where r.company_id = ${input.companyId} and r.id = any(${input.recordedFailureRunIds}::uuid[])`;
+        return { kind: "recorded-run-failure-codes", queryStartedAtMs, checkedAtMs: Date.now(),
+          transaction: "READ ONLY REPEATABLE READ", observedReadOnly: settings[0].read_only,
+          observedIsolation: settings[0].isolation, rows };
+      }
+      const rows = await tx`select r.id as run_id, r.company_id, r.agent_id, r.native_issue_id as issue_id, r.runtime_mode,
+        r.native_session_id, r.runner_instance_id, r.status, r.process_pid, r.process_group_id, r.process_started_at,
+        r.runner_profile_json->'nativeExecutionInput'->'binding'->>'executionWorkspaceId' as admitted_execution_workspace_id,
+        r.result_json->'nativeCancellation'->>'dispatchState' as cancellation_dispatch_state,
+        i.seq as process_identity_seq, i.payload as process_identity, i.source_event_id as process_identity_source_event_id,
+        s.seq as process_stopped_seq, s.payload as process_stopped, s.source_event_id as process_stopped_source_event_id,
+        l.id as lease_id, l.environment_id, l.provider, l.provider_lease_id,
+        c.part as checkpoint_part, octet_length(c.material::text) as checkpoint_header_bytes
+        from heartbeat_runs r
+        join environment_leases l on l.heartbeat_run_id = r.id and l.company_id = r.company_id
+        left join native_runner_checkpoints c on c.run_id = r.id and c.company_id = r.company_id
+          and c.issue_id = r.native_issue_id and c.part = 'header'
+        left join lateral (select seq, payload, source_event_id from heartbeat_run_events e where e.run_id = r.id
+          and e.company_id = r.company_id and e.event_type = 'native.process_identity_recorded'
+          and e.source_event_id is null order by seq desc limit 1) i on true
+        left join lateral (select seq, payload, source_event_id from heartbeat_run_events e where e.run_id = r.id
+          and e.company_id = r.company_id and e.event_type = 'native.local_process_stopped'
+          and e.source_event_id is null order by seq desc limit 1) s on true
+        where r.company_id = ${input.companyId} and r.native_issue_id = any(${input.issueIds}::uuid[])`;
+      expect(rows).toHaveLength(input.issueIds.length);
+      expect(new Set(rows.map((row: any) => row.issue_id)).size).toBe(input.issueIds.length);
+      for (const row of rows) {
+        expect(row.company_id).toBe(input.companyId);
+        expect(row.runtime_mode).toBe("native");
+        expect(row.environment_id).toBe(input.environmentId);
+        if (input.transport === "sandbox-remote") {
+          expect(row.provider).toBe("fake-plugin");
+          expect(row.provider_lease_id).toMatch(/^fake-plugin:\/\//);
+          expect(row.checkpoint_part).toBe("header");
+          expect(Number(row.checkpoint_header_bytes)).toBeGreaterThan(0);
+        } else {
+          expect(row.provider).toBe("local"); expect(row.provider_lease_id).toBeNull();
+          expect(row.checkpoint_part, "Local raw transport keeps its existing host-file journal authority").toBeNull();
+          expect(row.process_identity?.targetKind).toBe("local"); expect(row.process_identity?.hostname).toBe(hostname());
+          expect(row.process_identity_source_event_id).toBeNull();
+          expect(BigInt(String(row.process_identity_seq))).toBeGreaterThan(0n);
+          expect(row.admitted_execution_workspace_id).toMatch(/^[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$/i);
+          if (row.process_started_at) expect(row.process_identity.processStartedAt).toBe(new Date(row.process_started_at).toISOString());
+        }
+      }
+      return { kind: input.transport === "local" ? "host-file-journal" : "database-controller-checkpoint",
+        checkedBeforeMeasuredEpoch: !input.afterStop, checkedAtMs: Date.now(), transaction: "READ ONLY REPEATABLE READ",
+        observedReadOnly: settings[0].read_only, observedIsolation: settings[0].isolation, rows };
+    });
+  } finally { await sql.end({ timeout: 5 }); }
+  const connectionClosedAtMs = Date.now();
+  let localJournal;
+  if (input.transport === "local" && !input.afterStop && !input.recordedFailureRunIds) {
+    expect(input.issueIds).toHaveLength(1);
+    const base = await realpath(path.join(path.dirname(configuration), "runtime/paperclip-runner/durable-sessions"));
+    expect(base.startsWith(`${ownedHome}${path.sep}`)).toBe(true);
+    const directories = (await readdir(base, { withFileTypes: true })).filter(entry => entry.isDirectory() && /^[a-f0-9]{64}$/.test(entry.name));
+    expect(directories.length, "Bound the owned fixture journal metadata search").toBeLessThanOrEqual(256);
+    for (const directory of directories) {
+      const file = path.join(base, directory.name, "control-plane/control-plane-state.json");
+      const metadata = await lstat(file).catch((error: NodeJS.ErrnoException) => {
+        if (error.code === "ENOENT") return null; throw error;
+      });
+      if (!metadata) continue;
+      expect(metadata.isFile() && !metadata.isSymbolicLink() && metadata.size <= 16 * 1024 * 1024).toBe(true);
+      expect((await realpath(file)).startsWith(`${base}${path.sep}`)).toBe(true);
+      const bytes = await readFile(file), state = JSON.parse(bytes.toString("utf8"));
+      if (state.identity?.runId !== proof!.rows[0].run_id) continue;
+      expect(localJournal, "Exactly one owned local journal must match the actual run").toBeUndefined();
+      expect(state.schema).toBe("paperclip.runner.durable.control-plane-state.v1");
+      expect(state.checkpointEventPolicy).not.toBe("control-v1");
+      expect(state.identity.runnerInstanceId).toBe(proof!.rows[0].runner_instance_id);
+      expect(state.identity.normalizedSessionId).toBe(proof!.rows[0].native_session_id);
+      expect(state.identity.environmentLeaseId).toBe(proof!.rows[0].admitted_execution_workspace_id);
+      localJournal = { file, sha256: createHash("sha256").update(bytes).digest("hex"), bytes: bytes.length,
+        schema: state.schema, identity: Object.fromEntries(["runnerInstanceId", "environmentLeaseId", "runId", "normalizedSessionId", "turnId", "itemId"]
+          .map(key => [key, state.identity[key]])), checkpointEventPolicy: state.checkpointEventPolicy, checkedAtMs: Date.now() };
+    }
+    expect(localJournal, "Missing actual owned local raw journal").toBeTruthy();
+  }
+  return { ...proof, connectionClosedAtMs, localJournal };
+}
+
+export const processAbsent = (pid: number) => {
+  expect(Number.isSafeInteger(pid) && Math.abs(pid) > 1).toBe(true);
+  try { process.kill(pid, 0); return false; }
+  catch (error) { if ((error as NodeJS.ErrnoException).code === "ESRCH") return true; throw error; }
+};
diff --git a/tests/e2e/fixtures/native-ingestion-blocked-stop-clock.ts b/tests/e2e/fixtures/native-ingestion-blocked-stop-clock.ts
new file mode 100644
index 00000000000..918ecd8a5fa
--- /dev/null
+++ b/tests/e2e/fixtures/native-ingestion-blocked-stop-clock.ts
@@ -0,0 +1,127 @@
+// Gate and two-frame observer copied from frozen H5c e431ec63, narrowed to one owned participant.
+import { createServer, type ServerResponse } from "node:http";
+import { expect, type Page } from "@playwright/test";
+export type SeenMarker = { markerCode: string; index: number; visibleMs: number };
+export type Emission = { nonce: string; markerCode: string; index: number; intendedMs: number; emittedMs: number; receivedAtMs: number };
+type ClockStream = { nonce: string; markerCode: string; opened: boolean; hello: boolean; ended: boolean; aborted: boolean;
+  partialBytes: number; records: Map<number, Emission>; error?: string; expectedLauncher: "host-local" | "staged-remote";
+  launcher?: string; providerPid?: number; providerReadyAtMs?: number; clockHelloAtMs?: number; readinessObservedAtMs?: number };
+type ClockCase = { events: number; intervalMs: number; epochMs?: number; streams: Map<string, ClockStream>; errors: string[] };
+export async function openClock(page: Page) {
+  const pending = new Map<string, Map<string, ServerResponse>>();
+  const clocks = new Map<string, ClockCase>();
+  let markerCounter = 0;
+  const nextMarkerCode = () => {
+    expect(markerCounter).toBeLessThan(36 ** 2);
+    return (markerCounter++).toString(36).padStart(2, "0");
+  };
+  const gate = createServer((req, res) => {
+    const url = new URL(req.url!, "http://127.0.0.1");
+    const route = url.pathname.match(/^\/native-ingestion-gate\/([a-f0-9]{32})(\/clock)?$/);
+    const key = route?.[1], participant = url.searchParams.get("participant");
+    const state = key ? clocks.get(key) : undefined;
+    const stream = participant ? state?.streams.get(participant) : undefined;
+    if (!key || !participant || !state || !stream) { res.writeHead(404).end(); return; }
+    if (!route?.[2] && req.method === "GET") {
+      if (pending.get(key)!.has(participant)) { res.writeHead(409).end(); return; }
+      stream.providerReadyAtMs = Date.now();
+      pending.get(key)!.set(participant, res);
+      res.on("close", () => pending.get(key)?.delete(participant));
+      return;
+    }
+    if (!route?.[2] || req.method !== "POST" || stream.opened) { res.writeHead(409).end(); return; }
+    stream.opened = true;
+    let buffered = "";
+    req.setEncoding("utf8");
+    const fail = (message: string) => {
+      stream.error = message; state.errors.push(`${participant}: ${message}`);
+      if (!res.writableEnded) res.writeHead(400).end();
+    };
+    const line = (text: string) => {
+      const value = JSON.parse(text);
+      if (value.nonce !== participant || value.markerCode !== stream.markerCode) throw new Error("Clock identity mismatch");
+      if (!stream.hello) {
+        if (value.type !== "hello" || value.events !== state.events || value.intervalMs !== state.intervalMs
+          || value.launcher !== stream.expectedLauncher || !Number.isSafeInteger(value.providerPid) || value.providerPid <= 1
+          || Object.keys(value).sort().join(",") !== "events,intervalMs,launcher,markerCode,nonce,providerPid,type") throw new Error("Clock hello mismatch");
+        stream.launcher = value.launcher; stream.providerPid = value.providerPid;
+        stream.hello = true; stream.clockHelloAtMs = Date.now(); return;
+      }
+      if (value.type !== "emission" || !Number.isSafeInteger(value.index) || value.index < 0 || value.index >= state.events
+        || !Number.isSafeInteger(value.intendedMs) || !Number.isSafeInteger(value.emittedMs) || value.emittedMs <= 0
+        || value.intendedMs !== state.epochMs! + value.index * state.intervalMs) throw new Error("Invalid original emission clock");
+      if (stream.records.has(value.index)) throw new Error("Duplicate or conflicting original emission clock");
+      stream.records.set(value.index, { nonce: participant, markerCode: stream.markerCode, index: value.index,
+        intendedMs: value.intendedMs, emittedMs: value.emittedMs, receivedAtMs: Date.now() });
+    };
+    req.on("data", (chunk: string) => {
+      if (stream.error) return;
+      try {
+        buffered += chunk;
+        for (;;) {
+          const end = buffered.indexOf("\n"); if (end < 0) break;
+          const text = buffered.slice(0, end); buffered = buffered.slice(end + 1);
+          if (text.length > 1024) throw new Error("Clock record exceeds bounded metadata size");
+          if (text) line(text);
+        }
+        if (buffered.length > 1024) throw new Error("Clock record exceeds bounded metadata size");
+      } catch (error) { fail(String(error)); }
+    });
+    req.on("end", () => {
+      stream.ended = true; stream.partialBytes = Buffer.byteLength(buffered);
+      if (buffered.length) fail("Clock stream ended with a partial record");
+      if (!stream.error && !res.writableEnded) res.writeHead(200).end();
+    });
+    req.on("aborted", () => { stream.aborted = true; stream.partialBytes = Buffer.byteLength(buffered); });
+    req.on("error", error => { if (!stream.aborted) fail(String(error)); });
+  });
+  await new Promise<void>(resolve => gate.listen(0, "127.0.0.1", resolve));
+  const address = gate.address();
+  if (!address || typeof address === "string") throw new Error("Local ingestion gate failed");
+  const base = `http://127.0.0.1:${address.port}/native-ingestion-gate/`;
+  await page.addInitScript(() => {
+    const seen = new Set<string>(), visible: SeenMarker[] = [];
+    Object.assign(window, { nativeIngestionVisible: visible });
+    let scheduled = false, dirty = false;
+    const snapshot = () => {
+      const text = document.body?.innerText ?? "";
+      const pattern = /\[([a-z0-9]{2})([a-z0-9]{1,3})\]/g;
+      const entries: Omit<SeenMarker, "visibleMs">[] = [];
+      for (const match of text.matchAll(pattern)) {
+        const index = Number.parseInt(match[2], 36);
+        const key = `${match[1]}:${index}`;
+        if (seen.has(key)) continue;
+        entries.push({ markerCode: match[1], index });
+      }
+      return entries;
+    };
+    const schedule = () => {
+      dirty = true;
+      if (scheduled) return;
+      scheduled = true;
+      requestAnimationFrame(() => {
+        dirty = false;
+        const entries = snapshot();
+        requestAnimationFrame(() => {
+          // Only stamp the previous frame's snapshot. A token inserted
+          // between frames has not had this snapshot's paint opportunity.
+          const visibleMs = Date.now();
+          for (const entry of entries) {
+            const key = `${entry.markerCode}:${entry.index}`;
+            if (seen.has(key)) continue;
+            seen.add(key); visible.push({ ...entry, visibleMs });
+          }
+          scheduled = false;
+          if (dirty) schedule();
+        });
+      });
+    };
+    const install = () => {
+      new MutationObserver(schedule).observe(document.body, { subtree: true, childList: true, characterData: true });
+      schedule();
+    };
+    if (document.body) install(); else addEventListener("DOMContentLoaded", install, { once: true });
+  });
+
+  return { pending, clocks, nextMarkerCode, base, gate };
+}
diff --git a/tests/e2e/fixtures/native-ingestion-blocked-stop-db.ts b/tests/e2e/fixtures/native-ingestion-blocked-stop-db.ts
new file mode 100644
index 00000000000..acb6a275c3b
--- /dev/null
+++ b/tests/e2e/fixtures/native-ingestion-blocked-stop-db.ts
@@ -0,0 +1,43 @@
+import { createRequire } from "node:module";
+import { readFile, realpath } from "node:fs/promises";
+import path from "node:path";
+import { expect } from "@playwright/test";
+
+export async function ownedDatabase(appRoot: string, name: string) {
+  const configuration = process.env.PAPERCLIP_E2E_SERVER_CONFIG;
+  if (!configuration) throw new Error("Missing disposable application configuration");
+  const config = JSON.parse(await readFile(configuration, "utf8"));
+  expect(config.database.mode).toBe("embedded-postgres");
+  const home = await realpath(path.resolve(path.dirname(configuration), "../.."));
+  const directory = await realpath(config.database.embeddedPostgresDataDir);
+  expect(directory.startsWith(`${home}${path.sep}`)).toBe(true);
+  const owner = (await readFile(path.join(directory, "postmaster.pid"), "utf8")).split(/\r?\n/);
+  expect(await realpath(owner[1])).toBe(directory);
+  const port = Number(owner[3]);
+  expect(Number.isSafeInteger(port) && port > 0 && port <= 65535).toBe(true);
+  const postgres = createRequire(path.join(appRoot, "packages/db/package.json"))("postgres");
+  return postgres({ host: "127.0.0.1", port, database: "paperclip", username: "paperclip", password: "paperclip",
+    max: 1, connect_timeout: 10, connection: { application_name: name } });
+}
+export async function cancellationSnapshot(sql: any, companyId: string, runId: string) {
+  const startedAtMs = Date.now();
+  const rows = await sql`select id as run_id, company_id, native_issue_id as issue_id, status,
+    result_json->'nativeCancellation' as intent,
+    result_json->'executionCancellation' as shared_execution_cancellation,
+    result_json->'cancellation' as run_cancellation,
+    (select jsonb_build_object('id', d.id, 'companyId', d.company_id, 'runId', d.run_id, 'issueId', d.issue_id,
+      'reasonCode', d.reason_code) from status_decisions d where d.company_id = r.company_id and d.run_id = r.id
+      and d.issue_id = r.native_issue_id and d.id::text = r.result_json->'nativeCancellation'->>'decisionId') as shared_decision,
+    (select coalesce(jsonb_agg(jsonb_build_object('id', a.id, 'action', a.action, 'details', a.details)), '[]'::jsonb)
+      from activity_log a where a.company_id = r.company_id and a.run_id = r.id
+      and a.action in ('native.cancellation_intent_recorded', 'native.cancellation_dispatch_acknowledged')) as audits
+    from heartbeat_runs r where r.company_id = ${companyId} and r.id = ${runId}`;
+  expect(rows).toHaveLength(1);
+  return { ...rows[0], queryStartedAtMs: startedAtMs, observedAtMs: Date.now() };
+}
+export async function blockers(sql: any, holderPid: number) {
+  return sql`select pid, application_name, state, wait_event_type, wait_event, query, query_start,
+    pg_blocking_pids(pid) as blocking_pids from pg_stat_activity
+    where datname = current_database() and pid <> pg_backend_pid()
+    and ${holderPid} = any(pg_blocking_pids(pid))`;
+}
diff --git a/tests/e2e/fixtures/native-ingestion-blocked-stop-protocol.mjs b/tests/e2e/fixtures/native-ingestion-blocked-stop-protocol.mjs
new file mode 100644
index 00000000000..cb4e126a7c0
--- /dev/null
+++ b/tests/e2e/fixtures/native-ingestion-blocked-stop-protocol.mjs
@@ -0,0 +1,303 @@
+import assert from 'node:assert/strict';
+import { createHash } from 'node:crypto';
+export const PROTOCOL = 'blocked-stop-history-v1';
+export const WORKLOAD = Object.freeze({ prelude: 1000, events: 256, intervalMs: 100, visibleBeforeLock: 3,
+  heldAfterActualRequestMs: 1000, pollIntervalMs: 50, readinessMs: 300000, streamMs: 120000,
+  terminalMs: 180000, acknowledgementAfterSettlementMs: 30000, leaseAfterSettlementMs: 30000, invocationMs: 900000 });
+export const WORKLOAD_SHA256 = createHash('sha256').update(JSON.stringify(WORKLOAD)).digest('hex');
+export const METRICS = ['actionToAckMs', 'releaseAckToAbsenceMs', 'releaseAckToAckMs'];
+export function isAppendLockQuery(query) {
+  // Shared B0/B1/B2 projection prefix, unlike cancellation's full-row SELECT.
+  const sql = String(query).replace(/\s+/g, ' ').trim();
+  return /^select "company_id", "agent_id"(?:,| from)/i.test(sql)
+    && / from "heartbeat_runs" where "heartbeat_runs"\."id" = \$\d+.* for update/i.test(sql);
+}
+export function assertHeldSample(sample, holderPid) {
+  assert.equal(sample.httpPending, true, 'Stop HTTP must remain pending while its durable barrier is locked');
+  assert.equal(sample.intent, null, 'No committed intent before releasing the run lock');
+  assert.deepEqual(sample.auditIds, [], 'No committed cancellation audit before releasing the run lock');
+  assert.equal(sample.processesAlive, true, 'No physical provider Stop before the durable intent barrier');
+  assert.equal(sample.clockOpen, true, 'The unchanged provider fixture closes its clock on turn/interrupt');
+  assert(sample.blockers.some(row => row.blocking_pids.includes(holderPid)), 'Missing independent PostgreSQL blocker');
+}
+export function assertIntentAudit(row) {
+  const intent = row.intent;
+  assert.equal(intent?.schema, 'paperclip.native-cancellation.v1');
+  assert.equal(intent.companyId, row.company_id); assert.equal(intent.runId, row.run_id);
+  assert.equal(intent.issueId, row.issue_id);
+  assert.equal(intent.scope, 'run'); assert.equal(intent.reasonCode, 'cancellation_run_only');
+  if (intent.decisionId != null) {
+    assert.equal(row.shared_decision?.id, intent.decisionId);
+    assert.equal(row.shared_decision.companyId, row.company_id); assert.equal(row.shared_decision.runId, row.run_id);
+    assert.equal(row.shared_decision.issueId, row.issue_id);
+  }
+  assert(row.audits.some(a => a.id === intent.intentAuditId && a.action === 'native.cancellation_intent_recorded'
+    && a.details?.intentId === intent.intentId), 'Intent must match its committed own audit');
+  if (intent.dispatchState === 'acknowledged') {
+    assert.equal(intent.dispatched, true);
+    assert(row.audits.some(a => a.id === intent.acknowledgementAuditId
+      && a.action === 'native.cancellation_dispatch_acknowledged' && a.details?.intentId === intent.intentId
+      && a.details.intentAuditId === intent.intentAuditId && a.details.dispatched === true
+      && (a.details.decisionId ?? null) === (intent.decisionId ?? null)), 'ACK must match its own committed audit and decision');
+  }
+}
+export function metrics(evidence) {
+  assert.equal(evidence.protocol, PROTOCOL); assert.equal(evidence.workloadSha256, WORKLOAD_SHA256);
+  assert.equal(evidence.complete, true); assert.equal(evidence.cleanup?.complete, true);
+  const t = evidence.timing;
+  for (const k of ['actionAtMs', 'requestAtMs', 'releaseRequestedAtMs', 'releaseCommitAckAtMs', 'absenceObservedAtMs', 'ackObservedAtMs'])
+    assert(Number.isSafeInteger(t[k]) && t[k] > 0, `Missing ${k}`);
+  assert(t.actionAtMs <= t.requestAtMs); assert(t.requestAtMs + WORKLOAD.heldAfterActualRequestMs <= t.releaseRequestedAtMs);
+  assert(t.releaseRequestedAtMs <= t.releaseCommitAckAtMs); assert(t.releaseCommitAckAtMs <= t.absenceObservedAtMs);
+  assert(t.releaseCommitAckAtMs <= t.ackObservedAtMs);
+  return { actionToAckMs: t.ackObservedAtMs - t.actionAtMs,
+    releaseAckToAbsenceMs: t.absenceObservedAtMs - t.releaseCommitAckAtMs,
+    releaseAckToAckMs: t.ackObservedAtMs - t.releaseCommitAckAtMs,
+    releaseRequestToAbsenceMs: t.absenceObservedAtMs - t.releaseRequestedAtMs,
+    releaseRequestToAckMs: t.ackObservedAtMs - t.releaseRequestedAtMs };
+}
+export function registration() {
+  const stages = [['b0-aa','b0','b0'], ['b1-aa','b1','b1'], ['b0-b1','b0','b1'], ['b1-b2','b1','b2'], ['b0-b2','b0','b2']];
+  return stages.flatMap(([stage,a,b]) => Array.from({ length: 5 }, (_, pair) => (pair % 2 ? [b,a] : [a,b])
+    .map((variant, index) => ({ stage, pair: pair + 1, index, variant, role: pair % 2 ? (index ? 'baseline' : 'candidate') : (index ? 'candidate' : 'baseline') })))).flat();
+}
+const median = values => {
+  assert(values.length > 0);
+  const sorted = [...values].sort((a,b) => a-b), middle = Math.floor(sorted.length / 2);
+  return sorted.length % 2 ? sorted[middle] : (sorted[middle - 1] + sorted[middle]) / 2;
+};
+const spread = values => ({ minimumMs: Math.min(...values), maximumMs: Math.max(...values),
+  spreadMs: Math.max(...values) - Math.min(...values) });
+const hashReport = evidence => createHash('sha256').update(JSON.stringify(evidence)).digest('hex');
+export const PRECISION_RULE = Object.freeze({ schema: 'blocked-stop-precision-v1',
+  pollIntervalMs: WORKLOAD.pollIntervalMs, floorMs: 2 * WORKLOAD.pollIntervalMs, pooledMedianFraction: 0.10,
+  pairedRule: 'maximum absolute difference <= budget', driftRule: 'absolute first-five vs last-five chronological median drift <= budget',
+  bracketRule: 'each observer bracket <= corresponding metric budget', unsuitableRule: 'retain all ten arms; no noise freeze or replacement',
+  scope: 'Measurement repeatability; not a product Stop deadline' });
+export const PRECISION_RULE_SHA256 = createHash('sha256').update(JSON.stringify(PRECISION_RULE)).digest('hex');
+export function observerBrackets(evidence) {
+  const t = evidence.timing, origin = t.releaseCommitAckAtMs;
+  const samples = evidence.observerSamples;
+  assert(Array.isArray(samples), 'Missing raw observer query/check samples');
+  const result = {};
+  for (const [kind, timestamp, negativeTimestamp] of [
+    ['ack-query', 'ackObservedAtMs', 'lastAckNotObservedAtMs'],
+    ['process-check', 'absenceObservedAtMs', 'lastProcessesPresentAtMs']]) {
+    const rows = samples.filter(row => row.kind === kind);
+    assert(rows.length > 0, `Missing ${kind} observer samples`);
+    let priorEnd = origin;
+    for (const [index,row] of rows.entries()) {
+      assert(Number.isSafeInteger(row.startedAtMs) && Number.isSafeInteger(row.completedAtMs));
+      assert(row.startedAtMs >= priorEnd && row.completedAtMs >= row.startedAtMs);
+      assert.equal(row.durationMs, row.completedAtMs - row.startedAtMs);
+      assert.equal(row.value, index === rows.length - 1, 'Retain every negative sample through the first successful observation');
+      priorEnd = row.completedAtMs;
+    }
+    const success = rows.at(-1), negative = rows.at(-2);
+    assert.equal(t[timestamp], success.completedAtMs);
+    if (negative) assert.equal(t[negativeTimestamp], negative.completedAtMs);
+    else assert(t[negativeTimestamp] === undefined, 'A negative timestamp needs its raw query/check sample');
+    // A negative query can read its snapshot at any point during execution;
+    // use its start as the conservative lower boundary and retain both ends.
+    const lowerAtMs = negative?.startedAtMs ?? origin;
+    result[kind] = { lowerAtMs, upperAtMs: success.completedAtMs,
+      widthMs: success.completedAtMs - lowerAtMs, lowerKind: negative ? 'last-negative-query-or-check-start' : 'release-COMMIT-ACK',
+      successfulStartedAtMs: success.startedAtMs, successfulDurationMs: success.durationMs,
+      ...(negative ? { negativeStartedAtMs: negative.startedAtMs, negativeCompletedAtMs: negative.completedAtMs,
+        negativeDurationMs: negative.durationMs } : {}), sampleCount: rows.length };
+  }
+  return { actionToAckMs: result['ack-query'], releaseAckToAckMs: result['ack-query'],
+    releaseAckToAbsenceMs: result['process-check'] };
+}
+function validatedPairs(pairs) {
+  assert.equal(pairs.length, 5, 'Require five fresh pairs');
+  const validated = pairs.map(pair => {
+    assert.equal(pair.length, 2);
+    return pair.map(evidence => ({ evidence, values: assertFunctional(evidence), brackets: observerBrackets(evidence) }));
+  });
+  const chronological = validated.flat().sort((a,b) => a.evidence.startedAtMs - b.evidence.startedAtMs);
+  assert.equal(new Set(chronological.map(arm => arm.evidence.runId)).size, 10, 'Ten fresh owned runs are required');
+  assert.equal(new Set(chronological.map(arm => arm.evidence.companyId)).size, 10, 'Ten fresh disposable invocations are required');
+  for (const [index,arm] of chronological.entries()) {
+    assert(Number.isSafeInteger(arm.evidence.startedAtMs) && Number.isSafeInteger(arm.evidence.finishedAtMs));
+    assert(arm.evidence.finishedAtMs >= arm.evidence.startedAtMs);
+    if (index) assert(chronological[index-1].evidence.finishedAtMs < arm.evidence.startedAtMs,
+      'Arms must not overlap');
+  }
+  validated.forEach((pair,index) => {
+    assert.equal(pair[0].evidence.startedAtMs, chronological[2*index + index%2].evidence.startedAtMs,
+      'Pairs must alternate baseline-first then candidate-first in chronological order');
+    assert.equal(pair[1].evidence.startedAtMs, chronological[2*index + (index%2 ? 0 : 1)].evidence.startedAtMs);
+  });
+  return validated;
+}
+export function noiseEnvelope(pairs) {
+  const validated = validatedPairs(pairs), chronological = validated.flat().sort((a,b) => a.evidence.startedAtMs - b.evidence.startedAtMs);
+  for (const [index,arm] of chronological.entries()) {
+    assert(Number.isSafeInteger(arm.evidence.startedAtMs) && Number.isSafeInteger(arm.evidence.finishedAtMs));
+    assert(arm.evidence.finishedAtMs >= arm.evidence.startedAtMs);
+    if (index) assert(chronological[index-1].evidence.finishedAtMs < arm.evidence.startedAtMs,
+      'A/A requires ten distinct non-overlapping chronological arms');
+  }
+  const variants = new Set(chronological.map(arm => String(arm.evidence.variant).toLowerCase()));
+  assert.equal(variants.size, 1, 'A/A calibration must use one baseline variant');
+  const baselineVariant = [...variants][0]; assert(['b0','b1'].includes(baselineVariant));
+  const result = { schema: 'paperclip.native-ingestion.blocked-stop-noise.v1', protocol: PROTOCOL, baselineVariant,
+    workloadSha256: WORKLOAD_SHA256, precisionRule: PRECISION_RULE, precisionRuleSha256: PRECISION_RULE_SHA256,
+    sampleCounts: { pairs: 5, arms: 10 }, suitable: false, noiseFrozen: false, metrics: {},
+    arms: chronological.map(arm => ({ reportSha256: hashReport(arm.evidence), startedAtMs: arm.evidence.startedAtMs,
+      finishedAtMs: arm.evidence.finishedAtMs, values: arm.values, observerBrackets: arm.brackets })),
+    rawArms: chronological.map(arm => arm.evidence), pairBindings: validated.map(pair => pair.map(arm => hashReport(arm.evidence))),
+    sourceDigestScope: 'SHA256 of JSON.stringify(parsed raw arm); owning raw-byte seals are separately required' };
+  for (const metric of METRICS) {
+    const values = chronological.map(arm => arm.values[metric]), pooledMedianMs = median(values);
+    const baselineValues = validated.map(pair => pair[0].values[metric]), candidateValues = validated.map(pair => pair[1].values[metric]);
+    const baselineMedianMs = median(baselineValues), candidateMedianMs = median(candidateValues);
+    const differencesMs = validated.map(pair => pair[1].values[metric] - pair[0].values[metric]);
+    const maximumAbsolutePairedDifferenceMs = Math.max(...differencesMs.map(Math.abs));
+    const firstFiveMedianMs = median(values.slice(0,5)), lastFiveMedianMs = median(values.slice(5));
+    const absoluteChronologicalMedianDriftMs = Math.abs(lastFiveMedianMs - firstFiveMedianMs);
+    const precisionBudgetMs = Math.max(PRECISION_RULE.floorMs, PRECISION_RULE.pooledMedianFraction * pooledMedianMs);
+    const observerBracketWidthsMs = chronological.map(arm => arm.brackets[metric].widthMs);
+    const floorDominated = PRECISION_RULE.pooledMedianFraction * pooledMedianMs <= PRECISION_RULE.floorMs;
+    result.metrics[metric] = { sampleCount: 10, pairCount: 5, pooledMedianMs, baselineMedianMs, candidateMedianMs,
+      absoluteMedianDifferenceMs: Math.abs(candidateMedianMs - baselineMedianMs),
+      medianDifferencePercent: floorDominated ? null : 100 * (candidateMedianMs - baselineMedianMs) / baselineMedianMs,
+      ...spread(values), pairedDifferencesMs: differencesMs, maximumAbsolutePairedDifferenceMs,
+      firstFiveMedianMs, lastFiveMedianMs, absoluteChronologicalMedianDriftMs, precisionBudgetMs,
+      observerBracketWidthsMs, maximumObserverBracketMs: Math.max(...observerBracketWidthsMs),
+      suitable: maximumAbsolutePairedDifferenceMs <= precisionBudgetMs && absoluteChronologicalMedianDriftMs <= precisionBudgetMs
+        && observerBracketWidthsMs.every(width => width <= precisionBudgetMs),
+      noiseMs: null, floorDominated, resolutionLabel: floorDominated ? '100 ms resolution floor' : 'Observer brackets and budget reported',
+      subfloorOrP99ClaimsAllowed: false, percentageSpeedClaimsAllowed: !floorDominated };
+  }
+  result.suitable = METRICS.every(metric => result.metrics[metric].suitable);
+  result.noiseFrozen = result.suitable;
+  if (result.suitable) for (const metric of METRICS) result.metrics[metric].noiseMs = result.metrics[metric].maximumAbsolutePairedDifferenceMs;
+  return result;
+}
+export function assertNoiseEnvelope(noise) {
+  assert.equal(noise?.schema, 'paperclip.native-ingestion.blocked-stop-noise.v1');
+  assert.equal(noise.protocol, PROTOCOL); assert.equal(noise.workloadSha256, WORKLOAD_SHA256);
+  assert.equal(noise.precisionRuleSha256, PRECISION_RULE_SHA256); assert.deepEqual(noise.precisionRule, PRECISION_RULE);
+  assert.deepEqual(noise.sampleCounts, { pairs: 5, arms: 10 });
+  assert.equal(noise.suitable, true, 'Unsuitable A/A cannot freeze a noise envelope'); assert.equal(noise.noiseFrozen, true);
+  assert.equal(noise.rawArms?.length, 10);
+  // Recompute suitability and all numeric limits from retained raw arms. A
+  // caller cannot inflate a budget or flip a failed suitability flag.
+  const byDigest = new Map(noise.rawArms.map(arm => [hashReport(arm), arm]));
+  assert.equal(noise.pairBindings?.length, 5);
+  const logical = noise.pairBindings.map(pair => {
+    assert.equal(pair.length, 2);
+    return pair.map(digest => { const raw = byDigest.get(digest); assert(raw, 'Frozen arm digest mismatch'); return raw; });
+  });
+  const recomputed = noiseEnvelope(logical);
+  assert.equal(recomputed.suitable, true);
+  assert.deepEqual(noise.metrics, recomputed.metrics, 'Frozen noise or precision limit changed');
+  assert.equal(noise.baselineVariant, recomputed.baselineVariant);
+  assert.deepEqual(noise.arms, recomputed.arms, 'Frozen chronological arms changed');
+  return noise;
+}
+export function comparePairs(pairs, noise) {
+  const validated = validatedPairs(pairs); assertNoiseEnvelope(noise);
+  for (const [baseline] of validated) assert.equal(String(baseline.evidence.variant).toLowerCase(), noise.baselineVariant,
+    'Comparisons must use their own baseline calibration');
+  return Object.fromEntries(METRICS.map(metric => {
+    const calibrated = noise.metrics[metric], deltas = validated.map(([baseline,candidate]) => candidate.values[metric] - baseline.values[metric]);
+    const baselineValues = validated.map(pair => pair[0].values[metric]), candidateValues = validated.map(pair => pair[1].values[metric]);
+    const baselineMedianMs = median(baselineValues), candidateMedianMs = median(candidateValues);
+    const observerBracketWidthsMs = validated.map(pair => pair.map(arm => arm.brackets[metric].widthMs));
+    const floorDominated = calibrated.floorDominated || PRECISION_RULE.pooledMedianFraction * Math.min(baselineMedianMs,candidateMedianMs) <= PRECISION_RULE.floorMs;
+    return [metric, { sampleCounts: { pairs: 5, arms: 10 }, baselineMedianMs, candidateMedianMs, deltaMedianMs: median(deltas),
+      medianDifferencePercent: floorDominated ? null : 100 * (candidateMedianMs - baselineMedianMs) / baselineMedianMs,
+      deltasMs: deltas, noiseMs: calibrated.noiseMs, precisionBudgetMs: calibrated.precisionBudgetMs,
+      baselineSpread: spread(baselineValues), candidateSpread: spread(candidateValues), ...spread(deltas),
+      observerBracketWidthsMs, floorDominated, resolutionLabel: floorDominated ? '100 ms resolution floor' : 'Observer brackets and budget reported',
+      subfloorOrP99ClaimsAllowed: false, percentageSpeedClaimsAllowed: !floorDominated,
+      pass: deltas.every(delta => delta <= calibrated.noiseMs) && median(deltas) <= calibrated.noiseMs
+        && observerBracketWidthsMs.flat().every(width => width <= calibrated.precisionBudgetMs) }];
+  }));
+}
+function assertOptionalShared(row, companyId, runId) {
+  assert.equal(row.company_id, companyId); assert.equal(row.run_id, runId);
+  const timestamp = value => typeof value === 'string' && /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d+)?Z$/.test(value) && Number.isFinite(Date.parse(value));
+  const execution = row.shared_execution_cancellation;
+  if (execution != null) {
+    assert(execution && typeof execution === 'object' && !Array.isArray(execution));
+    assert(['requested','acknowledged'].includes(execution.state));
+    if (execution.state === 'requested') assert(timestamp(execution.requestedAt));
+    if (execution.state === 'acknowledged') assert(timestamp(execution.acknowledgedAt));
+    if (execution.requestedAt != null) assert(timestamp(execution.requestedAt));
+    if (execution.acknowledgedAt != null) assert(timestamp(execution.acknowledgedAt));
+    if (execution.requestedAt != null && execution.acknowledgedAt != null)
+      assert(Date.parse(execution.requestedAt) <= Date.parse(execution.acknowledgedAt));
+  }
+  const cancellation = row.run_cancellation;
+  if (cancellation != null) {
+    assert.equal(cancellation.source, 'operator'); assert.equal(cancellation.expected, true);
+    assert.equal(cancellation.initiator?.type, 'user');
+    assert(typeof cancellation.reason === 'string' && cancellation.reason.length > 0);
+    assert(timestamp(cancellation.recordedAt));
+  }
+}
+export function assertFunctional(e) {
+  metrics(e); observerBrackets(e);
+  assert.equal(e.prelude?.individualDeltas, WORKLOAD.prelude); assert.equal(e.prelude?.uniqueIdentities, WORKLOAD.prelude);
+  assert(e.prelude.verifiedBeforeEpochAtMs < e.epochMs);
+  assert(e.visibleBeforeLock?.length >= WORKLOAD.visibleBeforeLock);
+  assert.equal(e.lock?.id, e.runId); assert.equal(e.lock.company_id, e.companyId);
+  assert(e.appendBlockedBeforeStop?.observedAtMs < e.timing.requestAtMs);
+  assert(e.appendBlockedBeforeStop.rows.some(row => isAppendLockQuery(row.query) && row.blocking_pids.includes(e.lock.holder_pid)));
+  assert(e.heldSamples?.length >= 2);
+  for (const sample of e.heldSamples) {
+    assertHeldSample(sample, e.lock.holder_pid); assertOptionalShared(sample, e.companyId, e.runId);
+    assert(sample.queryStartedAtMs >= e.timing.requestAtMs && sample.observedAtMs <= e.timing.releaseRequestedAtMs);
+  }
+  assert(e.heldSamples.at(-1).emittedCount > e.heldSamples[0].emittedCount, 'Provider must still emit through the stall');
+  assertIntentAudit(e.ack); assertOptionalShared(e.ack, e.companyId, e.runId);
+  assert.equal(e.ack.intent.dispatchState, 'acknowledged');
+  if (e.sharedSettlement != null) {
+    assert.equal(e.sharedSettlement.runId, e.runId); assert.equal(e.sharedSettlement.companyId, e.companyId);
+    assert.equal(e.sharedSettlement.status, 'cancelled');
+    assertOptionalShared({ company_id: e.sharedSettlement.companyId, run_id: e.sharedSettlement.runId,
+      shared_execution_cancellation: e.sharedSettlement.executionCancellation, run_cancellation: e.sharedSettlement.cancellation }, e.companyId, e.runId);
+    if (e.sharedSettlement.nativeCancellation != null) assert.equal(e.sharedSettlement.nativeCancellation.intentId, e.ack.intent.intentId);
+  }
+  assert.equal(e.ack.company_id, e.companyId); assert.equal(e.ack.run_id, e.runId); assert.equal(e.ack.issue_id, e.issueId);
+  assert.equal(e.stopHttpStatus, 200);
+  assert.deepEqual([e.processesAfter?.runnerAbsent, e.processesAfter?.groupAbsent, e.processesAfter?.providerAbsent], [true,true,true]);
+  assert(e.timing.httpSettledAtMs >= e.timing.releaseRequestedAtMs);
+  const before = e.authorityBefore?.rows?.[0], after = e.authorityAfter?.rows?.[0];
+  for (const row of [before, after]) { assert.equal(row?.company_id, e.companyId); assert.equal(row?.run_id, e.runId); assert.equal(row.runtime_mode, 'native'); }
+  assert.equal(after.status, 'cancelled'); assert.equal(after.cancellation_dispatch_state, 'acknowledged');
+  assert(BigInt(after.process_stopped_seq) > BigInt(before.process_identity_seq));
+  assert.equal(after.process_stopped_source_event_id, null);
+  assert.equal(after.process_stopped.processPid, e.processesBefore.runner.pid);
+  assert.equal(after.process_stopped.processGroupId, e.processesBefore.group);
+  for (const process of [e.processesBefore.runner, e.processesBefore.provider]) {
+    assert(Number.isSafeInteger(process.pid) && process.pid > 1 && process.birth);
+    assert.equal(process.group, e.processesBefore.group);
+  }
+  assert.equal(e.lease?.heartbeatRunId, e.runId); assert.equal(e.lease.companyId, e.companyId);
+  assert.equal(e.lease.provider, 'local'); assert.equal(e.lease.providerLeaseId, null);
+  assert(e.lease.releasedAt && ['released','expired','failed'].includes(e.lease.status)); assert.notEqual(e.lease.cleanupStatus, 'failed');
+  const transcript = e.transcript;
+  assert.equal(transcript?.persistedAfterReload, true); assert.equal(transcript?.ordered, true);
+  assert.equal(transcript.resultAcceptedEvents, 0); assert.equal(transcript.preludeCount, WORKLOAD.prelude);
+  assert.equal(transcript.individualDeltas, transcript.deltas.length);
+  assert.equal(transcript.uniqueSourceIdentities, transcript.deltas.length);
+  const identities = new Set();
+  for (const [index,event] of transcript.deltas.entries()) {
+    assert.equal(event.runId, e.runId); assert.equal(event.eventType, 'item.delta');
+    assert(event.sourceInstanceId && event.sourceEventId && Number.isSafeInteger(event.sourceSeq) && event.sourceSeq > 0);
+    identities.add(`${event.sourceInstanceId}:${event.sourceEventId}:${event.sourceSeq}`);
+    assert.equal(event.payload.text, `[${e.clock.markerCode}${index.toString(36)}] `);
+    assert(e.clock.records.some(record => record.index === index && record.nonce === e.clock.nonce));
+  }
+  assert.equal(identities.size, transcript.deltas.length);
+  for (const marker of transcript.seen) assert(marker.index >= 0 && marker.index < transcript.deltas.length);
+  assert(e.clock.ended || e.clock.aborted); assert(!e.clock.error);
+  assert.equal(e.measurement?.actionToAckIncludesForcedWait, true);
+  assert.equal(e.measurement?.recording?.trace, 'off'); assert.equal(e.measurement?.recording?.video, 'off');
+  return metrics(e);
+}
diff --git a/tests/e2e/fixtures/native-ingestion-blocked-stop-protocol.test.mjs b/tests/e2e/fixtures/native-ingestion-blocked-stop-protocol.test.mjs
new file mode 100644
index 00000000000..26e7c5c0991
--- /dev/null
+++ b/tests/e2e/fixtures/native-ingestion-blocked-stop-protocol.test.mjs
@@ -0,0 +1,206 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { PROTOCOL, WORKLOAD as W, WORKLOAD_SHA256, METRICS, isAppendLockQuery, assertHeldSample,
+  assertIntentAudit, metrics, registration, noiseEnvelope, comparePairs, assertFunctional, observerBrackets, assertNoiseEnvelope, PRECISION_RULE } from './native-ingestion-blocked-stop-protocol.mjs';
+const evidence = (shift = 0) => ({ protocol: PROTOCOL, workloadSha256: WORKLOAD_SHA256, complete: true, cleanup: { complete: true },
+  timing: { actionAtMs: 1000, requestAtMs: 1005, releaseRequestedAtMs: 2005, releaseCommitAckAtMs: 2007,
+    absenceObservedAtMs: 2030 + shift, ackObservedAtMs: 2040 + shift } });
+const sample = () => ({ httpPending: true, intent: null, auditIds: [], processesAlive: true, clockOpen: true, blockers: [{ blocking_pids: [88] }] });
+const intentRow = () => ({ company_id: 'c', run_id: 'r', issue_id: 'i', intent: {
+  schema: 'paperclip.native-cancellation.v1', companyId: 'c', runId: 'r', issueId: 'i',
+  intentId: 'own', intentAuditId: 'a', dispatchState: 'acknowledged', acknowledgementAuditId: 'b',
+  scope: 'run', reasonCode: 'cancellation_run_only', dispatched: true, decisionId: null },
+  audits: [{ id: 'a', action: 'native.cancellation_intent_recorded', details: { intentId: 'own' } },
+    { id: 'b', action: 'native.cancellation_dispatch_acknowledged', details: { intentId: 'own', intentAuditId: 'a', dispatched: true, decisionId: null } }] });
+
+test('geometry fits the unchanged 4,000 character bound, includes existing emitted history', () => {
+  const chars = '.'.repeat(W.prelude - 1) + ` PRELUDE_${'a'.repeat(32)}_READY `
+    + Array.from({ length: W.events }, (_, index) => `[00${index.toString(36)}] `).join('');
+  assert(chars.length < 4000); assert.equal(W.prelude, 1000); assert.equal(W.events, 256); assert.equal(W.intervalMs, 100);
+});
+test('B0 and candidate append SQL match while cancellation full-row and unrelated SQL do not', () => {
+  for (const extra of ['', ', "next_event_seq", "event_cursor_projection_seq"']) assert(isAppendLockQuery(
+    `select "company_id", "agent_id"${extra} from "heartbeat_runs" where "heartbeat_runs"."id" = $1 limit $2 for update`));
+  assert(!isAppendLockQuery('select "id", "company_id", "agent_id" from "heartbeat_runs" where "heartbeat_runs"."id" = $1 for update'));
+  assert(!isAppendLockQuery('select "company_id", "agent_id" from "heartbeat_runs" where "heartbeat_runs"."id" = $1'));
+});
+test('held sample requires every barrier and physical liveness proof', () => {
+  assertHeldSample(sample(), 88);
+  for (const patch of [{ httpPending: false }, { intent: {} }, { auditIds: ['a'] }, { processesAlive: false }, { clockOpen: false }, { blockers: [] }])
+    assert.throws(() => assertHeldSample({ ...sample(), ...patch }, 88));
+  assert.throws(() => assertHeldSample(sample(), 89));
+});
+test('ACK correlates both committed audits to the same owned intent', () => {
+  assertIntentAudit(intentRow());
+  for (const mutate of [row => { row.intent.runId = 'foreign'; }, row => { row.audits.pop(); },
+    row => { row.audits[1].details.intentId = 'foreign'; }, row => { row.intent.intentAuditId = 'missing'; }]) {
+    const row = intentRow(); mutate(row); assert.throws(() => assertIntentAudit(row));
+  }
+});
+test('full action latency retains forced wait; release metrics use COMMIT ACK and also retain request-origin bounds', () => {
+  assert.deepEqual(metrics(evidence()), { actionToAckMs: 1040, releaseAckToAbsenceMs: 23, releaseAckToAckMs: 33,
+    releaseRequestToAbsenceMs: 25, releaseRequestToAckMs: 35 });
+  for (const key of ['actionAtMs','requestAtMs','releaseRequestedAtMs','releaseCommitAckAtMs','absenceObservedAtMs','ackObservedAtMs']) {
+    const e = evidence(); delete e.timing[key]; assert.throws(() => metrics(e));
+  }
+  const e = evidence(); e.timing.releaseRequestedAtMs--; assert.throws(() => metrics(e));
+  e.timing.releaseRequestedAtMs++; e.complete = false; assert.throws(() => metrics(e));
+});
+test('registered companion is 50 separate alternating arms with fresh B0 and B1 A/A', () => {
+  const arms = registration(); assert.equal(arms.length, 50);
+  for (const stage of ['b0-aa','b1-aa','b0-b1','b1-b2','b0-b2']) {
+    const rows = arms.filter(a => a.stage === stage); assert.equal(rows.length, 10);
+    for (let pair = 1; pair <= 5; pair++) assert.equal(rows.filter(a => a.pair === pair).length, 2);
+    assert.deepEqual(rows.slice(0, 4).map(a => a.role), ['baseline','candidate','candidate','baseline']);
+  }
+});
+
+const functional = () => {
+  const e = evidence(), identity = { company_id: 'c', run_id: 'r', runtime_mode: 'native' };
+  return { ...e, variant: 'b0', startedAtMs: 100, finishedAtMs: 3000, companyId: 'c', runId: 'r', issueId: 'i', epochMs: 900,
+    prelude: { individualDeltas: 1000, uniqueIdentities: 1000, verifiedBeforeEpochAtMs: 850 },
+    visibleBeforeLock: [0,1,2], lock: { id: 'r', company_id: 'c', holder_pid: 88 },
+    appendBlockedBeforeStop: { observedAtMs: 1004, rows: [{ query: 'select "company_id", "agent_id" from "heartbeat_runs" where "heartbeat_runs"."id" = $1 for update', blocking_pids: [88] }] },
+    heldSamples: [{ ...sample(), company_id: 'c', run_id: 'r', queryStartedAtMs: 1010, observedAtMs: 1015, emittedCount: 3 },
+      { ...sample(), company_id: 'c', run_id: 'r', queryStartedAtMs: 1995, observedAtMs: 2004, emittedCount: 13 }], ack: intentRow(), stopHttpStatus: 200,
+    timing: { ...e.timing, httpSettledAtMs: 2042, lastAckNotObservedAtMs: 2036, lastProcessesPresentAtMs: 2026 },
+    observerSamples: [{ kind: 'ack-query', startedAtMs: 2035, completedAtMs: 2036, durationMs: 1, value: false },
+      { kind: 'ack-query', startedAtMs: 2039, completedAtMs: 2040, durationMs: 1, value: true },
+      { kind: 'process-check', startedAtMs: 2025, completedAtMs: 2026, durationMs: 1, value: false },
+      { kind: 'process-check', startedAtMs: 2029, completedAtMs: 2030, durationMs: 1, value: true }], processesBefore: { runner: { pid: 10, group: 10, birth: 'birth' },
+      provider: { pid: 11, group: 10, birth: 'birth' }, group: 10 }, processesAfter: { runnerAbsent: true, groupAbsent: true, providerAbsent: true },
+    authorityBefore: { rows: [{ ...identity, process_identity_seq: '1' }] },
+    authorityAfter: { rows: [{ ...identity, status: 'cancelled', cancellation_dispatch_state: 'acknowledged', process_stopped_seq: '20',
+      process_stopped_source_event_id: null, process_stopped: { processPid: 10, processGroupId: 10 } }] },
+    lease: { heartbeatRunId: 'r', companyId: 'c', provider: 'local', providerLeaseId: null, releasedAt: 'time', status: 'released', cleanupStatus: 'success' },
+    transcript: { individualDeltas: 3, uniqueSourceIdentities: 3, persistedAfterReload: true, ordered: true, resultAcceptedEvents: 0,
+      preludeCount: 1000, seen: [{ index: 0 },{ index: 1 },{ index: 2 }], deltas: [0,1,2].map(index => ({ runId: 'r', eventType: 'item.delta',
+        sourceInstanceId: 'source', sourceEventId: `id${index}`, sourceSeq: index+1, payload: { text: `[00${index}] ` } })) },
+    clock: { markerCode: '00', nonce: 'nonce', ended: true, records: [0,1,2].map(index => ({ index, nonce: 'nonce' })) },
+    measurement: { actionToAckIncludesForcedWait: true, recording: { trace: 'off', video: 'off' } } };
+};
+test('functional oracle accepts complete correlated proof and rejects plausible missing or wrong outcomes', () => {
+  assertFunctional(functional());
+  const mutations = [e => { delete e.ack; }, e => { e.ack.intent.intentId = 'other'; },
+    e => { e.appendBlockedBeforeStop.rows[0].blocking_pids = []; }, e => { e.prelude.individualDeltas = 999; },
+    e => { e.authorityAfter.rows[0].process_stopped.processPid = 99; }, e => { e.processesAfter.providerAbsent = false; },
+    e => { e.heldSamples[1].emittedCount = 3; }, e => { e.transcript.deltas[1].payload.text = '[000] '; },
+    e => { e.transcript.deltas[1].sourceEventId = 'id0'; e.transcript.deltas[1].sourceSeq = 1; },
+    e => { e.transcript.persistedAfterReload = false; }, e => { e.measurement.recording.trace = 'on'; }];
+  for (const mutate of mutations) { const e = functional(); mutate(e); assert.throws(() => assertFunctional(e)); }
+});
+
+test('shared decision is correlated when present and absent run-only decisions stay valid', () => {
+  const row = intentRow(); assertIntentAudit(row);
+  row.intent.decisionId = 'decision'; row.audits[1].details.decisionId = 'decision';
+  row.shared_decision = { id: 'decision', companyId: 'c', runId: 'r', issueId: 'i' }; assertIntentAudit(row);
+  row.shared_decision.runId = 'foreign'; assert.throws(() => assertIntentAudit(row));
+});
+
+const arm = (index, shift = 0, variant = 'b0') => {
+  const offset = index * 10000;
+  const evidence = JSON.parse(JSON.stringify(functional()), (key,value) => {
+    if (value === 'r') return `r${index}`; if (value === 'c') return `c${index}`; if (value === 'i') return `i${index}`;
+    return typeof value === 'number' && (key.endsWith('AtMs') || key === 'epochMs') ? value + offset : value;
+  });
+  evidence.variant = variant;
+  for (const key of ['ackObservedAtMs','absenceObservedAtMs','lastAckNotObservedAtMs','lastProcessesPresentAtMs','httpSettledAtMs'])
+    evidence.timing[key] += shift;
+  for (const sample of evidence.observerSamples) { sample.startedAtMs += shift; sample.completedAtMs += shift; }
+  return evidence;
+};
+const pairs = (shift = () => 0) => Array.from({ length: 5 }, (_, pair) => [
+  arm(2*pair + (pair % 2), shift(pair,0)), arm(2*pair + (pair % 2 ? 0 : 1), shift(pair,1))]);
+
+test('noise artifact freezes actual suitable A/A limits with counts, spread, chronological drift and resolution labels', () => {
+  const noise = noiseEnvelope(pairs((pair,side) => side ? pair+1 : 0));
+  assert.equal(noise.suitable, true); assert.equal(noise.noiseFrozen, true); assertNoiseEnvelope(noise);
+  assert.deepEqual(noise.sampleCounts, { pairs: 5, arms: 10 }); assert.equal(noise.rawArms.length, 10);
+  for (const metric of METRICS) {
+    const row = noise.metrics[metric]; assert.equal(row.noiseMs, 5); assert.equal(row.sampleCount, 10);
+    assert.equal(row.precisionBudgetMs, Math.max(2*W.pollIntervalMs, 0.10*row.pooledMedianMs));
+    assert(row.maximumObserverBracketMs <= row.precisionBudgetMs);
+  }
+  assert.equal(noise.metrics.releaseAckToAckMs.resolutionLabel, '100 ms resolution floor');
+  assert.equal(noise.metrics.releaseAckToAckMs.medianDifferencePercent, null);
+  assert.equal(noise.metrics.releaseAckToAckMs.percentageSpeedClaimsAllowed, false);
+});
+test('every calibration and comparison arm must pass the complete functional oracle', () => {
+  const noise = noiseEnvelope(pairs());
+  const mutations = [e => { delete e.lock; }, e => { delete e.ack; }, e => { delete e.processesAfter; },
+    e => { delete e.lease; }, e => { delete e.transcript; }, e => Object.assign(e, evidence()),
+    e => { e.transcript.persistedAfterReload = false; }];
+  for (const mutate of mutations) {
+    const invalid = pairs(); mutate(invalid[4][1]);
+    assert.throws(() => noiseEnvelope(invalid)); assert.throws(() => comparePairs(invalid, noise));
+  }
+  const forged = pairs(); forged[0][0] = evidence();
+  assert.throws(() => noiseEnvelope(forged)); assert.throws(() => comparePairs(forged, noise));
+});
+test('paired jitter and chronological drift outside prospective budget retain all arms and cannot freeze noise', () => {
+  for (const data of [pairs((pair,side) => side ? 150 : 0), pairs(pair => pair * 60)]) {
+    const noise = noiseEnvelope(data);
+    assert.equal(noise.suitable, false); assert.equal(noise.noiseFrozen, false); assert.equal(noise.rawArms.length, 10);
+    assert(METRICS.every(metric => noise.metrics[metric].noiseMs === null));
+    assert.throws(() => assertNoiseEnvelope(noise)); assert.throws(() => comparePairs(pairs(), noise));
+  }
+  const drift = noiseEnvelope(pairs(pair => pair * 60));
+  assert.equal(drift.metrics.releaseAckToAckMs.maximumAbsolutePairedDifferenceMs, 0);
+  assert(drift.metrics.releaseAckToAckMs.absoluteChronologicalMedianDriftMs > drift.metrics.releaseAckToAckMs.precisionBudgetMs);
+});
+test('raw observer brackets retain actual query/check durations and reject missing or forged timing', () => {
+  const e = functional(), brackets = observerBrackets(e);
+  assert.equal(brackets.releaseAckToAckMs.widthMs, 5);
+  assert.equal(brackets.releaseAckToAckMs.negativeDurationMs, 1);
+  assert.equal(brackets.releaseAckToAbsenceMs.successfulDurationMs, 1);
+  e.observerSamples[0].durationMs = 0; assert.throws(() => observerBrackets(e));
+  delete e.observerSamples; assert.throws(() => assertFunctional(e));
+});
+test('a wide observer bracket invalidates A/A suitability and comparison despite stable latency medians', () => {
+  const data = pairs(() => 120), e = data[0][0];
+  e.observerSamples = e.observerSamples.filter(sample => sample.kind !== 'ack-query' || sample.value);
+  delete e.timing.lastAckNotObservedAtMs;
+  const unsuitable = noiseEnvelope(data);
+  assert.equal(unsuitable.metrics.releaseAckToAckMs.maximumAbsolutePairedDifferenceMs, 0);
+  assert.equal(unsuitable.suitable, false); assert.throws(() => assertNoiseEnvelope(unsuitable));
+  const noise = noiseEnvelope(pairs(() => 120));
+  const result = comparePairs(data, noise);
+  assert.equal(result.releaseAckToAckMs.pass, false);
+  assert.equal(result.releaseAckToAckMs.noiseMs, 0);
+});
+test('comparison uses unchanged frozen noise and budget; one paired regression or inflated artifact fails', () => {
+  const calibration = pairs((pair,side) => side ? pair+1 : 0), noise = noiseEnvelope(calibration);
+  assert(Object.values(comparePairs(calibration, noise)).every(row => row.pass));
+  const regression = pairs((pair,side) => side ? 6 : 0);
+  assert(Object.values(comparePairs(regression, noise)).every(row => !row.pass));
+  const forged = structuredClone(noise); forged.metrics.releaseAckToAckMs.noiseMs = 999;
+  assert.throws(() => comparePairs(pairs(), forged));
+  const inflated = structuredClone(noise); inflated.metrics.releaseAckToAckMs.precisionBudgetMs = 999;
+  assert.throws(() => comparePairs(pairs(), inflated));
+  assert.throws(() => noiseEnvelope(pairs().slice(1)));
+});
+test('optional shared cancellation accepts absent/requested B0 metadata and validates present state, time, attribution and run scope', () => {
+  const when = '2026-11-04T10:00:00.000Z';
+  const e = functional(); assertFunctional(e);
+  e.ack.shared_execution_cancellation = { state: 'requested', requestedAt: when };
+  e.ack.run_cancellation = { source: 'operator', expected: true, initiator: { type: 'user' }, reason: 'Operator Stop', recordedAt: when };
+  assertFunctional(e);
+  e.ack.shared_execution_cancellation = { state: 'acknowledged', acknowledgedAt: when }; assertFunctional(e);
+  for (const patch of [{ state: 'requested' }, { state: 'acknowledged', acknowledgedAt: 'invalid' },
+    { state: 'other', requestedAt: when }]) {
+    const bad = structuredClone(e); bad.ack.shared_execution_cancellation = patch; assert.throws(() => assertFunctional(bad));
+  }
+  const wrong = structuredClone(e); wrong.ack.run_cancellation.source = 'provider'; assert.throws(() => assertFunctional(wrong));
+  const foreign = structuredClone(e); foreign.sharedSettlement = { companyId: 'c', runId: 'foreign', status: 'cancelled' };
+  assert.throws(() => assertFunctional(foreign));
+});
+
+test('calibration and comparison reject reused runs, overlapping arms and nonalternating chronology', () => {
+  const noise = noiseEnvelope(pairs());
+  for (const corrupt of [data => { data[4][1] = data[0][0]; },
+    data => { data[0][1].startedAtMs = data[0][0].finishedAtMs; },
+    data => { data[1].reverse(); }]) {
+    const invalid = pairs(); corrupt(invalid);
+    assert.throws(() => noiseEnvelope(invalid)); assert.throws(() => comparePairs(invalid, noise));
+  }
+});
diff --git a/tests/e2e/fixtures/native-ingestion-blocked-stop-validate.mjs b/tests/e2e/fixtures/native-ingestion-blocked-stop-validate.mjs
new file mode 100644
index 00000000000..e6eb8383dd6
--- /dev/null
+++ b/tests/e2e/fixtures/native-ingestion-blocked-stop-validate.mjs
@@ -0,0 +1,22 @@
+// Read-only validation of an independently extracted raw attachment; no app/DB/process execution.
+import { readFile, writeFile } from 'node:fs/promises';
+import { createHash } from 'node:crypto';
+import { pathToFileURL } from 'node:url';
+import { assertFunctional, PROTOCOL, WORKLOAD_SHA256, registration } from './native-ingestion-blocked-stop-protocol.mjs';
+export async function validateFile(file) {
+  const bytes = await readFile(file), evidence = JSON.parse(bytes.toString('utf8'));
+  const metrics = assertFunctional(evidence);
+  return { protocol: PROTOCOL, workloadSha256: WORKLOAD_SHA256, sourceFile: file,
+    sourceSha256: createHash('sha256').update(bytes).digest('hex'), sourceRevision: evidence.sourceRevision,
+    runId: evidence.runId, metrics, functionalPass: true,
+    qualification: 'Functional gate only; owning Playwright, frozen preflight, cleanup and paired noise/comparison campaign remain separately required' };
+}
+if (process.argv[1] && import.meta.url === pathToFileURL(process.argv[1]).href) {
+  if (process.argv[2] === '--registration') process.stdout.write(`${JSON.stringify(registration(), null, 2)}\n`);
+  else {
+    if (!process.argv[2]) throw new Error('Pass extracted raw companion evidence JSON, or --registration');
+    const result = await validateFile(process.argv[2]);
+    if (process.argv[3]) await writeFile(process.argv[3], `${JSON.stringify(result, null, 2)}\n`, { flag: 'wx' });
+    else process.stdout.write(`${JSON.stringify(result, null, 2)}\n`);
+  }
+}
diff --git a/tests/e2e/fixtures/native-ingestion-blocked-stop.md b/tests/e2e/fixtures/native-ingestion-blocked-stop.md
new file mode 100644
index 00000000000..d26fc8eb16e
--- /dev/null
+++ b/tests/e2e/fixtures/native-ingestion-blocked-stop.md
@@ -0,0 +1,184 @@
+# Existing-history blocked Stop companion (prospective v1)
+
+Status: local source and pure oracle calibration only. No application, browser,
+PostgreSQL, VM or quantitative arm has run. No runtime qualification or performance
+claim follows from the pure tests. Execution needs lead release after independent
+source review. This is separate from the immutable H5c 50-arm campaign.
+
+## Registration and ownership
+
+Explicit config: `tests/e2e/playwright-native-ingestion-blocked-stop.config.ts`.
+Explicit source: `tests/e2e/native-event-ingestion-blocked-stop.journey.ts`.
+Protocol: `blocked-stop-history-v1`; workload digest comes from the exact exported
+`WORKLOAD` JSON in `native-ingestion-blocked-stop-protocol.mjs`.
+
+The config inherits the unchanged H5c production-built app bootstrap, local
+Codex command fixture, normal local environment, and shipped UI. It selects only
+the companion source and fixes a 900-second test budget. There is one owned
+control agent and one task created and assigned through visible normal controls.
+Provider execution is a deterministic existing Codex leaf fixture, not a live
+model or a real Cloud provider. This companion grants no Cloud Stop qualification.
+No resolver override, HTTP/API change, persisted outcome seeding or app/product
+code change is included. Authority/gate/paint code is a bounded copy from H5c
+`e431ec63d41fe90c6fd68bd2fc2bb969feeca917`; the original nine measured files stay
+unchanged. The new files have their own source identity and review.
+
+## Fixed workload and functional gate
+
+All variants emit 1,000 actual prelude deltas, independently read back through
+normal event APIs before the common gate releases. They then emit 256 compact
+markers at 100 ms, fitting the unchanged 4,000 character Rust text bound together
+with the prelude. Readiness is bounded at 300 seconds, measured streaming at
+120 seconds, terminal settlement at 180 seconds; original later 30-second ACK
+and lease observations remain after settlement. Setup stays inside the owning
+900-second test budget. Server bootstrap retains its existing separate limit.
+
+After at least three visible markers and before Stop, a separately owned
+PostgreSQL connection acquires `FOR UPDATE` on the exact company/run row. A
+second connection reads `pg_stat_activity` and `pg_blocking_pids` and must see
+an actual append query waiting on that holder. Its SELECT projection prefix is
+checked against the B0/B1/B2 source signatures, distinguishing cancellation's
+full-row SELECT. Raw SQL metadata is retained privately; no product hook is used.
+
+The ordinary visible Stop button must cause the actual matching public POST.
+For at least 1,000 ms after that observed request, repeated independent snapshots
+must show pending HTTP, no committed native cancellation intent or audit, the
+same runner/provider PID births alive in their exact group, and an open fixture
+clock. The fixture closes that clock on `turn/interrupt`. Provider emissions must
+continue across the hold. The hold is not subtracted from action-to-ACK latency.
+A late sample/query/timer can overrun the minimum; actual boundaries stay visible.
+
+Release records both COMMIT request and COMMIT response acknowledgement. Neither
+is claimed to be the exact PostgreSQL commit instant. Independent observations
+then require the cancellation intent and its own matching committed audit,
+native acknowledged dispatch and its own matching acknowledgement audit,
+normal cancelled settlement, successful Stop HTTP, server-authored
+`native.local_process_stopped` receipt for the exact prior PID/group, independently
+absent runner/group/provider, and the exact owned local lease released without
+failed cleanup. Transcript checks require complete compact payloads, unique source
+identities, ordered canonical prefix, original emission clocks, zero accepted
+results, and persistence after reload. The raw transport recovery policy stays
+unchanged: raw fixture emissions after the canonical prefix are not represented
+as universally database-durable.
+
+The native receipt, shared `executionCancellation` metadata (including absence)
+and public cancelled run are recorded separately. The native dispatch audit must
+match the same intent and intent audit, `dispatched: true`, and nullable decision
+ID. A non-null decision is independently correlated through the owned
+`status_decisions` company/issue/run row. Run-only Stop may have no decision; a
+missing optional decision or shared field is not silently invented. A shared ACK field is not synthesized from
+row `recordedAt` or a provider clock. Source/runtime review must confirm which
+shared receipt contract the serving revision exposes before releasing the probe.
+No universal 30-second click-to-ACK gate is introduced.
+
+Every actual ACK query and process check through its first success retains its
+start, completion, duration and boolean observation. An uncertainty bracket runs
+from the last negative query/check start (conservative for snapshot-read timing)
+or release-COMMIT-ACK when no negative was seen, through first successful
+completion. Both negative and successful operation durations stay explicit.
+
+Timing includes action-to-observed-native-ACK, release-COMMIT-ACK-to-independently
+observed absence, and release-COMMIT-ACK-to-observed-native-ACK. Both release
+request-origin values also remain. Last unsuccessful and successful-query/check
+bounds are retained with a 50-ms poll interval; query duration and scheduling add
+uncertainty. Screenshots and reload happen after those timing observations.
+
+Any failure, timeout, censored observation, query/clock fault or cleanup error
+makes the arm ineligible. Partial raw Playwright results and the final attachment
+remain even after failure. Cleanup first releases/rolls back only the owned lock,
+closes both connections, retires its clock, settles only its owned run and restores
+owned experimental settings. The external operator must independently prove the
+server, database, runner, provider and browser are gone before the next arm.
+
+## Separate quantitative registration (50 short arms)
+
+Generate the explicit registration without executing an app:
+
+```sh
+node tests/e2e/fixtures/native-ingestion-blocked-stop-validate.mjs --registration
+```
+
+Order is B0 A/A five fresh alternating pairs, B1 A/A five fresh alternating pairs,
+then B0→B1, B1→B2 and B0→B2 five alternating pairs each. Each pair is two fresh
+owned invocations with matching data/load/payload/resource/cache conditions.
+There are no repeats hidden inside an invocation. Keep the original main 50 arms
+and their noise files untouched.
+
+Before any companion data, freeze this exact suitability rule independently per
+metric. The precision budget is `max(2 * 50 ms, 0.10 * pooled ten-arm A/A metric
+median)`. Both the maximum absolute paired difference and the absolute median
+drift between the first five and last five chronological arms must fit that
+budget. Every raw ACK/absence observer bracket must also fit the corresponding
+metric budget; action-to-ACK uses the ACK observer bracket. This is a
+measurement repeatability rule, not a product Stop deadline.
+
+Only suitable calibration freezes its observed maximum absolute paired
+difference as noise. B0 comparisons use B0 A/A; B1→B2 uses B1 A/A. Every paired
+candidate difference and their median must remain within that own frozen noise,
+and all comparison observer brackets must fit the frozen baseline precision
+budget. No unblocked Stop noise is reused. An unsuitable ten-arm calibration
+retains every raw arm and produces no usable noise envelope: no silent
+replacement, budget increase or inflated envelope follows from noisy data.
+
+`noiseEnvelope(pairs)` takes five logical `[baseline, candidate]` raw-report
+pairs whose chronological order alternates baseline-first then candidate-first.
+It validates the full functional oracle for every arm, requires ten distinct
+owned runs/companies with nonoverlapping arm times, and returns the structured
+`paperclip.native-ingestion.blocked-stop-noise.v1` artifact. This contains
+sample counts, all raw arms and report digests, logical pair bindings, actual
+absolute/percentage median differences, spread, chronological drift, budgets,
+query/check uncertainty brackets, suitability, and nullable noise values.
+Percentage fields are null when the 100-ms precision floor determines the
+budget. Those metrics are labeled **100 ms resolution floor** and cannot support
+subfloor, p99 or percentage speed claims. Ten observed arms do not establish p99.
+
+`assertNoiseEnvelope(artifact)` revalidates all retained functional proofs and
+recomputes suitability and numeric limits; unsuitable or inflated artifacts
+throw. `comparePairs(pairs, artifact)` validates every comparison arm's complete
+functional proof and returns per-metric `.pass` results using only that
+baseline's unchanged frozen noise and budget. It rejects reused runs,
+nonalternating/overlapping arms, missing lock/ACK/process/lease/transcript proof,
+and forged `complete` flags. Preserve all failures and censored arms outside
+these successful artifacts as well. A single functional probe is not
+quantitative nonregression evidence.
+
+## Reproduction and execution gates
+
+Credential-free local checks, with Node 24:
+
+```sh
+node --test tests/e2e/fixtures/native-ingestion-blocked-stop-protocol.test.mjs
+node --check tests/e2e/native-event-ingestion-blocked-stop.journey.ts
+node --check tests/e2e/playwright-native-ingestion-blocked-stop.config.ts
+node tests/e2e/fixtures/native-ingestion-blocked-stop-validate.mjs --registration
+```
+
+Before runtime, the lead must review/freeze the companion source, workload digest,
+registration, validator and companion-only release descriptor. Keep the reviewed
+H5c private runner `6b6376b01de6cdc15ca05343a0bdd5c00424f1d6c546b9b4d61cd76716b253c4`
+unchanged. A companion orchestrator should import its checked exported
+`validateVariantBuild`, `validateActualInventory`, `assertNoPreferredUiShadow`,
+`physicalQuietGuard`, `sealArmArtifacts` and `verifyRawArtifactSeals`; it must not
+invoke or alter the original stage plan. Bind each arm to exact source/build/UI,
+qualified receipt, full inventory manifest, Node/dependency/native pins, unchanged
+frozen fixture hashes, companion hashes, recording-off flags and a clean source.
+Use original B0 `bac53ec3`, B1 `07061a60`, unoptimized B2 `ca7cba17` only where
+explicitly released; a future optimized B2 needs its own qualified descriptor.
+The existing build receipt `a1259ba7…`, full inventory `d3766fc4…` and native binary
+`abb65bdc…` are provenance, not substitutes for current artifact validation.
+
+Only the performance owner may stage/execute on the sole benchmark VM, after
+lead release. First do discovery, narrow static typecheck, and one smallest
+functional qualification with raw Playwright, server/banner, PostgreSQL blocker,
+process/clock and external cleanup evidence. Validate its extracted attachment:
+
+```sh
+node tests/e2e/fixtures/native-ingestion-blocked-stop-validate.mjs RAW.json RECEIPT.json
+```
+
+Do not start the 50-arm registration until the source and runtime probe qualify.
+Capture quiet before/after-arm receipts, owning Playwright exit/status/duration,
+raw API/SQL/process evidence, immutable report seals, and all cleanup outcomes.
+The source validator is an additional functional oracle; it cannot establish the
+owning Playwright pass, infrastructure cleanup, build authenticity or performance
+on its own. Freeze separate B0/B1 A/A noise before nonregression comparisons.
diff --git a/tests/e2e/native-event-ingestion-blocked-stop.journey.ts b/tests/e2e/native-event-ingestion-blocked-stop.journey.ts
new file mode 100644
index 00000000000..7bcf955c90b
--- /dev/null
+++ b/tests/e2e/native-event-ingestion-blocked-stop.journey.ts
@@ -0,0 +1,312 @@
+import { randomUUID, createHash } from "node:crypto";
+import { execFileSync } from "node:child_process";
+import { readFile } from "node:fs/promises";
+import path from "node:path";
+import { expect, test, type Request } from "@playwright/test";
+import { json } from "./agent-chat.shared";
+import { runtimeAuthority, processAbsent } from "./fixtures/native-ingestion-blocked-stop-authority";
+import { openClock } from "./fixtures/native-ingestion-blocked-stop-clock";
+import { ownedDatabase, cancellationSnapshot, blockers } from "./fixtures/native-ingestion-blocked-stop-db";
+import { PROTOCOL, WORKLOAD as W, WORKLOAD_SHA256, assertHeldSample, assertIntentAudit, isAppendLockQuery, metrics, assertFunctional }
+  from "./fixtures/native-ingestion-blocked-stop-protocol.mjs";
+import { observeRunSettlement } from "./fixtures/native-ingestion-h5.mjs";
+
+const delay = (ms: number) => new Promise(resolve => setTimeout(resolve, ms));
+const birth = (pid: number) => {
+  const value = execFileSync("ps", ["-p", String(pid), "-o", "pid=,pgid=,lstart="], { encoding: "utf8" }).trim();
+  const match = value.match(/^(\d+)\s+(\d+)\s+(.+)$/);
+  if (!match || Number(match[1]) !== pid) throw new Error("Missing exact owned process birth identity");
+  return { pid, group: Number(match[2]), birth: match[3] };
+};
+
+test("existing-history Stop preserves its durable barrier behind a real blocked append", async ({ page, request }, info) => {
+  const appRoot = path.resolve(process.env.PAPERCLIP_INGESTION_APP_ROOT ?? "");
+  expect(process.env.PAPERCLIP_INGESTION_SERVER_ARTIFACT).toBe("compiled");
+  expect(process.env.PAPERCLIP_INGESTION_COMPANION_PROTOCOL).toBe(PROTOCOL);
+  const report: any = { protocol: PROTOCOL, workload: W, workloadSha256: WORKLOAD_SHA256, complete: false,
+    variant: process.env.PAPERCLIP_INGESTION_VARIANT, startedAtMs: Date.now(), timing: {}, heldSamples: [], observerSamples: [],
+    observedClock: "Independent observer wall clock; PostgreSQL row recordedAt is not a commit timestamp",
+    measurement: { pollIntervalMs: W.pollIntervalMs, releaseOrigin: "Owned COMMIT response acknowledgement",
+      releaseCommitBracket: "releaseRequestedAtMs..releaseCommitAckAtMs; exact server commit instant is unknown",
+      absenceAndAckUncertainty: "Last unsuccessful observation through successful query/process observation; polling plus query duration",
+      actionToAckIncludesForcedWait: true, noUniversalClickAckDeadline: true,
+      recording: { trace: info.project.use.trace, video: info.project.use.video }, quantitativeAcceptance: "Requires separately frozen companion A/A and five paired arms per comparison" } };
+  const clock = await openClock(page);
+  const company = await json(await request.post("/api/companies", { data: { name: `Blocked Stop ${Date.now()}` } }));
+  report.companyId = company.id;
+  const original = await json(await request.get("/api/instance/settings/experimental"));
+  let holder: any, observer: any, held = false, companyRunId: string | undefined;
+  let stopRequest: Request | undefined, stopSettled = false;
+  const nonce = randomUUID().replaceAll("-", ""), key = randomUUID().replaceAll("-", ""), code = clock.nextMarkerCode();
+  const stopFinished = (req: Request) => {
+    if (req === stopRequest) { stopSettled = true; report.timing.httpSettledAtMs = Date.now(); }
+  };
+  page.on("requestfinished", stopFinished);
+  page.on("requestfailed", stopFinished);
+  try {
+    const files = ["native-event-ingestion-blocked-stop.journey.ts", "playwright-native-ingestion-blocked-stop.config.ts",
+      "fixtures/native-ingestion-blocked-stop-authority.ts", "fixtures/native-ingestion-blocked-stop-clock.ts",
+      "fixtures/native-ingestion-blocked-stop-db.ts", "fixtures/native-ingestion-blocked-stop-protocol.mjs",
+      "native-event-ingestion.journey.ts", "playwright-native-ingestion.config.ts", "fixtures/in-feed-codex.mjs",
+      "fixtures/native-ingestion-bin/codex", "fixtures/composer-stop-codex-loader.mjs", "fixtures/native-ingestion-bootstrap.mjs",
+      "fixtures/native-ingestion-remote-server.mjs", "fixtures/native-ingestion-protocol-qualification.mjs", "fixtures/native-ingestion-h5.mjs"];
+    report.sourceHashes = Object.fromEntries(await Promise.all(files.map(async file => [file,
+      createHash("sha256").update(await readFile(path.join(import.meta.dirname, file))).digest("hex")])));
+    const harnessRoot = path.resolve(import.meta.dirname, "../..");
+    report.harnessProvenance = {
+      sourceRevision: execFileSync("git", ["rev-parse", "HEAD"], { cwd: harnessRoot, encoding: "utf8" }).trim(),
+      sourceStatus: execFileSync("git", ["status", "--porcelain", "--", "tests/e2e"], { cwd: harnessRoot, encoding: "utf8" }).trim(),
+      driverLockSha256: createHash("sha256").update(await readFile(path.join(harnessRoot, "pnpm-lock.yaml"))).digest("hex"),
+      inheritedH5cRevision: "e431ec63d41fe90c6fd68bd2fc2bb969feeca917",
+    };
+    report.sourceRevision = execFileSync("git", ["rev-parse", "HEAD"], { cwd: appRoot, encoding: "utf8" }).trim();
+    report.buildInfo = JSON.parse(await readFile(path.join(appRoot, "server/dist/build-info.json"), "utf8"));
+    expect(report.buildInfo.commit).toBe(report.sourceRevision);
+    report.serverEntrySha256 = createHash("sha256").update(await readFile(path.join(appRoot, "server/dist/index.js"))).digest("hex");
+    report.health = await json(await request.get("/api/health"));
+    await json(await request.patch("/api/instance/settings/experimental", { data: { enableNativeRunner: true, enableWorktreeRunExecution: true } }));
+    await json(await request.post(`/api/companies/${company.id}/user-secret-definitions`, { data: { key: "OPENAI_API_KEY", name: "Fixture credential" } }));
+    await json(await request.post(`/api/companies/${company.id}/me/user-secrets`, { data: { definitionKey: "OPENAI_API_KEY", value: "not-a-real-model-key" } }));
+    const environments = await json(await request.get(`/api/companies/${company.id}/environments?driver=local`));
+    expect(environments).toHaveLength(1);
+    const environment = environments[0]; expect(environment.driver).toBe("local");
+    const agent = await json(await request.post(`/api/companies/${company.id}/agents`, { timeout: 120_000, data: {
+      name: "Blocked Stop local control", role: "engineer", adapterType: "paperclip_runner", defaultEnvironmentId: environment.id,
+      adapterConfig: { provider: "codex", model: "gpt-5.1-codex-mini", env: {
+        OPENAI_API_KEY: { type: "user_secret_ref", key: "OPENAI_API_KEY", version: "latest", required: true } } },
+      runtimeConfig: { heartbeat: { enabled: false, wakeOnDemand: true, maxConcurrentRuns: 50 } },
+    } }));
+    await expect.poll(async () => (await json(await request.get(`/api/agents/${agent.id}`))).lifecycleState,
+      { timeout: 60_000 }).toBe("ready");
+    report.setup = { environmentId: environment.id, agentId: agent.id,
+      selection: "Normal local environment and control agent; existing deterministic Codex leaf command; no resolver override" };
+    const text = ".".repeat(W.prelude - 1) + ` PRELUDE_${nonce}_READY `
+      + Array.from({ length: W.events }, (_, index) => `[${code}${index.toString(36)}] `).join("");
+    expect([...text].length).toBeLessThan(4000);
+    const state = { events: W.events, intervalMs: W.intervalMs, streams: new Map(), errors: [] } as any;
+    state.streams.set(nonce, { nonce, markerCode: code, opened: false, hello: false, ended: false, aborted: false,
+      partialBytes: 0, records: new Map(), expectedLauncher: "host-local" });
+    clock.clocks.set(key, state); clock.pending.set(key, new Map());
+    const prompt = `Measure native streaming for ${nonce.slice(0, 8)}.\n\nINGESTION_PERF nonce=${nonce} events=${W.events} intervalMs=${W.intervalMs} prelude=${W.prelude} markerCode=${code} gate=${clock.base}${key}`;
+    const before = new Set((await json(await request.get(`/api/companies/${company.id}/issues`))).map((row: any) => row.id));
+    await page.goto(`/${company.issuePrefix}/agents/${agent.id}/overview`);
+    await page.getByRole("link", { name: "Tasks", exact: true }).click();
+    await page.getByRole("button", { name: "New Task", exact: true }).last().click();
+    const dialog = page.getByRole("dialog");
+    await dialog.getByRole("textbox", { name: "editable markdown" }).fill(prompt);
+    await dialog.getByRole("button", { name: "Select assignee", exact: true }).click();
+    await page.getByRole("listbox", { name: "Assignees", exact: true }).getByRole("option")
+      .filter({ has: page.getByText(agent.name, { exact: true }) }).click();
+    await expect(dialog.getByRole("button", { name: "Select assignee" })).toContainText(agent.name);
+    report.setup.taskCreateActionAtMs = Date.now();
+    await dialog.getByRole("button", { name: "Create task", exact: true }).click();
+    let issue: any;
+    await expect.poll(async () => {
+      issue = (await json(await request.get(`/api/companies/${company.id}/issues`)))
+        .find((row: any) => !before.has(row.id) && row.description?.includes(nonce)); return Boolean(issue);
+    }).toBe(true);
+    report.issueId = issue.id;
+    await page.goto(`/${company.issuePrefix}/issues/${issue.identifier}`);
+    await expect.poll(() => clock.pending.get(key)!.has(nonce) && state.streams.get(nonce).hello,
+      { timeout: W.readinessMs, intervals: [W.pollIntervalMs] }).toBe(true);
+    await expect(page.getByText(`PRELUDE_${nonce}_READY`, { exact: false }).first()).toBeVisible({ timeout: W.streamMs });
+    let run: any;
+    await expect.poll(async () => {
+      run = (await json(await request.get(`/api/companies/${company.id}/heartbeat-runs?limit=1000`)))
+        .find((row: any) => (row.issueId ?? row.nativeIssueId ?? row.contextSnapshot?.issueId ?? row.contextSnapshot?.taskId) === issue.id);
+      return Boolean(run);
+    }).toBe(true);
+    companyRunId = run.id; report.runId = run.id;
+    const readEvents = async () => {
+      const result: any[] = []; let afterSeq = 0;
+      for (;;) {
+        const rows = await json(await request.get(`/api/heartbeat-runs/${run.id}/events?afterSeq=${afterSeq}&limit=1000`));
+        if (!rows.length) return result;
+        result.push(...rows);
+        const next = Math.max(...rows.map((row: any) => row.seq)); expect(next).toBeGreaterThan(afterSeq); afterSeq = next;
+      }
+    };
+    const prelude = (await readEvents()).map(row => row.payload?.prpEvent)
+      .filter(event => event?.eventType === "item.delta" && String(event.itemId).startsWith("prelude-"));
+    expect(prelude).toHaveLength(W.prelude);
+    prelude.forEach((event, index) => {
+      expect(event.payload.text).toBe(index === W.prelude - 1 ? ` PRELUDE_${nonce}_READY ` : ".");
+      expect(event.sourceInstanceId).toBeTruthy(); expect(event.sourceEventId).toBeTruthy();
+      expect(Number.isSafeInteger(event.sourceSeq) && event.sourceSeq > 0).toBe(true);
+    });
+    expect(new Set(prelude.map(event => `${event.sourceInstanceId}:${event.sourceEventId}:${event.sourceSeq}`)).size).toBe(W.prelude);
+    report.prelude = { individualDeltas: prelude.length, uniqueIdentities: prelude.length, verifiedBeforeEpochAtMs: Date.now(),
+      method: "Normal event API read of actual emitted and committed deltas; no outcome prepopulation" };
+    const authority = await runtimeAuthority({ appRoot, companyId: company.id, environmentId: environment.id,
+      issueIds: [issue.id], transport: "local" });
+    const row = authority.rows[0], stream = state.streams.get(nonce);
+    expect(row.run_id).toBe(run.id);
+    expect(row.process_identity.processPid).toBe(row.process_pid);
+    expect(row.process_identity.processGroupId).toBe(row.process_group_id);
+    const processes = { runner: birth(row.process_pid), provider: birth(stream.providerPid), group: row.process_group_id };
+    expect(processes.runner.group).toBe(processes.group); expect(processes.provider.group).toBe(processes.group);
+    const alive = () => !processAbsent(processes.runner.pid) && !processAbsent(-processes.group) && !processAbsent(processes.provider.pid);
+    expect(alive()).toBe(true); report.authorityBefore = authority; report.processesBefore = processes;
+    state.epochMs = Date.now() + 1000; report.epochMs = state.epochMs;
+    clock.pending.get(key)!.get(nonce)!.writeHead(200, { "Content-Type": "application/json" }).end(JSON.stringify({ epochMs: state.epochMs }));
+    const visible = () => page.evaluate(markerCode => (window as any).nativeIngestionVisible.filter((item: any) => item.markerCode === markerCode), code);
+    await expect.poll(async () => (await visible()).length, { timeout: W.streamMs }).toBeGreaterThanOrEqual(W.visibleBeforeLock);
+    report.visibleBeforeLock = await visible();
+    holder = await ownedDatabase(appRoot, "blocked_stop_owned_lock");
+    observer = await ownedDatabase(appRoot, "blocked_stop_independent_observer");
+    await holder.unsafe("BEGIN"); held = true;
+    const owned = await holder`select id, company_id, pg_backend_pid() as holder_pid from heartbeat_runs
+      where company_id = ${company.id} and id = ${run.id} for update`;
+    expect(owned).toHaveLength(1); const holderPid = owned[0].holder_pid;
+    report.lock = { ...owned[0], acquiredAtMs: Date.now(), scope: "One owned company/run row; no persisted mutation" };
+    await expect.poll(async () => {
+      const rows = await blockers(observer, holderPid);
+      report.appendBlockedBeforeStop = { observedAtMs: Date.now(), rows };
+      return rows.some((candidate: any) => isAppendLockQuery(candidate.query));
+    }, { timeout: 10_000, intervals: [W.pollIntervalMs] }).toBe(true);
+    const button = page.getByRole("button", { name: "Stop", exact: true }); await expect(button).toBeVisible();
+    const stop = page.waitForRequest(req => {
+      const matched = req.method() === "POST" && new URL(req.url()).pathname === `/api/heartbeat-runs/${run.id}/cancel`;
+      if (matched) report.timing.requestAtMs = Date.now();
+      return matched;
+    });
+    report.timing.actionAtMs = Date.now();
+    const click = button.click();
+    stopRequest = await stop; await click;
+    const emissionsAtRequest = stream.records.size;
+    do {
+      const snapshot = await cancellationSnapshot(observer, company.id, run.id);
+      const sample = { ...snapshot, httpPending: !stopSettled, auditIds: snapshot.audits.map((audit: any) => audit.id),
+        processesAlive: alive(), clockOpen: !stream.ended && !stream.aborted,
+        emittedCount: stream.records.size, blockers: await blockers(observer, holderPid) };
+      expect(birth(processes.runner.pid)).toEqual(processes.runner);
+      expect(birth(processes.provider.pid)).toEqual(processes.provider);
+      report.heldSamples.push(sample); assertHeldSample(sample, holderPid);
+      if (Date.now() >= report.timing.requestAtMs + W.heldAfterActualRequestMs) break;
+      await delay(Math.min(W.pollIntervalMs, report.timing.requestAtMs + W.heldAfterActualRequestMs - Date.now()));
+    } while (true);
+    expect(stream.records.size, "Real provider continues emitting while transcript writes and Stop await the run lock").toBeGreaterThan(emissionsAtRequest);
+    report.timing.releaseRequestedAtMs = Date.now();
+    await holder.unsafe("COMMIT"); held = false; report.timing.releaseCommitAckAtMs = Date.now();
+    let acknowledged = false, absent = false;
+    const observationStartedAtMs = Date.now();
+    const observe = async () => {
+      const snapshot = await cancellationSnapshot(observer, company.id, run.id);
+      if (snapshot.intent) { assertIntentAudit(snapshot); report.intentObserved ??= snapshot; }
+      if (!acknowledged) {
+        const value = snapshot.intent?.dispatchState === "acknowledged";
+        report.observerSamples.push({ kind: "ack-query", startedAtMs: snapshot.queryStartedAtMs,
+          completedAtMs: snapshot.observedAtMs, durationMs: snapshot.observedAtMs - snapshot.queryStartedAtMs, value });
+        if (value) {
+          assertIntentAudit(snapshot); acknowledged = true; report.timing.ackObservedAtMs = snapshot.observedAtMs;
+          report.ack = snapshot; report.timing.ackSuccessfulQueryStartedAtMs = snapshot.queryStartedAtMs;
+        } else report.timing.lastAckNotObservedAtMs = snapshot.observedAtMs;
+      }
+      if (!absent) {
+        const checkStartedAtMs = Date.now();
+        const value = processAbsent(processes.runner.pid) && processAbsent(-processes.group) && processAbsent(processes.provider.pid);
+        const completedAtMs = Date.now();
+        report.observerSamples.push({ kind: "process-check", startedAtMs: checkStartedAtMs,
+          completedAtMs, durationMs: completedAtMs - checkStartedAtMs, value });
+        if (value) {
+          absent = true; report.timing.absenceObservedAtMs = completedAtMs;
+          report.timing.absenceSuccessfulCheckStartedAtMs = checkStartedAtMs;
+          report.processesAfter = { runnerAbsent: true, groupAbsent: true, providerAbsent: true, checkedAtMs: completedAtMs };
+        } else report.timing.lastProcessesPresentAtMs = completedAtMs;
+      }
+    };
+    await observe();
+    const settlement = await observeRunSettlement({ expectedRuns: 1,
+      readRuns: async () => { await observe(); return [await json(await request.get(`/api/heartbeat-runs/${run.id}`))]; },
+      readRun: async () => json(await request.get(`/api/heartbeat-runs/${run.id}`)),
+      poll: (read: () => Promise<boolean>, timeout: number) => expect.poll(read, { timeout, intervals: [W.pollIntervalMs] }).toBe(true),
+      onOutcome: (outcome: unknown) => { report.settlement = outcome; } });
+    expect(settlement.runs[0].status).toBe("cancelled"); report.settledAtMs = Date.now();
+    const sharedDetail = await json(await request.get(`/api/heartbeat-runs/${run.id}`));
+    report.sharedSettlement = { runId: sharedDetail.id, companyId: sharedDetail.companyId, status: sharedDetail.status,
+      cancellation: sharedDetail.resultJson?.cancellation ?? null,
+      executionCancellation: sharedDetail.resultJson?.executionCancellation ?? null,
+      nativeCancellation: sharedDetail.resultJson?.nativeCancellation ?? null, observedAtMs: Date.now() };
+    await expect.poll(async () => { await observe(); return acknowledged; },
+      { timeout: W.acknowledgementAfterSettlementMs, intervals: [W.pollIntervalMs] }).toBe(true);
+    await expect.poll(async () => { await observe(); return absent; },
+      { timeout: W.acknowledgementAfterSettlementMs, intervals: [W.pollIntervalMs] }).toBe(true);
+    report.timing.postReleaseObservationStartedAtMs = observationStartedAtMs;
+    await expect.poll(() => stopSettled, { timeout: W.acknowledgementAfterSettlementMs,
+      intervals: [W.pollIntervalMs] }).toBe(true);
+    const response = await stopRequest.response(); expect(response?.ok()).toBe(true); report.stopHttpStatus = response!.status();
+    report.authorityAfter = await runtimeAuthority({ appRoot, companyId: company.id, environmentId: environment.id,
+      issueIds: [issue.id], transport: "local", afterStop: true });
+    const stopped = report.authorityAfter.rows[0];
+    expect(stopped.status).toBe("cancelled"); expect(stopped.cancellation_dispatch_state).toBe("acknowledged");
+    expect(BigInt(stopped.process_stopped_seq)).toBeGreaterThan(BigInt(row.process_identity_seq));
+    expect(stopped.process_stopped_source_event_id).toBeNull();
+    expect(stopped.process_stopped.processPid).toBe(processes.runner.pid);
+    expect(stopped.process_stopped.processGroupId).toBe(processes.group);
+    let lease: any;
+    await expect.poll(async () => {
+      lease = (await json(await request.get(`/api/environments/${environment.id}/leases`)))
+        .find((candidate: any) => candidate.heartbeatRunId === run.id);
+      return Boolean(lease?.releasedAt && ["released", "expired", "failed"].includes(lease.status) && lease.cleanupStatus !== "failed");
+    }, { timeout: W.leaseAfterSettlementMs }).toBe(true);
+    expect(lease.provider).toBe("local"); expect(lease.providerLeaseId).toBeNull();
+    report.lease = lease;
+    const seen = await visible(), events = await readEvents();
+    const deltas = events.map(event => event.payload?.prpEvent).filter(event => event?.eventType === "item.delta"
+      && String(event.payload?.text).startsWith(`[${code}`));
+    expect(deltas.length).toBeGreaterThanOrEqual(W.visibleBeforeLock);
+    deltas.forEach((event, index) => {
+      expect(event.payload.text).toBe(`[${code}${index.toString(36)}] `); expect(event.runId).toBe(run.id);
+      expect(event.sourceInstanceId).toBeTruthy(); expect(event.sourceEventId).toBeTruthy();
+      expect(Number.isSafeInteger(event.sourceSeq) && event.sourceSeq > 0).toBe(true);
+      expect(stream.records.has(index)).toBe(true);
+    });
+    expect(new Set(deltas.map(event => `${event.sourceInstanceId}:${event.sourceEventId}:${event.sourceSeq}`)).size).toBe(deltas.length);
+    seen.forEach((marker: any) => expect(marker.index).toBeLessThan(deltas.length));
+    expect(events.filter(event => event.eventType === "run.result.accepted" || event.payload?.prpEvent?.eventType === "run.result.accepted")).toHaveLength(0);
+    await page.screenshot({ path: info.outputPath("blocked-stop-existing-history.png"), fullPage: true });
+    await page.reload();
+    await expect(page.getByRole("button", { name: "Stop", exact: true })).toHaveCount(0);
+    await expect(page.getByText(`[${code}${seen.at(-1).index.toString(36)}]`, { exact: false }).first()).toBeVisible();
+    const transcriptRows = (rows: any[]) => rows.filter(row => row.payload?.prpEvent?.eventType === "item.delta")
+      .map(row => ({ id: row.id, seq: row.seq, event: row.payload.prpEvent }));
+    expect(transcriptRows(await readEvents())).toEqual(transcriptRows(events));
+    await expect.poll(() => stream.ended || stream.aborted, { timeout: 30_000 }).toBe(true);
+    expect(state.errors).toEqual([]);
+    report.transcript = { individualDeltas: deltas.length, uniqueSourceIdentities: deltas.length, ordered: true,
+      persistedAfterReload: true, resultAcceptedEvents: 0, seen, deltas, preludeCount: prelude.length };
+    report.clock = { ...stream, records: [...stream.records.values()] };
+    report.complete = true;
+  } catch (error) {
+    report.failure = { message: String(error), stack: error instanceof Error ? error.stack : undefined, atMs: Date.now() };
+    throw error;
+  } finally {
+    const cleanupErrors: unknown[] = [];
+    const cleanup = async (step: string, action: () => Promise<unknown>) => {
+      try { await action(); } catch (error) { cleanupErrors.push({ step, error: String(error) }); }
+    };
+    // Always release our exact owned lock before invoking any public cancellation cleanup.
+    if (held) await cleanup("rollback-owned-lock", async () => { await holder.unsafe("ROLLBACK"); held = false; });
+    if (holder) await cleanup("close-holder", () => holder.end({ timeout: 5 }));
+    if (observer) await cleanup("close-observer", () => observer.end({ timeout: 5 }));
+    for (const pending of clock.pending.values()) for (const response of pending.values()) if (!response.writableEnded) response.writeHead(503).end();
+    clock.gate.closeAllConnections(); await new Promise<void>(resolve => clock.gate.close(() => resolve()));
+    if (companyRunId) await cleanup("settle-owned-run", async () => {
+      const run = await json(await request.get(`/api/heartbeat-runs/${companyRunId}`));
+      if (["running", "queued"].includes(run.status)) await json(await request.post(`/api/heartbeat-runs/${companyRunId}/cancel`));
+    });
+    await cleanup("restore-experimental-settings", async () => json(await request.patch("/api/instance/settings/experimental", {
+      data: { enableNativeRunner: original.enableNativeRunner, enableWorktreeRunExecution: original.enableWorktreeRunExecution } })));
+    report.cleanup = { complete: cleanupErrors.length === 0, errors: cleanupErrors };
+    report.complete &&= report.cleanup.complete; report.finishedAtMs = Date.now();
+    let validationError: unknown;
+    if (report.complete) {
+      try { report.metrics = metrics(report); assertFunctional(report); }
+      catch (error) { validationError = error; report.complete = false; report.validationFailure = String(error); }
+    }
+    await info.attach("native-ingestion-blocked-stop-evidence", { body: JSON.stringify(report, null, 2), contentType: "application/json" });
+    if (validationError) throw validationError;
+    if (!report.failure) expect(cleanupErrors).toEqual([]);
+    page.off("requestfinished", stopFinished); page.off("requestfailed", stopFinished);
+  }
+});
diff --git a/tests/e2e/playwright-native-ingestion-blocked-stop.config.ts b/tests/e2e/playwright-native-ingestion-blocked-stop.config.ts
new file mode 100644
index 00000000000..3446dbe0af1
--- /dev/null
+++ b/tests/e2e/playwright-native-ingestion-blocked-stop.config.ts
@@ -0,0 +1,5 @@
+import { defineConfig } from "@playwright/test";
+import base from "./playwright-native-ingestion.config";
+process.env.PAPERCLIP_INGESTION_COMPANION_PROTOCOL = "blocked-stop-history-v1";
+export default defineConfig({ ...base, testMatch: "native-event-ingestion-blocked-stop.journey.ts", timeout: 900_000,
+  retries: 0, workers: 1, use: { ...base.use, trace: "off", video: "off" } });