diff --git a/packages/paperclip-runner/docs/runner-protocol-live-evals.md b/packages/paperclip-runner/docs/runner-protocol-live-evals.md
index 4c7733d1f6e..03a7d7788b3 100644
--- a/packages/paperclip-runner/docs/runner-protocol-live-evals.md
+++ b/packages/paperclip-runner/docs/runner-protocol-live-evals.md
@@ -311,6 +311,10 @@ The manifest schema is `paperclip.runner-eval.controller/v1`. It contains:
   `requestSha256`, `provider`, optional `acpxAgent`, exact `model`, `maxUsd`,
   `maxRequests`, `maxConcurrent`, and `timeoutMs`. Native Codex and ACPX
   Claude are supported. Each execution has one explicit attempt and no retry.
+- Optional `observability`: an explicit `projectId`, four boolean `capture`
+  switches (`userPrompts`, `assistantResponses`, `toolDetails`, `toolContent`),
+  `nativeLimits`, and a reviewed full-lifecycle `provisionalBound`. When absent,
+  the controller starts no exporter or OTLP relay.
 
 Use `requestBindingSha256` from `controlled-evals/manifest.mjs` to bind the
 complete compiled request. It excludes only the temporary working directory
@@ -407,8 +411,60 @@ This local controller is not yet wired into the hosted matrix. Its durable
 attempt-directory guard applies to one shared filesystem, not independent
 GitHub workers. Hosted integration must bind unique cells to the prepared
 allocation, reject workflow/job reruns, and preserve the controller evidence
-before enabling paid work. Native OTLP routing, report integration, vendor
+before enabling paid work. Hosted tracing, destination readback, vendor
 metering bounds, and actual paid qualification remain separate gates.
+## Controller tracing allocations and retained proof
+
+The opt-in controller uses the existing native launch generator and Product E2E
+OTLP relay. `nativeLimits` must explicitly provide `maxRequests`,
+`maxRequestBytes`, `maxTotalBytes`, `maxConcurrent`, `maxExpandedBytes`, and
+`maxRecords`, each within that relay's supported ceilings. These limits apply
+to each selected attempt, including failed attempts. Each attempt additionally
+reserves one controller root request, at most 16 KiB of source JSON, 64 KiB
+expanded source size, and one record. The root relay has its own credential;
+the provider cannot consume its allocation or change its parent.
+
+Use `observabilityBoundConfiguration(manifest)` from `manifest.mjs` as the
+configuration for the observability `provisionalBound`. It binds the complete
+attempt selection, compiled-request digests, revisions, project, capture,
+native and root capacities, deadline, and operating allowance. Its evidence
+SHA-256 must match the observability operating component's evidence. Changing
+these inputs invalidates the qualification. The reviewed evidence must cover
+the sum of all attempts' native and root capacities and full retention costs;
+source bytes and receiver acceptance do not themselves establish billed bytes,
+price, or a vendor spending cap. This declaration does not activate an allowance.
+
+The controller requires `BRAINTRUST_API_KEY` even when model traffic uses a
+direct provider key. Both upstream credentials stay on the controller. The
+provider receives only its attempt's model and native OTLP tokens. Native
+headers and any payload parent must match the exact assigned attempt parent,
+including when another parent belongs to the same project. Cancellation closes
+both relays, aborts pending forwarding, and retains uncertain outcomes without
+retrying them.
+
+Private archives retain `observability.json`, body-free `otlp-native.jsonl` and
+`otlp-controller.jsonl` receipts, and the metadata-only `otlp-root.json`.
+Offline replay validates allocation, parent, descriptor, payload digests,
+admission/outcome pairs, quotas, closure totals, and the root's identity and
+content after the worker is deleted. Missing, partial, quota-exhausted, poisoned,
+or unfinished export evidence keeps the attempt incomplete with its full model
+allocation held and known model charges preserved. Operating holds remain
+reserved once per campaign. OTLP usage is never added to the model ledger.
+
+`observability.status: "accepted"` requires accepted native log and trace
+records plus the controller root. It describes the retained requests only;
+`verification: "unverified"` remains until separate Braintrust readback.
+Neither field proves complete capture, semantic grading success, or invoice
+settlement. The root links revisions, the compiled request, execution, attempt,
+provider, model, and cleanup status. Native receipts are checked before the root
+is built. Its `controller_status_before_root_export` includes known native export
+failures; the final retained report remains authoritative for root-export failures
+or later cancellation. Cancellation stays connected through root finalization.
+Feedback persistence is explicitly
+unavailable in the Runner mock control plane; it does not report zero complaints
+or suggestions. Actual grading and provider failures remain in the immutable
+Runner artifact.
+
 ## Hosted campaign
 
 Use the `Runner Direct Live Protocol Evals` workflow. Dispatch the workflow
diff --git a/packages/paperclip-runner/scripts/controlled-evals/archive.mjs b/packages/paperclip-runner/scripts/controlled-evals/archive.mjs
index 14194c48d8d..88f77864d44 100644
--- a/packages/paperclip-runner/scripts/controlled-evals/archive.mjs
+++ b/packages/paperclip-runner/scripts/controlled-evals/archive.mjs
@@ -10,6 +10,7 @@ const MiB = 1_048_576;
 const MAX_RAW_BYTES = 64 * MiB;
 const MAX_ARCHIVE_BYTES = 96 * MiB;
 
+
 function secretValues({ environment = process.env, secrets = [] } = {}) {
   const configured = [...secrets, ...Object.entries(environment)
     .filter(([name]) => /(?:KEY|TOKEN|SECRET|PASSWORD|ACCESS_KEY_ID|CONFIG_CONTENT)$/i.test(name))
diff --git a/packages/paperclip-runner/scripts/controlled-evals/controller.test.mjs b/packages/paperclip-runner/scripts/controlled-evals/controller.test.mjs
index 68498bd6bb6..6b374dfea81 100644
--- a/packages/paperclip-runner/scripts/controlled-evals/controller.test.mjs
+++ b/packages/paperclip-runner/scripts/controlled-evals/controller.test.mjs
@@ -1,11 +1,12 @@
 import assert from 'node:assert/strict';
 import { test } from 'node:test';
 import { execFileSync } from 'node:child_process';
-import { mkdtemp, mkdir, readFile, readdir, rm, symlink, truncate, writeFile } from 'node:fs/promises';
+import { mkdtemp, mkdir, open, readFile, readdir, rm, stat, symlink, truncate, writeFile } from 'node:fs/promises';
 import { writeFileSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import { join } from 'node:path';
-import { canonical, costRuntime, requestBindingSha256, sha256, validateManifest } from './manifest.mjs';
+import { fileURLToPath } from 'node:url';
+import { canonical, costRuntime, observabilityBoundConfiguration, requestBindingSha256, sha256, validateManifest } from './manifest.mjs';
 import { attemptDirectory, runControlledEval } from './run.mjs';
 import { summarizeControlledCampaign } from './report.mjs';
 import { readRegularFile, replaceEvidenceFile } from './evidence-files.mjs';
@@ -17,11 +18,12 @@ import assert from 'node:assert/strict';
 import {createHash} from 'node:crypto';
 import {spawn} from 'node:child_process';
 import {once} from 'node:events';
-import {readFile,writeFile,rm,readdir,symlink,truncate} from 'node:fs/promises';
+import {readFile,writeFile,rm,readdir,symlink,truncate,mkdir} from 'node:fs/promises';
 import {dirname,join} from 'node:path';
 import {execFileSync} from 'node:child_process';
 const args=new Map();for(let i=2;i<process.argv.length;i+=2)args.set(process.argv[i],process.argv[i+1]);
 const request=JSON.parse(await readFile(args.get('--request'),'utf8'));
+if(${Boolean(options.failChild)})process.exit(3);
 if(${Boolean(options.resistantDescendant)}) {
  const orphan=${Boolean(options.orphanExit)};
  const descendant=spawn(process.execPath,['-e',"process.on('SIGTERM',()=>{});"+(orphan?"process.send('ready');":"process.stdout.write('ready');")+"setInterval(()=>{},1000)"],{stdio:orphan?['ignore','inherit','inherit','ipc']:['ignore','pipe','ignore']});
@@ -36,11 +38,35 @@ for(let i=0;i<${options.requests ?? 3};i++){
  const response=await fetch(descriptor.baseUrl+(descriptor.provider==='openai'?'/v1/responses':'/v1/messages'),{method:'POST',headers:{authorization:'Bearer '+process.env.PAPERCLIP_RUNNER_EVAL_GATEWAY_TOKEN,'content-type':'application/json'},body:JSON.stringify({model:request.model,input:'synthetic fixture'})});
  statuses.push(response.status);await response.text();
 }
+let nativeObservability;
+if(args.has('--observability-config')) {
+ const raw=await readFile(args.get('--observability-config'),'utf8'),config=JSON.parse(raw);
+ const parent=decodeURIComponent(config.launch.environment.OTEL_EXPORTER_OTLP_TRACES_HEADERS.slice('x-bt-parent='.length));
+ for(const signal of ['logs','traces'])for(let i=0;i<${options.otelRequests ?? 1};i++) {
+  const body=signal==='logs'?{resourceLogs:[{scopeLogs:[{logRecords:[{body:{stringValue:'synthetic-native-content'}}]}]}]}:{resourceSpans:[{scopeSpans:[{spans:[{traceId:'1'.repeat(32),spanId:'2'.repeat(16),name:'synthetic-native-span'}]}]}]};
+  const response=await fetch(config.baseUrl+'/v1/'+signal,{method:'POST',headers:{authorization:'Bearer '+process.env.PAPERCLIP_RUNNER_EVAL_OTLP_TOKEN,'x-bt-parent':parent,'content-type':'application/json'},body:JSON.stringify(body)});
+  await response.arrayBuffer();
+ }
+ nativeObservability={mode:'controller_otlp',configured:true,verification:'unverified',projectId:config.projectId,traceId:config.traceId,spanId:config.spanId,descriptorSha256:createHash('sha256').update(raw).digest('hex')};
+ if(${Boolean(options.realObservabilityValidator)}) {
+  const {createRequire}=await import('node:module');
+  const require=createRequire(${JSON.stringify(fileURLToPath(new URL('../../../../server/package.json', import.meta.url)))});
+  const {tsImport}=await import(require.resolve('tsx/esm/api'));
+  const {prepareEvalObservabilityRuntime}=await tsImport(${JSON.stringify(fileURLToPath(new URL('../../src/cli/eval-observability-runtime.ts', import.meta.url)))},import.meta.url);
+  await mkdir(process.env.HOME+'/codex',{recursive:true});
+  const prepared=await prepareEvalObservabilityRuntime(args.get('--observability-config'),request,
+   {evidence:{campaignId:descriptor.campaignId,executionId:descriptor.executionId},transportOptions:{environment:{CODEX_HOME:process.env.HOME+'/codex'}}},process.env);
+  assert.deepEqual(prepared.evidence,nativeObservability);
+  for(const signal of ['LOGS','TRACES'])assert(prepared.transportOptions.environment['OTEL_EXPORTER_OTLP_'+signal+'_HEADERS'].includes(encodeURIComponent('Bearer '+process.env.PAPERCLIP_RUNNER_EVAL_OTLP_TOKEN)));
+  nativeObservability=prepared.evidence;
+ }
+
+}
 if(${Boolean(options.waitForever)})await new Promise(()=>setInterval(()=>{},1000));
 if(!${Boolean(options.missingArtifact)})await writeFile(args.get('--output'),JSON.stringify({schema:'paperclip-runner/eval-session-artifact/v1',attemptId:request.attemptId,requestedModel:request.model,
  requestRouting:${options.missingRoute ? 'null' : "{mode:'controller_gateway',provider:descriptor.provider,declaredUpstreamRoute:descriptor.upstreamRoute,campaignId:descriptor.campaignId,executionId:descriptor.executionId,attemptId:descriptor.attemptId,descriptorSha256:createHash('sha256').update(descriptorRaw).digest('hex')}"},
- snapshot:{status:'closed',process:{runnerExited:true,runnerPid:process.pid,providerPid:process.pid}},statuses,
- leaked:${options.leakToken ? 'process.env.PAPERCLIP_RUNNER_EVAL_GATEWAY_TOKEN' : 'null'}}));
+ nativeObservability, snapshot:{status:'closed',process:{runnerExited:true,runnerPid:process.pid,providerPid:process.pid}},statuses,
+ leaked:${options.leakToken ? 'process.env.PAPERCLIP_RUNNER_EVAL_GATEWAY_TOKEN' : options.leakOtlpToken ? 'process.env.PAPERCLIP_RUNNER_EVAL_OTLP_TOKEN' : 'null'}}));
 if(${Boolean(options.invalidEvidence)}) {
  const root=dirname(args.get('--output'));
  const name=${JSON.stringify(options.invalidEvidence ?? '')};
@@ -51,6 +77,7 @@ if(${Boolean(options.invalidEvidence)}) {
  else if(kind==='symlink')await symlink('/dev/zero',file);
  else {await writeFile(file,'');await truncate(file,16*1024*1024+1);}
 }
+
 if(${Boolean(options.orphanExit)})process.exit(0);
 `;
 
@@ -82,11 +109,17 @@ async function fixture(t, { count = 1, allocation = '0.01', providerProfile = 'c
     await writeFile(requestPath, JSON.stringify(request)); requests.push({ request, requestPath, outputPath });
     manifest.attempts.push({ executionId: `execution-${index}`, attemptId: request.attemptId, requestSha256: requestBindingSha256(request), provider: request.provider, ...(request.acpxAgent ? { acpxAgent: request.acpxAgent } : {}), model: 'fixture', maxUsd: allocation, maxRequests: 2, maxConcurrent: 1, timeoutMs: 5000 });
   }
+  if (options.observability) {
+    manifest.observability = { projectId: '11111111-1111-4111-8111-111111111111',
+      capture: { userPrompts: false, assistantResponses: false, toolDetails: false, toolContent: false },
+      nativeLimits: { maxRequests: 4, maxRequestBytes: 16384, maxTotalBytes: 32768, maxConcurrent: 1, maxExpandedBytes: 65536, maxRecords: 16 } };
+    manifest.observability.provisionalBound = bound(observabilityBoundConfiguration(manifest));
+  }
   const manifestPath = join(root, 'manifest.json');
   const save = () => writeFile(manifestPath, JSON.stringify(manifest)); await save();
   const environment = { PATH: process.env.PATH, OPENAI_API_KEY: 'synthetic-upstream-private', ANTHROPIC_API_KEY: 'other-private', BRAINTRUST_API_KEY: 'other-braintrust', GH_TOKEN: 'other-github', NODE_OPTIONS: '--require must-not-inherit', PYTHONPATH: '/must-not-inherit' };
   return { root, manifest, manifestPath, requests, environment, save,
-    run: (index = 0, transport = () => success(biller), signal) => runControlledEval({ manifestPath, ...requests[index], environment, transport, signal }) };
+    run: (index = 0, transport = () => success(biller), signal) => runControlledEval({ manifestPath, ...requests[index], environment, transport, signal, otlpTransport: options.otlpTransport ?? (async () => Response.json({})) }) };
 }
 let sequence = 0;
 function success(provider = 'openai') {
@@ -105,7 +138,7 @@ test('real child requests reserve before dispatch, stop at the cap and retain on
     assert.equal(ledger.state.snapshot().inflight, 1);
     return success();
   });
-  assert.equal(calls, 2); assert.equal(result.code, 0); assert.equal(result.report.cleanupVerified, true);
+  assert.equal(calls, 2); assert.equal(result.code, 0, JSON.stringify(result.report)); assert.equal(result.report.cleanupVerified, true);
   const artifact = JSON.parse(await readFile(f.requests[0].outputPath, 'utf8'));
   assert.deepEqual(artifact.statuses, [200, 200, 429]);
   assert.equal(artifact.controllerAccounting.accounting.knownUsd, '0.000136000');
@@ -406,10 +439,10 @@ for (const name of ['provider-artifact.json', 'receipt', 'ledger.jsonl']) for (c
 }
 
 test('durable reports bound every evidence file and retain full holds for invalid proof', { timeout: 20_000 }, async t => {
-  const f = await fixture(t, { requests: 1 }); await f.run();
+  const f = await fixture(t, { requests: 1, observability: true }); await f.run();
   const root = attemptDirectory(f.manifest, 'attempt-0');
   const receipt = `receipts/${(await readdir(join(root, 'receipts')))[0]}`;
-  for (const name of ['admission.json', 'request.json', 'result.json', 'provider-artifact.json', 'gateway.json', 'ledger.jsonl', receipt]) {
+  for (const name of ['admission.json', 'request.json', 'result.json', 'provider-artifact.json', 'gateway.json', 'ledger.jsonl', receipt, 'observability.json', 'otlp-native.jsonl', 'otlp-controller.jsonl', 'otlp-root.json']) {
     const path = join(root, name), original = await readFile(path);
     for (const kind of ['fifo', 'symlink', 'oversized']) {
       await rm(path);
@@ -534,6 +567,148 @@ test('campaign collection retains and audits private archives, while public proj
   await assert.rejects(aggregateProtocolEvalCampaign(input), /Missing private controller evidence/);
 });
 
+for (const providerProfile of ['codex', 'claude']) test(`controller owns native ${providerProfile} trace routing and offline receipts after workspace deletion`, async t => {
+  const received = [];
+  const f = await fixture(t, { providerProfile, observability: true, requests: 1, otlpTransport: async (url, init) => {
+    received.push({ url: String(url), headers: new Headers(init.headers), body: JSON.parse(Buffer.from(init.body).toString()) });
+    return Response.json({});
+  } });
+  const result = await f.run();
+  assert.equal(result.code, 0); assert.equal(received.length, 3);
+  const evidence = result.report.observability;
+  assert.equal(evidence.status, 'accepted'); assert.equal(evidence.verification, 'unverified');
+  assert.equal(evidence.native.admittedRecords, 2); assert.equal(evidence.controller.admittedRecords, 1);
+  assert(received.every(item => item.headers.get('authorization') === 'Bearer other-braintrust'));
+  assert.equal(received[0].headers.get('x-bt-parent'), costRuntime.exportBraintrustAttemptParent(evidence));
+  assert.equal(received[2].headers.get('x-bt-parent'), `project_id:${f.manifest.observability.projectId}`);
+  const root = received[2].body.resourceSpans[0].scopeSpans[0].spans[0];
+  assert.equal(root.traceId, evidence.traceId); assert.equal(root.spanId, evidence.spanId);
+  assert(root.attributes.some(item => item.key === 'paperclip.eval.request_sha256' && item.value.stringValue === f.manifest.attempts[0].requestSha256));
+  assert(!JSON.stringify(root).includes('synthetic-native-content'));
+  const archive = await packControlledAttempt({ manifest: f.manifest, attemptId: 'attempt-0', environment: f.environment });
+  assert(!JSON.stringify(archive).includes('other-braintrust'));
+  await rm(f.manifest.outputDirectory, { recursive: true });
+  await rm(f.requests[0].request.session.workingDirectory, { recursive: true });
+  const summary = await summarizeControlledEvidence([archive]);
+  assert.equal(summary.incompleteAttempts, 0); assert.equal(summary.campaigns[0].attempts[0].observability.status, 'accepted');
+  assert.equal(summary.campaigns[0].operatingHeldUsd, '0.004000000');
+});
+
+test('native capacity, capture, selection and operating bound changes require new qualification', async t => {
+  const f = await fixture(t, { observability: true });
+  for (const mutate of [
+    value => { value.observability.nativeLimits.maxTotalBytes++; },
+    value => { value.observability.capture.userPrompts = true; },
+    value => { value.observability.projectId = '22222222-2222-4222-8222-222222222222'; },
+    value => { value.attempts[0].requestSha256 = 'c'.repeat(64); },
+    value => { value.overhead.components.find(item => item.component === 'observability').provisionalBound.evidenceSha256 = 'c'.repeat(64); },
+    value => { delete value.observability.provisionalBound; },
+  ]) { const manifest = structuredClone(f.manifest); mutate(manifest); assert.throws(() => validateManifest(manifest)); }
+  const noKey = { ...f.environment }; delete noKey.BRAINTRUST_API_KEY;
+  await assert.rejects(runControlledEval({ manifestPath: f.manifestPath, ...f.requests[0], environment: noKey }), /observability credential/);
+  await assert.rejects(readFile(join(f.manifest.outputDirectory, 'admission.json')), { code: 'ENOENT' });
+});
+
+for (const fault of ['partial', 'quota', 'leak']) test(`native ${fault} preserves model cost and holds the unresolved attempt`, async t => {
+  const f = await fixture(t, { observability: true, requests: 1, otelRequests: fault === 'quota' ? 3 : 1,
+    leakOtlpToken: fault === 'leak', otlpTransport: async url => fault === 'partial'
+      ? Response.json({ partialSuccess: String(url).endsWith('/logs') ? { rejectedLogRecords: 1 } : { rejectedSpans: 1 } }) : Response.json({}) });
+  const result = await f.run();
+  assert.equal(result.code, 2); assert.equal(result.report.status, 'incomplete');
+  const summary = await summarizeControlledCampaign(f.manifest);
+  assert.equal(summary.knownUsd, '0.000068000'); assert.equal(summary.committedUsd, '0.014000000');
+  const artifact = JSON.parse(await readFile(f.requests[0].outputPath, 'utf8'));
+  assert.equal(artifact.accountingFailure.retryable, false);
+  if (fault === 'leak') { assert.equal(artifact.leaked, '[redacted]'); assert.equal(result.report.secretExcluded, false); }
+});
+
+test('offline replay refuses lost receipts and forged acceptance even when file hashes are updated', async t => {
+  const f = await fixture(t, { observability: true, requests: 1 }); await f.run();
+  const root = attemptDirectory(f.manifest, 'attempt-0'), path = join(root, 'otlp-native.jsonl');
+  const original = await readFile(path);
+  await rm(path);
+  assert.equal((await summarizeControlledCampaign(f.manifest)).incompleteAttempts, 1);
+  const rows = original.toString().trim().split('\n').map(line => JSON.parse(line));
+  rows.find(row => row.type === 'outcome').outcome = 'partial';
+  const bytes = Buffer.from(rows.map(row => JSON.stringify(row)).join('\n') + '\n');
+  await writeFile(path, bytes);
+  const reportPath = join(root, 'result.json'), report = JSON.parse(await readFile(reportPath, 'utf8'));
+  report.observability.receiptHashes.native = sha256(bytes); await writeFile(reportPath, JSON.stringify(report));
+  const summary = await summarizeControlledCampaign(f.manifest);
+  assert.equal(summary.incompleteAttempts, 1); assert.equal(summary.committedUsd, '0.014000000');
+});
+
+test('cancellation aborts a pending native export and retains its uncertain receipt and model allocation', async t => {
+  const cancellation = new AbortController(); let aborted = false;
+  const f = await fixture(t, { observability: true, requests: 1, otlpTransport: async (_url, init) => {
+    queueMicrotask(() => cancellation.abort());
+    return new Promise((_resolve, reject) => init.signal.addEventListener('abort', () => { aborted = true; reject(new Error('synthetic abort')); }, { once: true }));
+  } });
+  const result = await f.run(0, () => success(), cancellation.signal);
+  assert.equal(result.code, 2); assert.equal(aborted, true); assert.equal(result.report.child.stopped, 'controller_cancelled');
+  const rows = (await readFile(join(attemptDirectory(f.manifest, 'attempt-0'), 'otlp-native.jsonl'), 'utf8')).trim().split('\n').map(line => JSON.parse(line));
+  assert.equal(rows.find(row => row.type === 'outcome').outcome, 'uncertain'); assert.equal(rows.at(-1).type, 'closed');
+  const summary = await summarizeControlledCampaign(f.manifest);
+  assert.equal(summary.knownUsd, '0.000068000'); assert.equal(summary.committedUsd, '0.014000000');
+});
+
+test('lost ledger finalization still closes both OTLP relays', async t => {
+  const f = await fixture(t, { observability: true, requests: 1 });
+  const root = attemptDirectory(f.manifest, 'attempt-0');
+  const result = await f.run(0, async () => { await rm(join(root, 'ledger.jsonl')); return success(); });
+  assert.equal(result.code, 2); assert.equal(result.report.failure, 'ledger_evidence_invalid');
+  assert.equal((await summarizeControlledCampaign(f.manifest)).committedUsd, '0.014000000');
+  for (const file of ['otlp-native.jsonl', 'otlp-controller.jsonl']) {
+    const rows = (await readFile(join(root, file), 'utf8')).trim().split('\n').map(line => JSON.parse(line));
+    assert.equal(rows.at(-1).type, 'closed');
+  }
+  const descriptor = JSON.parse(await readFile(join(root, 'observability.json'), 'utf8'));
+  await assert.rejects(fetch(descriptor.baseUrl + '/v1/logs'));
+});
+
+for (const nativeFault of ['partial', 'quota']) test(`root includes ${nativeFault} native export failure before finalization`, async t => {
+  let rootPayload;
+  const f = await fixture(t, { observability: true, requests: 1, otelRequests: nativeFault === 'quota' ? 3 : 1,
+    otlpTransport: async (url, init) => {
+      if (new Headers(init.headers).get('x-bt-parent').startsWith('project_id:')) {
+        rootPayload = JSON.parse(Buffer.from(init.body).toString()); return Response.json({});
+      }
+      return nativeFault === 'partial' ? Response.json({ partialSuccess: String(url).endsWith('/logs') ? { rejectedLogRecords: 1 } : { rejectedSpans: 1 } }) : Response.json({});
+    } });
+  const result = await f.run();
+  assert.equal(result.code, 2); assert.equal(result.report.observability.traceFailure, 'native_export_incomplete');
+  const attributes = rootPayload.resourceSpans[0].scopeSpans[0].spans[0].attributes;
+  assert(attributes.some(item => item.key === 'paperclip.eval.controller_status_before_root_export' && item.value.stringValue === 'incomplete'));
+});
+
+test('cancellation during root export stops forwarding and cannot close the attempt successfully', async t => {
+  const cancellation = new AbortController(); let rootAborted = false;
+  const f = await fixture(t, { observability: true, requests: 1, otlpTransport: async (_url, init) => {
+    if (!new Headers(init.headers).get('x-bt-parent').startsWith('project_id:')) return Response.json({});
+    queueMicrotask(() => cancellation.abort());
+    return new Promise((_resolve, reject) => init.signal.addEventListener('abort', () => { rootAborted = true; reject(new Error('synthetic root abort')); }, { once: true }));
+  } });
+  const result = await f.run(0, () => success(), cancellation.signal);
+  assert.equal(rootAborted, true); assert.equal(result.code, 2); assert.equal(result.report.failure, 'controller_cancelled');
+  assert.equal(result.report.status, 'incomplete'); assert.equal(result.report.cleanupVerified, true);
+  const root = attemptDirectory(f.manifest, 'attempt-0');
+  const rows = (await readFile(join(root, 'otlp-controller.jsonl'), 'utf8')).trim().split('\n').map(line => JSON.parse(line));
+  assert.equal(rows.find(row => row.type === 'outcome').outcome, 'uncertain'); assert.equal(rows.at(-1).type, 'closed');
+  const summary = await summarizeControlledCampaign(f.manifest);
+  assert.equal(summary.committedUsd, '0.014000000'); assert.equal(summary.knownUsd, '0.000068000');
+});
+
+for (const name of ['observability.json', 'otlp-native.jsonl', 'otlp-controller.jsonl']) for (const kind of ['fifo', 'symlink', 'oversized']) {
+  test(`native post-child ${name} rejects ${kind} and retains model cost plus the full hold`, { timeout: 20_000 }, async t => {
+    const f = await fixture(t, { requests: 1, observability: true, invalidEvidence: name, invalidFileType: kind });
+    const result = await f.run();
+    assert.equal(result.code, 2);
+    const summary = await summarizeControlledCampaign(f.manifest);
+    assert.equal(summary.incompleteAttempts, 1);
+    assert.equal(summary.knownUsd, '0.000068000');
+    assert.equal(summary.committedUsd, '0.014000000');
+  });
+}
 
 test('credential redaction replaces a swapped symlink without changing its target', async t => {
   const f = await fixture(t, { leakToken: true, requests: 0 });
@@ -574,3 +749,69 @@ test('missing provider artifacts cannot bypass immutable result binding', async
   await writeFile(join(directory, 'controller-evidence.json'), JSON.stringify(malformed));
   await assert.rejects(readAttemptControlledEvidence(directory), /Malformed immutable controller result proof/);
 });
+
+
+test('failed final OTLP receipt write returns its saved incomplete report', async t => {
+  const f = await fixture(t, { observability: true, requests: 1 });
+  const root = attemptDirectory(f.manifest, 'attempt-0');
+  const probe = await open(join(f.root, 'prototype-probe'), 'wx');
+  const prototype = Object.getPrototypeOf(probe), original = prototype.writeFile;
+  await probe.close();
+  let failed = false;
+  prototype.writeFile = async function (data, ...options) {
+    if (String(data).includes('"type":"closed"')) {
+      const native = await stat(join(root, 'otlp-native.jsonl')).catch(() => null);
+      if (native && (await this.stat()).ino === native.ino) {
+        failed = true;
+        throw Object.assign(new Error('synthetic final receipt write failure'), { code: 'ENOSPC' });
+      }
+    }
+    return original.call(this, data, ...options);
+  };
+  t.after(() => { prototype.writeFile = original; });
+  const result = await f.run();
+  assert.equal(failed, true); assert.equal(result.code, 2);
+  assert.equal(result.report.status, 'incomplete');
+  assert.deepEqual(JSON.parse(await readFile(join(root, 'result.json'), 'utf8')), result.report);
+  const summary = await summarizeControlledCampaign(f.manifest);
+  assert.equal(summary.knownUsd, '0.000068000'); assert.equal(summary.committedUsd, '0.014000000');
+  const controller = (await readFile(join(root, 'otlp-controller.jsonl'), 'utf8')).trim().split('\n').map(line => JSON.parse(line));
+  assert.equal(controller.at(-1).type, 'closed');
+  const descriptor = JSON.parse(await readFile(join(root, 'observability.json'), 'utf8'));
+  await assert.rejects(fetch(descriptor.baseUrl + '/v1/logs'));
+});
+
+
+for (const providerProfile of ['codex', 'claude']) test(`controller descriptor round trips through the real ${providerProfile} CLI validator`, async t => {
+  const f = await fixture(t, { providerProfile, observability: true, realObservabilityValidator: true, requests: 0 });
+  const result = await f.run();
+  assert.equal(result.code, 0, JSON.stringify(result.report) + '\n' + await readFile(join(attemptDirectory(f.manifest, 'attempt-0'), 'stderr.log'), 'utf8'));
+  assert.equal(result.report.observability.status, 'accepted');
+  const bundle = await packControlledAttempt({ manifest: f.manifest, attemptId: 'attempt-0' });
+  assert.equal((await summarizeControlledEvidence([bundle])).incompleteAttempts, 0);
+});
+
+test('retained failure codes distinguish native startup, child exit and invalid artifacts', async t => {
+  const startup = await fixture(t, { observability: true, requests: 0 });
+  const root = attemptDirectory(startup.manifest, 'attempt-0');
+  const probe = await open(join(startup.root, 'startup-probe'), 'wx');
+  const prototype = Object.getPrototypeOf(probe), original = prototype.sync; await probe.close();
+  let failed = false;
+  prototype.sync = async function (...args) {
+    const native = await stat(join(root, 'otlp-native.jsonl')).catch(() => null);
+    if (native && (await this.stat()).ino === native.ino) {
+      failed = true; throw Object.assign(new Error('synthetic native startup persistence failure'), { code: 'ENOSPC' });
+    }
+    return original.call(this, ...args);
+  };
+  t.after(() => { prototype.sync = original; });
+  const result = await startup.run();
+  prototype.sync = original;
+  assert.equal(failed, true); assert.equal(result.code, 2);
+  assert.equal(result.report.failure, 'observability_start_failed');
+  assert.equal((await summarizeControlledCampaign(startup.manifest)).committedUsd, '0.014000000');
+  const child = await fixture(t, { failChild: true, requests: 0 });
+  assert.equal((await child.run()).report.failure, 'child_failed');
+  const artifact = await fixture(t, { missingRoute: true, requests: 0 });
+  assert.equal((await artifact.run()).report.failure, 'artifact_invalid');
+});
diff --git a/packages/paperclip-runner/scripts/controlled-evals/evidence-files.mjs b/packages/paperclip-runner/scripts/controlled-evals/evidence-files.mjs
index 75b339258c8..14594399a98 100644
--- a/packages/paperclip-runner/scripts/controlled-evals/evidence-files.mjs
+++ b/packages/paperclip-runner/scripts/controlled-evals/evidence-files.mjs
@@ -5,6 +5,7 @@ const MiB = 1_048_576;
 export const FILE_LIMITS = new Map([
   ['admission.json', MiB], ['request.json', 8 * MiB], ['gateway.json', 8192],
   ['ledger.jsonl', 16 * MiB], ['result.json', MiB], ['provider-artifact.json', 16 * MiB],
+  ['observability.json', 131_072], ['otlp-native.jsonl', 2 * MiB], ['otlp-controller.jsonl', 2 * MiB], ['otlp-root.json', 16_384],
   ['stdout.log', MiB], ['stderr.log', MiB],
 ]);
 export const RECEIPT = /^receipts\/[a-f0-9]{8}(?:-[a-f0-9]{4}){3}-[a-f0-9]{12}\.json$/;
diff --git a/packages/paperclip-runner/scripts/controlled-evals/manifest.mjs b/packages/paperclip-runner/scripts/controlled-evals/manifest.mjs
index ba1070a4b06..1c437cd0f1e 100644
--- a/packages/paperclip-runner/scripts/controlled-evals/manifest.mjs
+++ b/packages/paperclip-runner/scripts/controlled-evals/manifest.mjs
@@ -34,7 +34,7 @@ export async function readJson(file, maximum = 1_048_576) {
 }
 export function validateManifest(value, now = Date.now(), { admission = true } = {}) {
   fields(value, ['schema', 'campaignId', 'maxUsd', 'deadlineAt', 'pricingVerifiedAt', 'pricingExpiresAt', 'overhead',
-    'sourceRevision', 'definitionsRevision', 'runnerCli', 'runnerPackage', 'runnerd', 'outputDirectory', 'route', 'projectId', 'models', 'attempts']);
+    'sourceRevision', 'definitionsRevision', 'runnerCli', 'runnerPackage', 'runnerd', 'outputDirectory', 'route', 'projectId', 'models', 'attempts', 'observability']);
   const deadline = Date.parse(value.deadlineAt);
   const verified = Date.parse(value.pricingVerifiedAt), expires = Date.parse(value.pricingExpiresAt);
   if (value.schema !== 'paperclip.runner-eval.controller/v1' || !id(value.campaignId)
@@ -81,6 +81,7 @@ export function validateManifest(value, now = Date.now(), { admission = true } =
     attempts.add(attempt.attemptId); executions.add(attempt.executionId); allocated += units(attempt.maxUsd);
   }
   if (allocated > units(value.maxUsd)) throw new Error('Controlled allocations exceed the campaign budget');
+  validateObservability(value);
   return { manifest: structuredClone(value), manifestSha256: sha256(canonical(value)), allocatedUsd: usd(allocated), overheadUsd: usd(overhead) };
 }
 export function bindRequest(manifest, request) {
@@ -91,3 +92,28 @@ export function bindRequest(manifest, request) {
       || request.runnerd.path !== manifest.runnerd.path) throw new Error('Controlled request does not match its allocated identity');
   return attempt;
 }
+
+export const ROOT_OTLP_LIMITS = Object.freeze({ maxRequests: 1, maxRequestBytes: 16_384, maxTotalBytes: 16_384,
+  maxConcurrent: 1, maxExpandedBytes: 65_536, maxRecords: 1 });
+export function observabilityBoundConfiguration(manifest) {
+  const policy = manifest.observability;
+  return { schema: 'paperclip.runner-eval.observability-bound/v1', campaignId: manifest.campaignId, deadlineAt: manifest.deadlineAt,
+    sourceRevision: manifest.sourceRevision, definitionsRevision: manifest.definitionsRevision,
+    projectId: policy.projectId, capture: policy.capture, nativeLimits: policy.nativeLimits, rootLimits: ROOT_OTLP_LIMITS,
+    attempts: manifest.attempts.map(({ executionId, attemptId, requestSha256 }) => ({ executionId, attemptId, requestSha256 })),
+    overhead: manifest.overhead };
+}
+function validateObservability(manifest) {
+  const policy = manifest.observability;
+  if (policy === undefined) return;
+  fields(policy, ['projectId', 'capture', 'nativeLimits', 'provisionalBound']);
+  fields(policy.capture, ['userPrompts', 'assistantResponses', 'toolDetails', 'toolContent']);
+  if (!/^[a-f0-9]{8}(?:-[a-f0-9]{4}){3}-[a-f0-9]{12}$/i.test(policy.projectId ?? '')
+      || manifest.route === 'braintrust' && policy.projectId !== manifest.projectId
+      || Object.keys(policy.capture).length !== 4 || Object.values(policy.capture).some(value => typeof value !== 'boolean')
+      || canonical(Object.keys(policy.nativeLimits ?? {}).sort()) !== canonical(Object.keys(costRuntime.EVAL_OTLP_LIMITS).sort())
+      || Object.entries(costRuntime.EVAL_OTLP_LIMITS).some(([key, max]) => !Number.isSafeInteger(policy.nativeLimits[key]) || policy.nativeLimits[key] < 1 || policy.nativeLimits[key] > max)) throw new Error('Invalid controller observability allocation');
+  const operating = manifest.overhead.components.find(item => item.component === 'observability');
+  if (!operating || policy.provisionalBound?.evidenceSha256 !== operating.provisionalBound?.evidenceSha256) throw new Error('Observability capacity requires its operating bound evidence');
+  costRuntime.reservationBound('operating_allowance', policy.provisionalBound, observabilityBoundConfiguration(manifest));
+}
diff --git a/packages/paperclip-runner/scripts/controlled-evals/observability.mjs b/packages/paperclip-runner/scripts/controlled-evals/observability.mjs
new file mode 100644
index 00000000000..0bb3d142fdd
--- /dev/null
+++ b/packages/paperclip-runner/scripts/controlled-evals/observability.mjs
@@ -0,0 +1,110 @@
+import { randomBytes } from 'node:crypto';
+import { writeFile } from 'node:fs/promises';
+import { join } from 'node:path';
+import { limitFor, readRegularFile } from './evidence-files.mjs';
+import { canonical, costRuntime, ROOT_OTLP_LIMITS, sha256 } from './manifest.mjs';
+
+function launchFor(manifest, request, identity, baseUrl) {
+  const state = new costRuntime.CapabilityMockControlPlaneAdapter(request.session.seed).snapshot();
+  return costRuntime.buildProviderObservabilityLaunch({ kind: request.provider === 'codex' ? 'codex' : 'claude',
+    companyId: request.session.companyId ?? state.company.id, agentId: request.session.actorId ?? state.actors[0].id,
+    compatibilityKey: identity.traceId, revision: identity.traceId, enabled: true, capture: manifest.observability.capture,
+    logsEndpoint: `${baseUrl}/v1/logs`, tracesEndpoint: `${baseUrl}/v1/traces`,
+    headers: { 'x-bt-parent': costRuntime.exportBraintrustAttemptParent(identity) } });
+}
+const policyFor = (manifest, attempt, identity, deadlineAt, native) => ({ projectId: manifest.observability.projectId,
+  campaignId: manifest.campaignId, attemptId: attempt.attemptId, deadlineAt: new Date(deadlineAt).toISOString(),
+  limits: native ? manifest.observability.nativeLimits : ROOT_OTLP_LIMITS,
+  expectedParent: native ? costRuntime.exportBraintrustAttemptParent(identity) : `project_id:${identity.projectId}` });
+function rootTrace(manifest, attempt, identity, startedAt, finishedAt, cleanupVerified, failure) {
+  const attributes = {
+    'paperclip.eval.family': 'runner_protocol', 'paperclip.eval.campaign_id': manifest.campaignId,
+    'paperclip.eval.execution_id': attempt.executionId, 'paperclip.eval.attempt_id': attempt.attemptId,
+    'paperclip.eval.source_revision': manifest.sourceRevision, 'paperclip.eval.definitions_revision': manifest.definitionsRevision,
+    'paperclip.eval.request_sha256': attempt.requestSha256, 'paperclip.eval.provider': attempt.provider,
+    'paperclip.eval.profile': attempt.acpxAgent ?? attempt.provider, 'paperclip.eval.model': attempt.model,
+    'paperclip.eval.controller_status_before_root_export': failure ? 'incomplete' : 'closed',
+    'paperclip.eval.cleanup_verified': String(cleanupVerified), 'paperclip.eval.feedback_persistence': 'unavailable_mock_control_plane',
+    'paperclip.eval.grading': 'retained_artifact_separate',
+  };
+  return { resourceSpans: [{ resource: { attributes: [{ key: 'service.name', value: { stringValue: 'paperclip-runner-evals' } }] },
+    scopeSpans: [{ scope: { name: 'paperclip.runner-eval-controller', version: '1' }, spans: [{ traceId: identity.traceId, spanId: identity.spanId,
+      name: 'paperclip.runner.eval.attempt', kind: 1, startTimeUnixNano: String(BigInt(Date.parse(startedAt)) * 1_000_000n),
+      endTimeUnixNano: String(BigInt(Date.parse(finishedAt)) * 1_000_000n),
+      attributes: Object.entries(attributes).map(([key, value]) => ({ key, value: { stringValue: value } })) }] }] }] };
+}
+const nativeEvidence = (identity, descriptorSha256) => ({ mode: 'controller_otlp', configured: true, verification: 'unverified', ...identity, descriptorSha256 });
+
+export async function startControlledObservability({ manifest, attempt, request, root, apiKey, deadlineAt, startedAt, transport, signal }) {
+  const identity = { projectId: manifest.observability.projectId, traceId: randomBytes(16).toString('hex'), spanId: randomBytes(8).toString('hex') };
+  let native, controller;
+  const onAbort = () => { void close().catch(() => {}); };
+  const close = async () => {
+    signal?.removeEventListener('abort', onAbort);
+    const results = await Promise.allSettled([native?.close(), controller?.close()]);
+    if (results.some(result => result.status === 'rejected')) throw new Error('OTLP closure unverified');
+  };
+  try {
+    signal?.throwIfAborted();
+    native = await costRuntime.startEvalOtlpRelay({ ...policyFor(manifest, attempt, identity, deadlineAt, true), deadlineAt, apiKey,
+      receiptPath: join(root, 'otlp-native.jsonl'), transport });
+    controller = await costRuntime.startEvalOtlpRelay({ ...policyFor(manifest, attempt, identity, deadlineAt, false), deadlineAt, apiKey,
+      receiptPath: join(root, 'otlp-controller.jsonl'), transport });
+    signal?.addEventListener('abort', onAbort, { once: true });
+    signal?.throwIfAborted();
+    const descriptor = { schema: 'paperclip.runner-eval.observability/v1', campaignId: manifest.campaignId, executionId: attempt.executionId,
+      attemptId: attempt.attemptId, ...identity, baseUrl: native.baseUrl, launch: launchFor(manifest, request, identity, native.baseUrl) };
+    const raw = JSON.stringify(descriptor) + '\n';
+    const descriptorPath = join(root, 'observability.json');
+    await writeFile(descriptorPath, raw, { flag: 'wx', mode: 0o600 });
+    let finished;
+    return { descriptorPath, token: native.token, secrets: [native.token, controller.token],
+      expectedEvidence: nativeEvidence(identity, sha256(raw)), close, closeNative: native.close,
+      finish: input => finished ??= (async () => {
+        const finishedAt = new Date().toISOString();
+        let traceFailure = input.failure;
+        try {
+          await native.close();
+          signal?.throwIfAborted();
+          try {
+            const receipts = costRuntime.inspectEvalOtlpReceipts(await readRegularFile(join(root, 'otlp-native.jsonl'), limitFor('otlp-native.jsonl')),
+              policyFor(manifest, attempt, identity, deadlineAt, true));
+            if (receipts.status !== 'accepted' || !receipts.signals.logs.records || !receipts.signals.traces.records) traceFailure ??= 'native_export_incomplete';
+          } catch { traceFailure ??= 'native_evidence_incomplete'; }
+          const body = JSON.stringify(rootTrace(manifest, attempt, identity, startedAt, finishedAt, input.cleanupVerified, traceFailure));
+          await writeFile(join(root, 'otlp-root.json'), body, { flag: 'wx', mode: 0o600 });
+          const response = await fetch(`${controller.baseUrl}/v1/traces`, { method: 'POST', redirect: 'error',
+            signal: AbortSignal.any([...(signal ? [signal] : []), AbortSignal.timeout(Math.max(1, Math.min(10_000, deadlineAt - Date.now())))]),
+            headers: { authorization: `Bearer ${controller.token}`, 'content-type': 'application/json', 'x-bt-parent': `project_id:${identity.projectId}` }, body });
+          await response.arrayBuffer();
+        } finally { await close(); }
+        return inspectControlledObservability({ manifest, attempt, request, artifact: input.artifact,
+          report: { startedAt, traceFinishedAt: finishedAt, cleanupVerified: input.cleanupVerified, traceFailure },
+          deadlineAt, readEvidence: name => readRegularFile(join(root, name), limitFor(name)) });
+      })() };
+  } catch (error) { await close(); throw error; }
+}
+
+export async function inspectControlledObservability({ manifest, attempt, request, artifact, report, deadlineAt, readEvidence }) {
+  const descriptorBytes = await readEvidence('observability.json');
+  if (descriptorBytes.length > 131_072) throw new Error('Oversized observability descriptor');
+  const descriptor = JSON.parse(descriptorBytes.toString('utf8'));
+  const identity = { projectId: descriptor.projectId, traceId: descriptor.traceId, spanId: descriptor.spanId };
+  if (!/^http:\/\/127\.0\.0\.1:[1-9][0-9]{0,4}\/otel$/.test(descriptor.baseUrl) || Number(new URL(descriptor.baseUrl).port) > 65535
+      || descriptor.projectId !== manifest.observability.projectId || canonical(descriptor) !== canonical({
+        schema: 'paperclip.runner-eval.observability/v1', campaignId: manifest.campaignId, executionId: attempt.executionId, attemptId: attempt.attemptId,
+        ...identity, baseUrl: descriptor.baseUrl, launch: launchFor(manifest, request, identity, descriptor.baseUrl) })
+      || canonical(artifact?.nativeObservability) !== canonical(nativeEvidence(identity, sha256(descriptorBytes)))) throw new Error('Native observability identity or configuration mismatch');
+  const bytes = { native: await readEvidence('otlp-native.jsonl'), controller: await readEvidence('otlp-controller.jsonl'), root: await readEvidence('otlp-root.json') };
+  const native = costRuntime.inspectEvalOtlpReceipts(bytes.native, policyFor(manifest, attempt, identity, deadlineAt, true));
+  const controller = costRuntime.inspectEvalOtlpReceipts(bytes.controller, policyFor(manifest, attempt, identity, deadlineAt, false));
+  if (!Number.isFinite(Date.parse(report.traceFinishedAt)) || Date.parse(report.traceFinishedAt) < Date.parse(report.startedAt)
+      || bytes.root.length > ROOT_OTLP_LIMITS.maxRequestBytes || bytes.root.toString('utf8') !== JSON.stringify(rootTrace(manifest, attempt, identity,
+        report.startedAt, report.traceFinishedAt, report.cleanupVerified, report.traceFailure))) throw new Error('Controller root trace mismatch');
+  const rootRows = bytes.controller.toString('utf8').trim().split('\n').map(line => JSON.parse(line));
+  if (rootRows.filter(row => row.type === 'admitted').length !== 1 || !rootRows.some(row => row.type === 'admitted' && row.payloadSha256 === sha256(bytes.root))) throw new Error('Controller root trace receipt missing');
+  return { ...identity, verification: 'unverified', status: native.status === 'accepted' && controller.status === 'accepted'
+      && native.signals.logs.records > 0 && native.signals.traces.records > 0 && controller.signals.traces.records === 1 ? 'accepted' : 'incomplete',
+    descriptorSha256: sha256(descriptorBytes), native, controller, receiptHashes: { native: sha256(bytes.native), controller: sha256(bytes.controller), root: sha256(bytes.root) },
+    traceFinishedAt: report.traceFinishedAt, traceFailure: report.traceFailure };
+}
diff --git a/packages/paperclip-runner/scripts/controlled-evals/report.mjs b/packages/paperclip-runner/scripts/controlled-evals/report.mjs
index c7cb1664347..b3614f1b72a 100644
--- a/packages/paperclip-runner/scripts/controlled-evals/report.mjs
+++ b/packages/paperclip-runner/scripts/controlled-evals/report.mjs
@@ -1,6 +1,7 @@
 import { join, resolve } from 'node:path';
 import { pathToFileURL } from 'node:url';
 import { canonical, costRuntime, readJson, requestBindingSha256, sha256, units, usd, validateManifest } from './manifest.mjs';
+import { inspectControlledObservability } from './observability.mjs';
 import { attemptDirectory } from './run.mjs';
 import { limitFor, readRegularFile } from './evidence-files.mjs';
 
@@ -23,7 +24,7 @@ export async function summarizeControlledCampaign(value, { filesByAttempt } = {}
       if (bytes.length > maximum) throw new Error('Controller document exceeds its byte limit');
       return JSON.parse(bytes.toString('utf8'));
     };
-    let snapshot, report, verified = false;
+    let snapshot, report, observability, verified = false;
     try {
       const ledgerBytes = await readEvidence('ledger.jsonl');
       const ledger = costRuntime.parseEvalCostLedger(ledgerBytes.toString('utf8'));
@@ -59,6 +60,11 @@ export async function summarizeControlledCampaign(value, { filesByAttempt } = {}
       const artifact = JSON.parse(artifactBytes.toString('utf8'));
       const descriptorBytes = await readEvidence('gateway.json');
       const descriptor = JSON.parse(descriptorBytes.toString('utf8'));
+      if (manifest.observability) {
+        observability = await inspectControlledObservability({ manifest, attempt: allocation, request, artifact,
+          report: { ...report, traceFinishedAt: report.observability?.traceFinishedAt, traceFailure: report.observability?.traceFailure }, deadlineAt: ledgerDeadline, readEvidence });
+        if (canonical(observability) !== canonical(report.observability) || observability.status !== 'accepted') throw new Error('Incomplete controller observability evidence');
+      } else if (artifact.nativeObservability || report.observability) throw new Error('Unallocated observability evidence');
       if (report.schema !== 'paperclip.runner-eval.control-result/v1' || report.manifestSha256 !== manifestSha256
           || report.campaignId !== manifest.campaignId || report.executionId !== allocation.executionId || report.attemptId !== allocation.attemptId
           || report.requestSha256 !== allocation.requestSha256 || report.ledgerSha256 !== sha256(ledgerBytes)
@@ -81,6 +87,7 @@ export async function summarizeControlledCampaign(value, { filesByAttempt } = {}
     const commitment = verified ? observedCommitment : observedCommitment > units(allocation.maxUsd) ? observedCommitment : units(allocation.maxUsd);
     known += cost; committed += commitment;
     attempts.push({ executionId: allocation.executionId, attemptId: allocation.attemptId, status: verified ? 'retained' : 'incomplete',
+      ...(manifest.observability ? { observability: observability ?? { status: 'incomplete', verification: 'unverified' } } : {}),
       allocationUsd: allocation.maxUsd, knownUsd: usd(cost), heldUsd: usd(commitment - cost), committedUsd: usd(commitment),
       unknownRequests: snapshot?.unknownRequests ?? null, boundedUnresolvedRequests: snapshot?.boundedUnresolvedRequests ?? null });
   }
diff --git a/packages/paperclip-runner/scripts/controlled-evals/run.mjs b/packages/paperclip-runner/scripts/controlled-evals/run.mjs
index 48187a8991e..5389b2dba23 100644
--- a/packages/paperclip-runner/scripts/controlled-evals/run.mjs
+++ b/packages/paperclip-runner/scripts/controlled-evals/run.mjs
@@ -4,6 +4,7 @@ import { lstat, mkdir, open, readFile, realpath, rename, rm, writeFile } from 'n
 import { dirname, isAbsolute, join, relative, resolve, sep } from 'node:path';
 import { pathToFileURL } from 'node:url';
 import { parseArgs } from 'node:util';
+import { startControlledObservability } from './observability.mjs';
 import { limitFor, readRegularFile, replaceEvidenceFile } from './evidence-files.mjs';
 import { bindRequest, canonical, costRuntime, readJson, sha256, validateManifest } from './manifest.mjs';
 
@@ -18,7 +19,8 @@ const absent = pid => { try { process.kill(pid, 0); return false; } catch (error
 export const attemptDirectory = (manifest, attemptId) => join(manifest.outputDirectory, sha256(attemptId));
 
 async function runChild(input) {
-  const child = spawn(process.execPath, ['--import', input.loader, input.cli, '--request', input.requestPath, '--output', input.artifactPath, '--gateway-config', input.descriptorPath], {
+  const child = spawn(process.execPath, ['--import', input.loader, input.cli, '--request', input.requestPath, '--output', input.artifactPath, '--gateway-config', input.descriptorPath,
+    ...(input.observabilityPath ? ['--observability-config', input.observabilityPath] : [])], {
     cwd: input.cwd, env: input.environment, detached: true, stdio: ['ignore', 'pipe', 'pipe'],
   });
   let stopped = null, force, escalation;
@@ -61,7 +63,7 @@ export function controlledResultArtifact(artifact, report, attempt) {
     controllerAccounting: report };
 }
 
-export async function runControlledEval({ manifestPath, requestPath, outputPath, environment = process.env, signal, transport }) {
+export async function runControlledEval({ manifestPath, requestPath, outputPath, environment = process.env, signal, transport, otlpTransport }) {
   if (!['linux', 'darwin'].includes(process.platform)) throw new Error('Controlled eval process ownership requires Linux or macOS');
   signal?.throwIfAborted();
   const { manifest, manifestSha256 } = validateManifest(await readJson(manifestPath));
@@ -83,6 +85,8 @@ export async function runControlledEval({ manifestPath, requestPath, outputPath,
   const keyName = manifest.route === 'braintrust' ? 'BRAINTRUST_API_KEY' : provider === 'openai' ? 'OPENAI_API_KEY' : 'ANTHROPIC_API_KEY';
   const key = environment[keyName];
   if (!key || /[\r\n]/.test(key)) throw new Error('Missing controlled eval upstream credential');
+  const observabilityKey = manifest.observability ? environment.BRAINTRUST_API_KEY : undefined;
+  if (manifest.observability && (!observabilityKey || /[\r\n]/.test(observabilityKey))) throw new Error('Missing controlled observability credential');
   const model = manifest.models.find(item => item.provider === provider && item.price.model === attempt.model);
   const root = attemptDirectory(manifest, attempt.attemptId);
   await mkdir(manifest.outputDirectory, { recursive: true, mode: 0o700 });
@@ -115,12 +119,14 @@ registerHooks({ resolve(specifier, context, nextResolve) {
   await mkdir(join(root, 'tmp'), { mode: 0o700 });
   const ledgerPath = join(root, 'ledger.jsonl');
   const ledger = await costRuntime.openEvalCostLedger(ledgerPath, limits);
-  let gateway, child, artifact, failure = null, cleanupVerified = false, secretExcluded = true;
-  let providerArtifactSha256;
-  const secrets = [key];
+  let gateway, observability, observabilityEvidence, child, artifact, failure = null, cleanupVerified = false, secretExcluded = true;
+  let providerArtifactSha256, failureStage = 'controlled_attempt_incomplete';
+  const secrets = [...new Set([key, observabilityKey].filter(Boolean))];
   const redact = raw => secrets.reduce((text, secret) => text.split(secret).join('[redacted]'), raw);
   try {
+    failureStage = 'request_admission_failed';
     await ledger.admitAttempt(attempt.executionId, attempt.attemptId);
+    failureStage = 'gateway_start_failed';
     gateway = await costRuntime.startEvalGateway({ ledger, identity: { executionId: attempt.executionId, attemptId: attempt.attemptId, phase: 'agent' },
       route: { ...model, mode: manifest.route, projectId: manifest.projectId, endpointName: provider === 'openai' ? 'OPENAI_API_KEY' : 'ANTHROPIC_API_KEY', apiKey: key },
       deadlineAt, transport, persist: receipt => atomicJson(join(root, 'receipts', `${receipt.requestId}.json`), receipt),
@@ -129,15 +135,25 @@ registerHooks({ resolve(specifier, context, nextResolve) {
     const descriptor = { schema: 'paperclip.runner-eval.gateway/v1', provider, model: attempt.model, baseUrl: gateway.baseUrl,
       campaignId: manifest.campaignId, executionId: attempt.executionId, attemptId: attempt.attemptId, upstreamRoute: manifest.route };
     const descriptorPath = join(root, 'gateway.json'), descriptorRaw = JSON.stringify(descriptor) + '\n';
+    failureStage = 'gateway_descriptor_failed';
     await writeFile(descriptorPath, descriptorRaw, { flag: 'wx', mode: 0o600 });
     const childEnvironment = Object.fromEntries(['PATH', 'LANG', 'LANGUAGE', 'LC_ALL', 'TZ'].flatMap(name => environment[name] === undefined ? [] : [[name, environment[name]]]));
     Object.assign(childEnvironment, { HOME: join(root, 'home'), TMPDIR: join(root, 'tmp'), TMP: join(root, 'tmp'), TEMP: join(root, 'tmp'), PAPERCLIP_RUNNER_EVAL_GATEWAY_TOKEN: gateway.token });
+    if (manifest.observability) {
+      failureStage = 'observability_start_failed';
+      observability = await startControlledObservability({ manifest, attempt, request, root, apiKey: observabilityKey, deadlineAt, startedAt, transport: otlpTransport, signal });
+      secrets.push(...observability.secrets);
+      childEnvironment.PAPERCLIP_RUNNER_EVAL_OTLP_TOKEN = observability.token;
+    }
     const artifactPath = join(root, 'provider-artifact.json');
+    failureStage = 'child_failed';
     signal?.throwIfAborted();
     if (Date.now() >= deadlineAt) throw new Error('Controlled attempt deadline reached before spawn');
-    child = await runChild({ cli: stagedCli, loader, requestPath: retainedRequestPath, artifactPath, descriptorPath,
-      cwd: request.session.workingDirectory ?? root, environment: childEnvironment, deadlineAt, signal, closeGateway: () => gateway.close() });
+    child = await runChild({ cli: stagedCli, loader, requestPath: retainedRequestPath, artifactPath, descriptorPath, observabilityPath: observability?.descriptorPath,
+      cwd: request.session.workingDirectory ?? root, environment: childEnvironment, deadlineAt, signal, closeGateway: () => Promise.all([gateway.close(), observability?.close()]) });
+    failureStage = 'output_retention_failed';
     for (const stream of ['stdout', 'stderr']) await writeFile(join(root, `${stream}.log`), redact(child[stream]), { flag: 'wx', mode: 0o600 });
+    failureStage = child.code === 0 ? 'artifact_invalid' : 'child_failed';
     const raw = (await readRegularFile(artifactPath, limitFor('provider-artifact.json'))).toString('utf8');
     secretExcluded = secrets.every(secret => !raw.includes(secret));
     if (!secretExcluded) await replaceEvidenceFile(artifactPath, redact(raw));
@@ -146,6 +162,8 @@ registerHooks({ resolve(specifier, context, nextResolve) {
     const expected = { mode: 'controller_gateway', provider, declaredUpstreamRoute: manifest.route, campaignId: manifest.campaignId,
       executionId: attempt.executionId, attemptId: attempt.attemptId, descriptorSha256: sha256(descriptorRaw) };
     if (canonical(artifact.requestRouting) !== canonical(expected) || artifact.attemptId !== attempt.attemptId || artifact.requestedModel !== attempt.model) throw new Error('Provider did not retain the assigned route');
+    if (observability && canonical(artifact.nativeObservability) !== canonical(observability.expectedEvidence)) throw new Error('Provider did not retain the assigned observability route');
+    failureStage = 'provider_cleanup_or_credential_unverified';
     const processInfo = artifact.snapshot?.process;
     const pids = [...new Set([child.pid, processInfo?.runnerPid, processInfo?.providerPid, processInfo?.sidecarPid, processInfo?.agentPid].filter(pid => Number.isSafeInteger(pid) && pid > 0))];
     cleanupVerified = !child.stopped && artifact.snapshot?.status === 'closed' && processInfo?.runnerExited === true
@@ -153,34 +171,46 @@ registerHooks({ resolve(specifier, context, nextResolve) {
       && Number.isSafeInteger(processInfo.providerPid) && processInfo.providerPid > 0 && pids.every(absent);
     if (!cleanupVerified || !secretExcluded) throw new Error('Controlled provider cleanup or credential exclusion is unverified');
   } catch {
-    failure = 'controlled_attempt_incomplete';
+    failure = failureStage;
   } finally {
     try { await gateway?.close(); } catch { failure = 'gateway_cleanup_unverified'; }
     try { await ledger.close(); } catch { failure = 'ledger_close_failed'; }
+    try { await observability?.closeNative(); } catch { failure ??= 'observability_cleanup_unverified'; }
   }
-  if (cleanupVerified) {
-    try { await rm(executables, { recursive: true }); }
-    catch { cleanupVerified = false; failure ??= 'executable_cleanup_unverified'; }
-  }
-  const snapshot = ledger.snapshot();
-  if (snapshot.overBudget || snapshot.conflictingRequests || snapshot.inflight || snapshot.unknownRequests !== snapshot.boundedUnresolvedRequests) failure ??= 'request_accounting_unbounded';
-  const receiptHashes = {};
   try {
-    for (const request of snapshot.requests) receiptHashes[request.requestId] = sha256(await readRegularFile(join(root, 'receipts', `${request.requestId}.json`), limitFor(`receipts/${request.requestId}.json`)));
-  } catch { failure ??= 'request_receipt_missing'; }
-  let ledgerSha256;
-  try { ledgerSha256 = sha256(await readRegularFile(ledgerPath, limitFor('ledger.jsonl'))); }
-  catch { failure ??= 'ledger_evidence_invalid'; }
-  const report = { schema: 'paperclip.runner-eval.control-result/v1', campaignId: manifest.campaignId, manifestSha256,
-    executionId: attempt.executionId, attemptId: attempt.attemptId, requestSha256: attempt.requestSha256,
-    allocationUsd: attempt.maxUsd, limits, startedAt, finishedAt: new Date().toISOString(), status: failure ? 'incomplete' : 'closed', failure,
-    child: child ? { code: child.code, signal: child.signal, stopped: child.stopped } : null,
-    cleanupVerified, secretExcluded, providerArtifactSha256, ledgerSha256, receiptHashes, accounting: snapshot };
-  await atomicJson(join(root, 'result.json'), report);
-  const resultArtifact = controlledResultArtifact(artifact, report, attempt);
-  await mkdir(dirname(resolve(outputPath)), { recursive: true, mode: 0o700 });
-  await writeFile(outputPath, JSON.stringify(resultArtifact, null, 2) + '\n', { flag: 'wx', mode: 0o600 });
-  return { code: failure ? 2 : child?.code ?? 2, report };
+    if (cleanupVerified) {
+      try { await rm(executables, { recursive: true }); }
+      catch { cleanupVerified = false; failure ??= 'executable_cleanup_unverified'; }
+    }
+    const snapshot = ledger.snapshot();
+    if (snapshot.overBudget || snapshot.conflictingRequests || snapshot.inflight || snapshot.unknownRequests !== snapshot.boundedUnresolvedRequests) failure ??= 'request_accounting_unbounded';
+    const receiptHashes = {};
+    try {
+      for (const request of snapshot.requests) receiptHashes[request.requestId] = sha256(await readRegularFile(join(root, 'receipts', `${request.requestId}.json`), limitFor(`receipts/${request.requestId}.json`)));
+    } catch { failure ??= 'request_receipt_missing'; }
+    let ledgerSha256;
+    try { ledgerSha256 = sha256(await readRegularFile(ledgerPath, limitFor('ledger.jsonl'))); }
+    catch { failure ??= 'ledger_evidence_invalid'; }
+    if (observability) {
+      try {
+        observabilityEvidence = await observability.finish({ artifact, cleanupVerified, failure });
+        if (observabilityEvidence.status !== 'accepted') failure ??= 'observability_export_incomplete';
+      } catch { failure ??= 'observability_evidence_incomplete'; }
+    }
+    if (signal?.aborted) failure = 'controller_cancelled';
+    const report = { schema: 'paperclip.runner-eval.control-result/v1', campaignId: manifest.campaignId, manifestSha256,
+      executionId: attempt.executionId, attemptId: attempt.attemptId, requestSha256: attempt.requestSha256,
+      allocationUsd: attempt.maxUsd, limits, startedAt, finishedAt: new Date().toISOString(), status: failure ? 'incomplete' : 'closed', failure,
+      child: child ? { code: child.code, signal: child.signal, stopped: child.stopped } : null,
+      ...(manifest.observability ? { observability: observabilityEvidence ?? { status: 'incomplete', verification: 'unverified' } } : {}),
+      cleanupVerified, secretExcluded, providerArtifactSha256, ledgerSha256, receiptHashes, accounting: snapshot };
+    await atomicJson(join(root, 'result.json'), report);
+    const resultArtifact = controlledResultArtifact(artifact, report, attempt);
+    await mkdir(dirname(resolve(outputPath)), { recursive: true, mode: 0o700 });
+    await writeFile(outputPath, JSON.stringify(resultArtifact, null, 2) + '\n', { flag: 'wx', mode: 0o600 });
+    return { code: failure ? 2 : child?.code ?? 2, report };
+  } finally { try { await observability?.close(); } catch {} }
+
 }
 
 if (process.argv[1] && import.meta.url === pathToFileURL(resolve(process.argv[1])).href) {
diff --git a/packages/paperclip-runner/scripts/controlled-evals/shared-cost-runtime.ts b/packages/paperclip-runner/scripts/controlled-evals/shared-cost-runtime.ts
index b8591390e09..f77c817efd2 100644
--- a/packages/paperclip-runner/scripts/controlled-evals/shared-cost-runtime.ts
+++ b/packages/paperclip-runner/scripts/controlled-evals/shared-cost-runtime.ts
@@ -1,3 +1,9 @@
 export { EvalSpendState, openEvalCostLedger, readEvalCostLedger, parseEvalCostLedger, validEvalLedgerId } from '../../../../tests/runner-e2e/cost-ledger.js';
 export { evalRequestReservation, startEvalGateway } from '../../../../tests/runner-e2e/eval-gateway.js';
 export { EVAL_OVERHEAD_COMPONENTS, validateOperatingOverhead } from '../../../../tests/runner-e2e/operating-overhead.js';
+export { startEvalOtlpRelay, EVAL_OTLP_LIMITS } from '../../../../tests/runner-e2e/eval-otlp-relay.js';
+export { inspectEvalOtlpReceipts } from '../../../../tests/runner-e2e/eval-otlp-receipts.js';
+export { exportBraintrustAttemptParent } from '../../../../tests/runner-e2e/braintrust.js';
+export { reservationBound } from '../../../../tests/runner-e2e/cost-bound-evidence.js';
+export { buildProviderObservabilityLaunch } from '../../../adapter-utils/src/agent-observability.js';
+export { CapabilityMockControlPlaneAdapter } from '../../src/mock-core/capability-mock-control-plane-adapter.js';
diff --git a/tests/runner-e2e/eval-otlp-payload.ts b/tests/runner-e2e/eval-otlp-payload.ts
index 345734f73ec..6ad9cf7c1c0 100644
--- a/tests/runner-e2e/eval-otlp-payload.ts
+++ b/tests/runner-e2e/eval-otlp-payload.ts
@@ -3,7 +3,8 @@ import { evalOtlpSchema as root, protobuf } from "./eval-otlp-schema.js";
 export type EvalOtlpSignal = "traces" | "logs";
 export const isEvalProjectId = (value: string) => /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(value);
 
-export function validateEvalOtlpParent(value: string, projectId: string): string {
+export function validateEvalOtlpParent(value: string, projectId: string, expectedParent?: string): string {
+  if (expectedParent !== undefined && value !== expectedParent) throw new Error("unexpected_otlp_parent");
   if (!isEvalProjectId(projectId)) throw new Error("invalid_otlp_project");
   if (value === `project_id:${projectId}`) return value;
   if (value.length > 2048 || !/^[A-Za-z0-9+/]+={0,2}$/.test(value)) throw new Error("invalid_otlp_parent");
@@ -47,7 +48,7 @@ function validateWire(body: Buffer, type: import("../../server/node_modules/prot
   inspect(type, body.length, 0);
 }
 
-export function validateEvalOtlpPayload(body: Buffer, contentType: string, signal: EvalOtlpSignal, projectId: string) {
+export function validateEvalOtlpPayload(body: Buffer, contentType: string, signal: EvalOtlpSignal, projectId: string, expectedParent?: string) {
   const type = root.lookupType(signal === "traces" ? "TracesData" : "LogsData");
   if (contentType !== "application/json") validateWire(body, type);
   const decoded: unknown = contentType === "application/json" ? JSON.parse(body.toString("utf8")) : type.decode(body).toJSON();
@@ -63,11 +64,11 @@ export function validateEvalOtlpPayload(body: Buffer, contentType: string, signa
       if (!parent || Object.keys(parent).length !== 1) throw new Error("invalid_otlp_parent");
       const text = parent.stringValue ?? parent.string_value;
       if (typeof text !== "string") throw new Error("invalid_otlp_parent");
-      validateEvalOtlpParent(text, projectId);
+      validateEvalOtlpParent(text, projectId, expectedParent);
     }
     if (Object.hasOwn(row, "braintrust.parent")) {
       if (typeof row["braintrust.parent"] !== "string") throw new Error("invalid_otlp_parent");
-      validateEvalOtlpParent(row["braintrust.parent"], projectId);
+      validateEvalOtlpParent(row["braintrust.parent"], projectId, expectedParent);
     }
     Object.values(row).forEach(item => inspect(item, depth + 1));
   };
diff --git a/tests/runner-e2e/eval-otlp-receipts.ts b/tests/runner-e2e/eval-otlp-receipts.ts
new file mode 100644
index 00000000000..ed3fd83b16f
--- /dev/null
+++ b/tests/runner-e2e/eval-otlp-receipts.ts
@@ -0,0 +1,66 @@
+import { EVAL_OTLP_LIMITS } from "./eval-otlp-relay.js";
+
+export interface EvalOtlpReceiptPolicy {
+  projectId: string; campaignId: string; attemptId: string; deadlineAt: string; expectedParent: string;
+  limits: { [K in keyof typeof EVAL_OTLP_LIMITS]: number };
+}
+const equal = (a: unknown, b: unknown) => JSON.stringify(a, (_key, value) => value && typeof value === "object" && !Array.isArray(value)
+  ? Object.fromEntries(Object.entries(value).sort(([a], [b]) => a.localeCompare(b))) : value)
+  === JSON.stringify(b, (_key, value) => value && typeof value === "object" && !Array.isArray(value)
+    ? Object.fromEntries(Object.entries(value).sort(([a], [b]) => a.localeCompare(b))) : value);
+const integer = (value: unknown): value is number => Number.isSafeInteger(value) && Number(value) >= 0;
+
+export function inspectEvalOtlpReceipts(bytes: Buffer, expected: EvalOtlpReceiptPolicy) {
+  if (bytes.length > 2_097_152 || !bytes.length || bytes[bytes.length - 1] !== 10) throw new Error("Incomplete OTLP receipts");
+  const rows = bytes.toString("utf8").trimEnd().split("\n").map(line => {
+    if (Buffer.byteLength(line) > 8192) throw new Error("Oversized OTLP receipt");
+    const row = JSON.parse(line);
+    if (!row || typeof row !== "object" || Array.isArray(row)) throw new Error("Invalid OTLP receipt");
+    return row;
+  });
+  const policy = rows.shift(), closed = rows.pop();
+  const opened = Date.parse(policy?.openedAt), deadline = Date.parse(expected.deadlineAt);
+  if (!equal(policy, { type: "policy", version: 2, sizing: "otlp-v1.9-expanded-source-json", ...expected, openedAt: policy?.openedAt })
+      || !Number.isFinite(opened) || !Number.isFinite(deadline) || opened >= deadline
+      || closed?.type !== "closed" || !Number.isFinite(Date.parse(closed.at)) || Date.parse(closed.at) < opened) throw new Error("OTLP receipt policy or closure mismatch");
+  const usage = { admittedRequests: 0, admittedWireBytes: 0, admittedBytes: 0, admittedExpandedBytes: 0,
+    admittedRecords: 0, attemptedForwardBytes: 0, acceptedRequests: 0, incompleteRequests: 0 };
+  const signals = { logs: { requests: 0, records: 0 }, traces: { requests: 0, records: 0 } };
+  const requests = new Map<string, { bodyBytes: number; recordCount: number; signal: keyof typeof signals; finished: boolean }>();
+  let quotaExhausted = false, pending = 0;
+  for (const row of rows) {
+    const at = Date.parse(row.at);
+    if (!Number.isFinite(at) || at < opened || at > Date.parse(closed.at)) throw new Error("Invalid OTLP receipt time");
+    if (row.type === "quota_exhausted") {
+      if (quotaExhausted || Object.keys(usage).some(key => !integer(row[key]) || row[key] > closed[key])) throw new Error("Invalid OTLP quota receipt");
+      quotaExhausted = true;
+    } else if (row.type === "admitted") {
+      if (at >= deadline || !/^[a-f0-9]{8}(?:-[a-f0-9]{4}){3}-[a-f0-9]{12}$/.test(row.id) || requests.has(row.id)
+          || !["logs", "traces"].includes(row.signal) || !/^[a-f0-9]{64}$/.test(row.payloadSha256)
+          || ![row.wireBytes, row.bodyBytes, row.expandedBytes, row.recordCount].every(integer)
+          || row.wireBytes > expected.limits.maxRequestBytes || row.bodyBytes > expected.limits.maxRequestBytes
+          || ++pending > expected.limits.maxConcurrent) throw new Error("Invalid OTLP admission receipt");
+      requests.set(row.id, { bodyBytes: row.bodyBytes, recordCount: row.recordCount, signal: row.signal, finished: false });
+      usage.admittedRequests++; usage.admittedWireBytes += row.wireBytes; usage.admittedBytes += row.bodyBytes;
+      usage.admittedExpandedBytes += row.expandedBytes; usage.admittedRecords += row.recordCount;
+      if (usage.admittedRequests > expected.limits.maxRequests || usage.admittedBytes > expected.limits.maxTotalBytes
+          || usage.admittedExpandedBytes > expected.limits.maxExpandedBytes || usage.admittedRecords > expected.limits.maxRecords) throw new Error("OTLP receipts exceed allocation");
+    } else if (row.type === "outcome") {
+      const request = requests.get(row.id);
+      if (!request || request.finished || !["accepted", "partial", "rejected", "uncertain", "not_dispatched"].includes(row.outcome)
+          || typeof row.dispatched !== "boolean" || (row.outcome === "not_dispatched") !== !row.dispatched
+          || row.httpStatus !== undefined && (!integer(row.httpStatus) || row.httpStatus < 100 || row.httpStatus > 599)
+          || row.rejectedRecords !== undefined && !integer(row.rejectedRecords)
+          || ["accepted", "partial"].includes(row.outcome) && (!integer(row.rejectedRecords) || row.httpStatus < 200 || row.httpStatus >= 300 || row.httpStatus === undefined
+            || (row.outcome === "accepted") !== (row.rejectedRecords === 0))) throw new Error("Invalid OTLP outcome receipt");
+      request.finished = true; pending--;
+      if (row.dispatched) usage.attemptedForwardBytes += request.bodyBytes;
+      if (row.outcome === "accepted") {
+        usage.acceptedRequests++; signals[request.signal].requests++; signals[request.signal].records += request.recordCount;
+      } else usage.incompleteRequests++;
+    } else throw new Error("Unknown OTLP receipt");
+  }
+  if (pending || closed.poisoned !== false || Object.entries(usage).some(([key, value]) => closed[key] !== value)) throw new Error("Unfinished or inconsistent OTLP receipts");
+  return { ...usage, signals, quotaExhausted, status: quotaExhausted || usage.incompleteRequests ? "incomplete" : usage.admittedRecords ? "accepted" : "empty",
+    verification: "unverified" as const };
+}
diff --git a/tests/runner-e2e/eval-otlp-relay.test.ts b/tests/runner-e2e/eval-otlp-relay.test.ts
index 7b220dc0f45..55f15eebe23 100644
--- a/tests/runner-e2e/eval-otlp-relay.test.ts
+++ b/tests/runner-e2e/eval-otlp-relay.test.ts
@@ -273,3 +273,20 @@ it("rejects unknown protobuf fields instead of excluding forwarded data from siz
   expect(response.status).toBe(400);
   expect(upstream).not.toHaveBeenCalled();
 });
+
+it("binds native relay headers and payload parents to the assigned attempt within the same project", async () => {
+  const expectedParent = exportBraintrustAttemptParent({ projectId, spanId: "1234567890abcdef", traceId: "abcdef0123456789abcdef0123456789" });
+  const other = exportBraintrustAttemptParent({ projectId, spanId: "abcdef0123456789", traceId: "abcdef0123456789abcdef0123456789" });
+  const upstream = vi.fn<typeof fetch>(async () => Response.json({}));
+  const f = await fixture({ expectedParent, transport: upstream });
+  expect((await f.send()).status).toBe(400);
+  expect((await f.send("{}", { "x-bt-parent": other })).status).toBe(400);
+  for (const parent of [other, `project_id:${projectId}`]) {
+    const body = { resourceLogs: [{ resource: { attributes: [{ key: "braintrust.parent", value: { stringValue: parent } }] } }] };
+    expect((await f.send(JSON.stringify(body), { "x-bt-parent": expectedParent }, "/v1/logs")).status).toBe(400);
+  }
+  expect(upstream).not.toHaveBeenCalled();
+  expect((await f.send("{}", { "x-bt-parent": expectedParent })).status).toBe(200);
+  await f.relay.close();
+  expect((await f.records())[0].expectedParent).toBe(expectedParent);
+});
diff --git a/tests/runner-e2e/eval-otlp-relay.ts b/tests/runner-e2e/eval-otlp-relay.ts
index d34efd814e5..bb71078e283 100644
--- a/tests/runner-e2e/eval-otlp-relay.ts
+++ b/tests/runner-e2e/eval-otlp-relay.ts
@@ -14,7 +14,7 @@ export const EVAL_OTLP_DEFAULT_LIMITS = { ...EVAL_OTLP_LIMITS,
 
 export async function startEvalOtlpRelay(input: {
   projectId: string; apiKey: string; campaignId: string; attemptId: string; receiptPath: string; deadlineAt: number;
-  limits?: { [K in keyof typeof EVAL_OTLP_LIMITS]: number }; transport?: typeof fetch;
+  limits?: { [K in keyof typeof EVAL_OTLP_LIMITS]: number }; transport?: typeof fetch; expectedParent?: string;
 }) {
   const limits = input.limits ?? EVAL_OTLP_DEFAULT_LIMITS;
   if (!isEvalProjectId(input.projectId) || !input.apiKey.trim() || /[\r\n]/.test(input.apiKey)
@@ -24,6 +24,7 @@ export async function startEvalOtlpRelay(input: {
     || Object.keys(limits).sort().join(",") !== Object.keys(EVAL_OTLP_LIMITS).sort().join(",")
     || Object.entries(EVAL_OTLP_LIMITS).some(([key, maximum]) => !Number.isSafeInteger(limits[key as keyof typeof limits])
       || limits[key as keyof typeof limits] < 1 || limits[key as keyof typeof limits] > maximum)) throw new Error("Invalid eval OTLP relay policy");
+  if (input.expectedParent !== undefined) validateEvalOtlpParent(input.expectedParent, input.projectId);
   await mkdir(path.dirname(input.receiptPath), { recursive: true, mode: 0o700 });
   const file = await open(input.receiptPath, "ax", 0o600);
   let writes = Promise.resolve(), poisoned = false, closed = false, quotaRecorded = false;
@@ -33,7 +34,7 @@ export async function startEvalOtlpRelay(input: {
     return writes;
   };
   try { await record({ type: "policy", version: 2, sizing: "otlp-v1.9-expanded-source-json", projectId: input.projectId, campaignId: input.campaignId,
-    attemptId: input.attemptId, limits, deadlineAt: new Date(input.deadlineAt).toISOString(), openedAt: new Date().toISOString() }); }
+    attemptId: input.attemptId, ...(input.expectedParent === undefined ? {} : { expectedParent: input.expectedParent }), limits, deadlineAt: new Date(input.deadlineAt).toISOString(), openedAt: new Date().toISOString() }); }
   catch (error) { await file.close(); throw error; }
   const token = randomBytes(32).toString("hex");
   const pending = new Set<Promise<void>>(), controllers = new Set<AbortController>();
@@ -57,7 +58,7 @@ export async function startEvalOtlpRelay(input: {
       if (!["application/json", "application/x-protobuf"].includes(contentType ?? "") || encoding && encoding !== "gzip" && encoding !== "identity") return deny(response, 415, "unqualified_encoding");
       let body: Buffer, parent: string, wireBytes = 0, expandedBytes = 0, recordCount = 0;
       try {
-        parent = validateEvalOtlpParent(String(request.headers["x-bt-parent"] ?? `project_id:${input.projectId}`), input.projectId);
+        parent = validateEvalOtlpParent(String(request.headers["x-bt-parent"] ?? `project_id:${input.projectId}`), input.projectId, input.expectedParent);
         const chunks: Buffer[] = [];
         for await (const chunk of request) {
           wireBytes += chunk.length;
@@ -66,7 +67,7 @@ export async function startEvalOtlpRelay(input: {
         }
         body = Buffer.concat(chunks);
         if (encoding === "gzip") body = gunzipSync(body, { maxOutputLength: limits.maxRequestBytes });
-        const validated = validateEvalOtlpPayload(body, contentType!, signal, input.projectId);
+        const validated = validateEvalOtlpPayload(body, contentType!, signal, input.projectId, input.expectedParent);
         ({ body, expandedBytes, recordCount } = validated);
         if (body.length > limits.maxRequestBytes) throw new Error("request_limit");
       } catch { return deny(response, 400, "invalid_or_oversized_payload"); }