fix(harness): preserve failed Claude result diagnostics (#797)

BUILD-LOG.md

@@ -6202,3 +6202,12 @@ Before: isolated branch fix/mvp3-coder-stall-797 starts at 05fdfef9ea1fdddf58c72
 After: Claude's private stream-json reader marks real upstream assistant events and emits only the successful final text, matching real CLI newline semantics byte for byte. Pi's existing extension also marks model text/thinking/tool deltas; mock remains a test-only immediate echo. Both reuse the existing exclusive 0600 proxy-first-output marker with fixed output\n content; init/status, synthetic CLI errors, tool results, stderr and workspace writes do not count. Runner supplies only its existing run directory; helper gets a read-only harness mount and bundle source digest. No timeout, schema, role authority, credential, proxy management or live state changed. Silent runs still stop with proxy-stall; interrupted first/resumed turns emit no partial answer or successful new session ID.
 
 Verification: Node v24.22.1 with PATH pinned to /mnt/storage/scratch/tmp/z62zsJ/node24/node_modules/node-linux-x64/bin and fresh TMPDIR from mktemp -d /mnt/storage/scratch/tmp/XXXXXX. Final full 28-file command: 376 passed, 0 failed/cancelled/skipped/todo, test-concurrency=4 (coder-stall-final-r2.tap). Includes full launcher/model-stall, harness runner/bundle, seat session/sandbox, real Claude/Pi adapter, confinement, installer/copy, source-digest and import-closure checks. Delayed tool/thinking/header/assistant fixtures use 0.8-second injected watchdog and 1.4-second pre-answer work. Initial tests retained: missing test import and failed-result exit handling, real text-mode trailing-newline difference, then a combined-gate grandchild-reaping assertion race; all corrected and full final gate green. Whitespace and baseline log-prefix preservation checks pass. Report, exact commands, SHA256 manifest, scans and all TAP receipts: /mnt/storage/scratch/mosaic-lead/mvp3/coder-stall-fix-r1-report.md and coder-stall-* siblings. Local commit follows these green suites. Independent exact-commit review, CI/integration and deployment/live GLM acceptance remain with the lead; no push, stash, fleet operation or external message.
+
+
+## 2026-11-05 — MVP 3 coder-stall review F1 correction (#797), local implementation handoff
+
+Before: candidate 1bd0077391f1925db5e66796b98540e48f13bfc2 discarded complete error-typed result strings, losing text-mode stdout such as API Error: 400 review-local-api-error with exit 1. Restoring that output also required preventing the runner's generic stdout fallback from mistaking synthetic errors for model activity. Explicit correction charter authorizes one local follow-up commit on fix/mvp3-coder-stall-797; the linked-worktree queue refusal was diagnosed and left intact.
+
+After: the private stream reader renders every complete final result string independently of success/failure, retains CLI nonzero exit codes, fails error-typed zero-exit turns, and withholds result text on stream-integrity/helper marker failures. The adapter's existing success-only session persistence remains unchanged. The Claude plugin declares adapter-owned activity in its existing bundle environment; the runner reads module metadata, ignores ambient declarations and keeps stdout fallback for Pi/worker/mock paths. No core harness-name conditional, watchdog timing/default, broker, roles, contracts, policy or live state change. Bundle tests pin the helper SHA-256 to 9c2cc28b7e719c1d49913401fffc952759d8633e50ae39ca36bfc50729b9415b.
+
+Verification: before product edits, whole-file negative controls on 1bd007739 passed 68 and failed 7; the real installed Claude CLI HTTP 400 test failed on empty streaming stdout versus 38 text-mode bytes. It now passes with identical stdout bytes and exit 1, no activity marker and no new session ID, using only localhost, isolated HOME/configuration and a dummy key. Added subtype/is_error/nonzero controls, corrupt-after-result/oversized/truncated/helper marker-failure cases and real runner fallback controls. Final frozen gate: 414 passed, 0 failed/skipped/cancelled/todo across 31 whole files, one node --test invocation per file, at most two concurrently. Node v24.22.1 on the requested PATH; set -o pipefail and fresh scratch TMPDIR. The initial broad gate's sole architecture failure (412/413) is retained honestly; moved the declaration into the plugin and reran all 31 files green. Whitespace, source hashes and append-only prefix checks pass. Report: /mnt/storage/scratch/mosaic-lead/mvp3/coder-stall-fix-r2-report.md; per-file TAPs, exact commands, negative controls, source/pin scans and hashes: coder-stall-fix-r2-evidence/. Local commit follows verification; independent exact-commit review remains with the lead. No push, stash, forge write, real model call, contact with 10.1.1.53, deployment or live recovery.

adapters/README.md

@@ -77,6 +77,7 @@ session's workspace and its own process group. Same contract, plus:
 | `MOSAIC_TOOL_SOCKET` | The runner's tool socket, which the typed tools call. |
 | `MOSAIC_TURN_MARKER` | `pi`: the extension writes it at `agent_end`; a pi turn that exits 0 without it failed. |
 | `MOSAIC_MODEL_ACTIVITY_DIR` | Managed runner's existing writable run directory. Trusted model streaming events publish the fixed `output\n` token to `proxy-first-output` (0600, exclusive create). No event contents or credentials enter it. Claude's private stream reader and Pi's extension signal thinking, tool-use and text activity before final stdout; init/status, tool results and workspace writes do not count. |
+| `MOSAIC_MODEL_ACTIVITY_SOURCE` | The harness module may set `adapter` in its bundle environment to declare model events authoritative and disable the runner's stdout activity fallback. Claude declares this because final stdout can be a synthetic error. Pi and mock retain the fallback. The runner reads the declaration from module metadata, ignoring any ambient environment copy. |
 | `MOSAIC_EXTENSIONS` | `pi` only: extension files loaded with `-e`; a missing one exits 2. The pi module names two: the gate and typed tools extension, then the unslop check's `tools/unslop-hook/extension.ts` (row 66). |
 | `MOSAIC_UNSLOP_LOG` | The unslop check's JSONL log, `<run>/unslop.jsonl`, which the runner sets for both adapters and reads after each turn (row 66). |
 | `MOSAIC_CLAUDE_SETTINGS`, `MOSAIC_CLAUDE_MCP_CONFIG` | `claude` only: the bundle's gate hook and MCP server; required. |
@@ -87,9 +88,12 @@ The layers each adapter relies on, and what they don't cover, are in
 `packages/harness/README.md`.
 
 Claude uses `--output-format stream-json --verbose --include-partial-messages`.
-The adapter's `stream.mjs` consumes those events and prints only the successful
-final result, with the same newline as the CLI's text format. Malformed or
-incomplete streams fail the turn; a failed or interrupted first turn still
+The adapter's `stream.mjs` consumes those events and prints a complete final
+result, including error results, with the same newline as the CLI's text format.
+CLI failures retain their nonzero exit status. Claude's model events alone mark
+activity; its final stdout may be a synthetic error. The runner retains stdout
+activity marking for Pi and mock adapters. Malformed or incomplete streams emit
+only the fixed diagnostic and fail the turn; a failed or interrupted first turn
 does not persist a reusable session ID. The helper is mounted read-only and
 its digest is recorded in the launch bundle. Pi retains print mode and signals
 activity through its existing extension. Mock remains a test-only echo.

adapters/claude/stream.mjs

@@ -1,5 +1,5 @@
-// Consume Claude Code's SDK event stream privately. Only the successful result
-// reaches stdout, ensuring a trailing newline like --output-format text.
+// Consume Claude Code's SDK event stream privately. A complete final result
+// reaches stdout, including errors, with the same newline as text mode.
 import { spawn } from 'node:child_process';
 import { firstOutputMarker } from '../../packages/harness/src/first-output.mjs';
 
@@ -37,10 +37,8 @@ function event(line) {
     resultSeen = true;
     // Let a normal CLI failure exit on its own, retaining its exit code.
     resultFailed = item.subtype !== 'success' || !!item.is_error;
-    if (!resultFailed) {
-      if (typeof item.result !== 'string') throw Error();
-      answer = item.result;
-    }
+    if (typeof item.result === 'string') answer = item.result;
+    else if (!resultFailed) throw Error();
   }
 }
 child.stdout.setEncoding('utf8');
@@ -63,10 +61,11 @@ child.on('close', (code, signal) => {
   if (!failed && pending) {
     try { event(pending); } catch { fail(); }
   }
-  if (failed || resultFailed || code !== 0 || signal || answer === undefined) {
-    if (!failed && code === 0 && !signal) fail();
-    process.exitCode = code || 2;
-  } else {
+  // Integrity and rendering are separate from the CLI's success classification.
+  // Buffer until close so corrupt/truncated streams never leak a final result.
+  if (!failed && (!resultSeen || signal)) fail();
+  if (!failed && answer !== undefined) {
     process.stdout.write(answer.endsWith('\n') ? answer : answer + '\n');
   }
+  process.exitCode = code || (failed || resultFailed ? 2 : 0);
 });

docs/SESSIONS.md

@@ -2066,3 +2066,4 @@ are never rewritten or removed; corrections are new entries.
 2026-11-04 | Mos, skill integrator | #818 / Gitea #1845 | Integrated exact independently approved ms-ux-improvement candidate02 into source;3hashes/validator/whitespace pass and author histories preserved. Separate commit from MVP; its activation target staysbd8120318. No install, activation, publication or live action.
 
 2026-11-05 | Codex implementation child | MVP 3 #797 D2 coder-stall fix on fix/mvp3-coder-stall-797 from 05fdfef9e | Claude private streaming activity marker + answer-only stdout; Pi model-event coverage; silent/interrupted controls preserved. Final Node 24.22.1 full 28-file gate: 376 pass, 0 fail/skip/cancel. Queue refused linked worktree; no workaround. Local commit only, no push/stash/live actions. Report: /mnt/storage/scratch/mosaic-lead/mvp3/coder-stall-fix-r1-report.md; independent review remains with lead.
+2026-11-05 | Implementation child | MVP 3 #797 coder-stall review F1 on fix/mvp3-coder-stall-797 from 1bd007739 | Preserve complete failed Claude result stdout and exit status; module-declared model activity disables synthetic stdout marking while Pi/worker/mock fallback remains. Real localhost HTTP 400 regression fails baseline and passes fix; final Node 24.22.1 gate 414/414 across 31 whole files, no skips. One local commit only; no push/stash/forge/live actions. Queue refused linked worktree without workaround. Report: /mnt/storage/scratch/mosaic-lead/mvp3/coder-stall-fix-r2-report.md; independent review remains with lead.

packages/harness/src/runner.mjs

@@ -345,7 +345,12 @@ function runTurn({ session, request, n, env, onChild }) {
   closeSync(errFd);
   onChild(child);
   let out = "";
-  const markOutput = firstOutputMarker(session.runDir);
+  // The harness module may declare its adapter's model events authoritative.
+  // Such adapters can print synthetic error results, which aren't activity.
+  // Read the declaration from module metadata, never the ambient environment;
+  // adapters without it retain the stdout fallback (including worker paths).
+  const markOutput = session.harnessEnv.MOSAIC_MODEL_ACTIVITY_SOURCE === 'adapter'
+    ? () => {} : firstOutputMarker(session.runDir);
   child.stdout.setEncoding("utf8");
   child.stdout.on("data", (s) => {
     markOutput(s);

packages/harness/tests/bundle.test.mjs

@@ -152,6 +152,7 @@ test("a claude-code bundle adds the wrapped gate hook and the MCP config", (t) =
   assert.ok(m.typed.every((n) => n.startsWith("mcp__mosaic__")));
   assert.equal(m.sources.claudeStream.path, join(REPO, "adapters/claude/stream.mjs"));
   assert.equal(m.sources.claudeStream.sha256, sha(m.sources.claudeStream.path));
+  assert.equal(m.sources.claudeStream.sha256, "9c2cc28b7e719c1d49913401fffc952759d8633e50ae39ca36bfc50729b9415b");
   assert.deepEqual(Object.keys(m.sources).sort(), ["claudeGate", "claudeStream", "gate", "mcpServer", "tools", "unslopCheck", "unslopHook", "unslopLists"]);
   // Row 66 (#1559): the unslop hooks run after a reply and before the next prompt, and never block.
   for (const [event, which] of [["Stop", "stop"], ["UserPromptSubmit", "prompt"]]) {

packages/harness/tests/claude-session.test.mjs

@@ -6,6 +6,7 @@ import { fixtureCacheEnv } from '../../../scripts/testing/lane-fixtures.mjs';
 // except the argv check, which uses a stand-in claude.
 
 import { test } from "node:test";
+import { createServer as createHttp } from "node:http";
 import assert from "node:assert/strict";
 import { spawn, spawnSync } from "node:child_process";
 import { chmodSync, existsSync, mkdirSync, readFileSync, realpathSync, rmSync, symlinkSync, writeFileSync } from "node:fs";
@@ -66,14 +67,15 @@ async function session(t, script, tools = ["read", "bash"], done = (r) => `ANSWE
 function turn(env, request, cwd, adapter = ADAPTER) {
   return new Promise((resolve) => {
     const child = spawn("/bin/sh", [adapter], { cwd, env: { ...env, ...fixtureCacheEnv(env.CLAUDE_CONFIG_DIR), MOSAIC_REQUEST: request }, stdio: ["ignore", "pipe", "pipe"], detached: true });
-    let stdout = "";
+    const chunks = [];
     let stderr = "";
-    child.stdout.on("data", (b) => (stdout += b));
+    child.stdout.on("data", (b) => chunks.push(b));
     child.stderr.on("data", (b) => (stderr += b));
     const clock = setTimeout(() => process.kill(-child.pid, "SIGKILL"), 120_000);
     child.on("close", (code) => {
       clearTimeout(clock);
-      resolve({ code, stdout, stderr });
+      const stdoutBytes = Buffer.concat(chunks);
+      resolve({ code, stdout: stdoutBytes.toString("utf8"), stdoutBytes, stderr });
     });
   });
 }
@@ -158,6 +160,48 @@ test(`claude: streaming preserves the real CLI text answer byte for byte (${JSON
 });
 }
 
+test("claude: HTTP 400 keeps real text-mode stdout and exit status without model activity or a new session", { skip }, async t => {
+  const { dir, workspace, env } = await session(t, [], []);
+  let requests = 0;
+  const api = createHttp((req, res) => {
+    req.resume();
+    req.on('end', () => {
+      if (!/\/messages(\?|$)/.test(req.url)) {
+        res.writeHead(200, { 'content-type': 'application/json' });
+        return res.end(JSON.stringify({ input_tokens: 1 }));
+      }
+      requests++;
+      res.writeHead(400, { 'content-type': 'application/json' });
+      res.end(JSON.stringify({ type: 'error', error: { type: 'invalid_request_error', message: 'review-local-api-error' } }));
+    });
+  });
+  await new Promise(resolve => api.listen(0, '127.0.0.1', resolve));
+  t.after(() => api.close());
+  const textAdapter = join(dir, 'text-adapter.sh');
+  writeFileSync(textAdapter, readFileSync(ADAPTER, 'utf8')
+    .replace('node "$STREAM" "$CLAUDE"', '"$CLAUDE"')
+    .replace('--output-format stream-json --verbose --include-partial-messages', '--output-format text'));
+  const results = [];
+  for (const [name, adapter] of [['text', textAdapter], ['stream', ADAPTER]]) {
+    const runDir = join(dir, name);
+    mkdirSync(runDir);
+    const result = await turn({ ...env,
+      HOME: join(runDir, 'home'), CLAUDE_CONFIG_DIR: join(runDir, 'config'),
+      ANTHROPIC_BASE_URL: `http://127.0.0.1:${api.address().port}`,
+      MOSAIC_SESSION_DIR: join(runDir, 'session'), MOSAIC_MODEL_ACTIVITY_DIR: runDir,
+    }, 'answer', workspace, adapter);
+    results.push(result);
+    assert.equal(result.code, 1, `${name}: ${result.stderr}`);
+    assert.equal(existsSync(join(runDir, 'session/claude-session-id')), false, name);
+    assert.equal(existsSync(join(runDir, 'proxy-first-output')), false, name);
+  }
+  const [text, stream] = results;
+  assert.ok(requests >= 2, 'both real CLI invocations reached only the local scripted API');
+  assert.deepEqual(text.stdoutBytes, Buffer.from('API Error: 400 review-local-api-error\n'));
+  assert.deepEqual(stream.stdoutBytes, text.stdoutBytes);
+  assert.equal(stream.code, text.code);
+});
+
 // --restricted is what keeps CLAUDE.md files and auto-memory out of the
 // session's prompt (README "Limits"). This one runs without claude: a
 // stand-in records the adapter's argv.

packages/harness/tests/fixtures/claude-activity.mjs

@@ -2,8 +2,9 @@
 import { writeFileSync } from 'node:fs';
 import { join } from 'node:path';
 const args = process.argv.slice(2);
-const answer = '  Answer é 🦆\nsecond line\n';
 const mode = process.env.FAKE_CLAUDE_MODE ?? 'tool';
+const answer = mode === 'failed' || mode === 'failed-success-subtype' || mode === 'failed-zero-exit'
+  ? 'API Error: 400 fixture-error' : '  Answer é 🦆\nsecond line\n';
 writeFileSync(join(process.env.MOSAIC_WORKSPACE, 'cli-pid'), String(process.pid));
 const emit = item => process.stdout.write(JSON.stringify(item) + '\n');
 if (args[args.indexOf('--output-format') + 1] === 'text') {
@@ -20,9 +21,15 @@ if (args[args.indexOf('--output-format') + 1] === 'text') {
     process.stdout.write('invalid credential-canary\n');
   } else if (mode === 'missing') {
     // Exit 0 without a result still fails the adapter.
-  } else if (mode === 'failed') {
-    emit({ type: 'result', subtype: 'error_during_execution', is_error: true, errors: ['credential-canary'] });
-    process.exitCode = 7;
+  } else if (['failed', 'failed-success-subtype', 'failed-zero-exit', 'nonzero-success'].includes(mode)) {
+    emit({ type: 'result', subtype: mode === 'failed-success-subtype' || mode === 'nonzero-success' ? 'success' : 'error_during_execution',
+      is_error: mode === 'failed-success-subtype', result: answer, errors: ['credential-canary'] });
+    process.exitCode = mode === 'failed-zero-exit' ? 0 : 7;
+  } else if (['malformed-after-result', 'oversized', 'truncated'].includes(mode)) {
+    // A complete answer before corrupt trailing data must still be withheld.
+    emit({ type: 'result', subtype: 'success', result: answer });
+    process.stdout.write(mode === 'oversized' ? 'x'.repeat(16 * 1024 * 1024 + 1)
+      : mode === 'truncated' ? '{"type":"result"' : 'invalid credential-canary\n');
   } else {
     if (mode !== 'silent') {
       const event = mode === 'thinking'

packages/harness/tests/model-activity.test.mjs

@@ -118,17 +118,42 @@ test(`interrupted Claude activity emits no partial answer, preserves session sta
 });
 }
 
-for (const mode of ['malformed', 'missing', 'failed']) {
+for (const mode of ['malformed', 'missing', 'malformed-after-result', 'oversized', 'truncated']) {
   test(`Claude ${mode} stream fails closed without raw event diagnostics or a session receipt`, async t => {
     const f = fixture(t, mode), result = await start(t, f).done;
     assert.notEqual(result.code, 0);
-    if (mode === 'failed') assert.equal(result.code, 7, 'preserve the CLI exit code');
     assert.equal(result.stdout.length, 0);
+    assert.match(result.stderr, /claude adapter: invalid or incomplete model stream/);
     assert.doesNotMatch(result.stderr, /credential-canary/);
     assert.equal(existsSync(join(f.runDir, 'session/claude-session-id')), false);
   });
 }
 
+test('Claude helper marker failure keeps the fixed diagnostic and emits no result', async t => {
+  const f = fixture(t);
+  // A file where the marker directory should be makes the private helper fail.
+  f.env.MOSAIC_MODEL_ACTIVITY_DIR = join(f.runDir, 'prompt');
+  const result = await start(t, f).done;
+  assert.notEqual(result.code, 0);
+  assert.equal(result.stdout.length, 0);
+  assert.match(result.stderr, /claude adapter: invalid or incomplete model stream/);
+  assert.doesNotMatch(result.stderr, /credential-canary|ENOTDIR/);
+  assert.equal(existsSync(join(f.runDir, 'session/claude-session-id')), false);
+  assert.equal(existsSync(join(f.runDir, 'proxy-first-output')), false);
+});
+
+for (const mode of ['failed', 'failed-success-subtype', 'failed-zero-exit', 'nonzero-success']) {
+  test(`Claude ${mode} renders the final result independently of failure without a session or synthetic activity`, async t => {
+    const f = fixture(t, mode), result = await start(t, f).done;
+    assert.equal(result.code, mode === 'failed-zero-exit' ? 2 : 7);
+    const answer = spawnSync(f.cli, ['--output-format', 'text'], { env: f.env });
+    assert.deepEqual(result.stdout, answer.stdout);
+    assert.doesNotMatch(result.stderr, /invalid or incomplete model stream/);
+    assert.equal(existsSync(join(f.runDir, 'session/claude-session-id')), false);
+    assert.equal(existsSync(join(f.runDir, 'proxy-first-output')), false);
+  });
+}
+
 test('Pi extension marks real streamed thinking/tools/text, never local activity or user/tool messages', async t => {
   const runDir = scratch(t);
   writeFileSync(join(runDir, 'policy'), JSON.stringify({ harness: 'pi', tools: [], typed: [] }));

packages/harness/tests/runner.test.mjs

@@ -228,6 +228,28 @@ test("a message becomes a turn, the answer goes back as a RESULT, SIGTERM releas
   assert.ok(!existsSync(join(ctx.runDir, "tools.sock")));
 });
 
+// Claude's private stream reader owns model activity; final result stdout alone
+// (even a synthetic success) must not cancel the model watchdog. Other adapters
+// still need the stdout fallback when no streaming producer is installed.
+for (const [harness, exit, activity] of [['claude-code', 1, false], ['claude-code', 0, false], ['pi', 0, true], ['mock', 0, true]]) {
+  test(`stdout activity fallback: ${harness}, adapter exit ${exit}`, async t => {
+    const ctx = await setup(t, { session: { harness, turnEnd: 'exit',
+      harnessEnv: activity ? {} : { MOSAIC_MODEL_ACTIVITY_SOURCE: 'adapter' },
+    } });
+    ctx.inbox = [];
+    writeFileSync(join(ctx.dir, 'adapter.sh'), `printf 'API Error: 400 synthetic-result\\n'\nexit ${exit}\n`);
+    // An ambient declaration cannot suppress the fallback for other adapters.
+    const r = startRunner(ctx.runDir, ctx.cap, { MOSAIC_MODEL_ACTIVITY_SOURCE: 'adapter' });
+    t.after(async () => { r.child.kill('SIGTERM'); await r.exited; });
+    const reply = await ask(ctx);
+    if (exit) assert.match(reply.body, /The turn failed: adapter exited 1/);
+    else assert.equal(reply.body, 'API Error: 400 synthetic-result');
+    const marker = join(ctx.runDir, 'proxy-first-output');
+    assert.equal(existsSync(marker), activity);
+    if (activity) assert.equal(readFileSync(marker, 'utf8'), 'output\n');
+  });
+}
+
 // Row 109 (#1603): each turn reads the state when it starts. The fake adapter echoes the request,
 // so a reply shows the block the turn was given.
 const ask = async (ctx, body = "what now") => {

packages/plugins/harness/claude-code/index.mjs

@@ -124,6 +124,8 @@ export function env({ files, policy, session, proxy = null }) {
     MOSAIC_CLAUDE_SETTINGS: files.settings,
     MOSAIC_CLAUDE_MCP_CONFIG: files.mcp,
     MOSAIC_THINKING: session.thinking,
+    // stream.mjs marks upstream model events; final stdout may be an API error.
+    MOSAIC_MODEL_ACTIVITY_SOURCE: "adapter",
     ...(proxy ? { ANTHROPIC_BASE_URL: proxy.baseUrl, ANTHROPIC_AUTH_TOKEN: proxy.key } : {}),
   };
 }

packages/plugins/tests/harness.test.mjs

@@ -111,6 +111,7 @@ test("row 65 env passes the thinking level to both adapters, and claude-code's b
   const session = { provider: "fixture", model: "m", thinking: "high", toolSocket: "/run/tools.sock" };
   const piEnv = pi.env({ policy: { tools: ["read"] }, tools: [{ name: "list_tasks" }], session });
   assert.deepEqual([piEnv.MOSAIC_THINKING, piEnv.PI_MODEL, piEnv.MOSAIC_TOOLS], ["high", "m", "read,list_tasks"]);
+  assert.equal(piEnv.MOSAIC_MODEL_ACTIVITY_SOURCE, undefined, "Pi retains stdout fallback for paths without streaming activity");
   // Row 66: pi loads the unslop check as its second extension.
   assert.deepEqual(piEnv.MOSAIC_EXTENSIONS.split(","), [join(REPO, "packages", "harness", "src", "pi-extension.mjs"), join(REPO, "tools", "unslop-hook", "extension.ts")]);
   const dir = scratch(t);
@@ -127,6 +128,7 @@ test("row 65 env passes the thinking level to both adapters, and claude-code's b
   assert.match(settings.hooks.UserPromptSubmit[0].hooks[0].command, /^timeout -k 2 10 .*claude-hook\.js' prompt; exit 0$/);
   assert.equal(JSON.parse(readFileSync(join(dir, "mcp.json"), "utf8")).mcpServers.mosaic.args.at(-1), "/run/tools.sock");
   const claudeEnv = claude.env({ files: out.files, policy: { tools: ["read"], typed: [] }, session });
+  assert.equal(claudeEnv.MOSAIC_MODEL_ACTIVITY_SOURCE, "adapter");
   assert.deepEqual([claudeEnv.MOSAIC_THINKING, claudeEnv.MOSAIC_CLAUDE_SETTINGS, claudeEnv.MOSAIC_CLAUDE_MCP_CONFIG], ["high", out.files.settings, out.files.mcp]);
 });