Watchdog test fixture, not a mod to install. live probe: a second plugin's spawn against the session-wide subagent cap

A second model reviews each step that Claude Code takes and sends it short notes while it works: nit, concern or blocker.

Claude Code 2.1.290 or later. Watchdog is a mod: a plugin whose code Claude Code runs inside your session. The npm stable channel (2.1.285 on 2026-10-06) has no mods. Below 2.1.290 the plugin shows unsupported. Desktop support starts when Claude.app bundles Claude Code 2.1.290 or later.
Check claude --version first. If it is below 2.1.290, move to the npm latest channel: npm install -g @anthropic-ai/claude-code@latest.
/plugin marketplace add matteoantoci/claude-plugins
/plugin install watchdog@matteoantoci-plugins
Then run /watchdog on (reviews are off until you do) and ask Claude for a small change. The note shows as a watchdog: [concern] … line in the transcript and as a card, one line with its first sentence above the prompt box. Click the card's ▸, or press ctrl+x tab and then its letter (a, b, c), to read the whole note with its watchdog, age and state; Esc gives the focus back to the prompt. Run /watchdog status to see each watchdog's reviews, notes, tokens and cost. A card names its watchdog when you run two or more.
At its right end a card shows only what needs a look: the subagent type for a note on a subagent; the state while the note has not reached Claude yet, nudge pending (the plugin starts a turn so that Claude reads it), held or aside (Claude reads it with your next prompt); nothing once it is steered (Claude reads it after its next tool result) or nudged. When Claude edited files after the review read its update, the card says outdated? N edits (the open card says may be outdated: N edits since), and Claude reads the same mark with the note. The next review of the same watchdog sees the edits and the note; when the note no longer holds, it retracts it: the card goes, and a note that waits never reaches Claude. A blocker that may be outdated and came after Claude's reply waits as held for that review before it nudges, so Claude does not go after a bug it already fixed.
plugins/watchdog/hooks/.WATCHDOG.json and WATCHDOG.md files, the session's memory files (such as CLAUDE.md), each update of the agent you work with and, when CLAUDE_WATCHDOG is set in a claude -p run, your project and local settings./watchdog on also sends one 1-token request for each model, to check that it exists. Apart from these model requests through Claude Code, the mod makes no network calls: its code never calls $.http.fetch or fetch.<config>/watchdog/dumps/ (<config> is $CLAUDE_CONFIG_DIR or ~/.claude). It keeps its notes and review state in Claude Code's session state and plugin store. In the terminal, /watchdog dump also copies the dump text to the clipboard.Read, Grep and Glob. A project WATCHDOG.json can grant no more; only <config>/WATCHDOG.json can grant other tools and mcp__* tools. Bash, Edit, Write, NotebookEdit, Agent, SendMessage, AskUserQuestion and ToolSearch are always refused. A reviewer never asks you for a permission.Agent call of a watchdog:* type) when Claude Code would ask, so no dialog or Auto-mode classifier sees it. A permission rule that denies Agent still wins.WATCHDOG.json or WATCHDOG.md sets the number of reviewers, their model, effort and instructions. In a repo you did not write, read these files before /watchdog on. Once on, /watchdog status lists each watchdog with its model, effort and file.opus with medium effort by default (in the demo: 3 reviews, 37.2k tokens, $0.07). The built-in "You should know" mod, when on, runs its own side agent too; turn it off in /plugin to pay for one only./watchdog off stops reviews for this session. /plugin uninstall watchdog@matteoantoci-plugins removes the plugin./plugin (Installed, Watchdog, Configure options) or /config: onByDefault (default false) turns reviews on in each new interactive session. immuneTurns (0 to 5, default 3) is the number of turns after a nudge before the next nudge for a concern; a nudge is a turn that the plugin starts so that Claude reads a note that came after its reply./watchdog status shows both counts, for example nudge 1/1 · blocker 0/2./watchdog or /watchdog status: each watchdog's state, reviews, notes, tokens and cost, and the session totals. For a state such as halted, see docs/failures.md./watchdog on and /watchdog off: turn reviews on or off for this session./watchdog dump and /watchdog dump raw: write the review log to a file (raw adds the review prompts).A WATCHDOG.json in your project or in ~/.claude sets the watchdogs. The load order, every key and the tool grants are in docs/configuration.md. This file adds a second reviewer to the default one:
{ "watchdogs": [{ "name": "default" }, { "name": "security", "model": "sonnet", "effort": "high" }] }
claude -p needs CLAUDE_WATCHDOG=on and has no nudge and no cards: see docs/headless.md.plugins/watchdog/hooks/prices.ts); a model not in it shows $?.npm install sets up the tools and the pre-commit hook. npm run check runs the 6 checks of pre-commit and CI: rules, fmt:check, lint, typecheck, validate and test. See docs/plugin-dev.md. Before a release and before a bump of the pinned Claude Code version, run the live probe by hand, on a real model and login: scripts/live-probe/README.md.
Apache-2.0
hooks/peer.mjs 78 lines1// §16.5 the caps in the TUI (spec §12.2; research/stop-caps-probe.md P2). With CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS=1
2// and rr-stop's holder in the only session slot, this plugin's own per-plugin count is 0, so the session cap (shared
3// by every plugin and the primary agent) is the one that refuses its spawn. It acts at the main turn.complete of the
4// prompt that carries RRPEER. installMod fills __LOG__ and __HOLD__ (the proxy holds the agent if it ever runs; it is
5// then stopped at once). Result: __LOG__/rr-peer.json.
6const FILE = '__LOG__/rr-peer.json';
7const HOLD = '__HOLD__';
8const PLUGIN = 'rrpeer';
9const MARKER = 'RRPEER';
10
11const state = { phase: 'idle' };
12let lastText = '';
13
14const errOf = (err) => ({ name: err?.name ?? 'Error', message: String(err?.message ?? err).slice(0, 800) });
15
16const spawnPeer = async ($) => {
17 try {
18 const resolved = await $.agent.spawn({
19 subagentType: `${PLUGIN}:peer`,
20 description: 'probe peer',
21 prompt: 'Reply OK.',
22 });
23 state.spawn = { agentId: resolved?.agentId ?? null, resolved };
24 } catch (err) {
25 state.spawn = { agentId: null, rejected: errOf(err) };
26 }
27 if (state.spawn.agentId) {
28 try {
29 state.cleanup = await $.tool.call({ tool: 'TaskStop', task_id: state.spawn.agentId });
30 } catch (err) {
31 state.cleanup = { rejected: errOf(err) };
32 }
33 }
34};
35
36export const register = (on) => {
37 on('session.start', async ($, e, next) => {
38 try {
39 await $.agent.register({
40 name: 'peer',
41 description: 'Cap probe agent of a second plugin. The probe spawns it; do not delegate to it.',
42 prompt: `${HOLD}. Reply OK. Do not call tools.`,
43 tools: [],
44 model: 'haiku',
45 omitClaudeMd: true,
46 background: true,
47 maxTurns: 1,
48 });
49 } catch (err) {
50 state.registerError = errOf(err);
51 }
52 return next(e);
53 });
54
55 on('agent.offer', async ($, e, next) =>
56 String(e.agent ?? '').startsWith(`${PLUGIN}:`) ? { isOffered: false } : next(e)
57 );
58
59 on('turn.start', async ($, e, next) => {
60 if (!e.agentId) {
61 lastText = String(e.text ?? '');
62 }
63 return next(e);
64 });
65
66 on('turn.complete', async ($, e, next) => {
67 const result = await next(e);
68 if (!e.agentId && state.phase === 'idle' && lastText.includes(MARKER)) {
69 state.phase = 'acting';
70 state.at = Date.now();
71 await spawnPeer($);
72 state.phase = 'done';
73 await $.fs.write(FILE, JSON.stringify(state)).catch(() => undefined);
74 }
75 return result;
76 });
77};
78