c22558c67a
Per spec/agent-watcher.md §4. TypeScript/Node implementation living in
mcp-watcher/ subdirectory, parallel to Layer 1 Collector at repo root.
What lands:
- Core MCP server (src/server.ts) with experimental['claude/channel']:{}
+ tools:{} capability declarations, stdio transport, channel-event
notifier wired through the inbox watcher.
- Identity resolution mirroring agent-ping's layered model
(PING_AGENT_IDENTITY env, $CLAUDE_HOME/ping-agent, ~/.ping-agent).
- Inbox reader with HWM tracking, sentinel deferral (warn-after-3),
atomic HWM writes via tmp+rename.
- chokidar-backed file watcher with coalesced drain, urgent-first
ordering, recentEvents map for tool sender lookup.
- Three reply tools (ack / respond / mark_handled) with cross-host
write discipline (writes to local inbox files; Syncthing replicates).
- Sentinel file (.<agent>.watcher-active) for hook coexistence per
spec §4.3 — agent-ping hook stands down when the watcher is in
charge of delivery on this host. Sentinel + hwm in .stignore.
- 35 unit tests passing (vitest): inbox parsing, HWM round-trip,
sentinel deferral semantics, identity layers, tool I/O, watcher
drain + ordering + restart-from-hwm.
- install.sh (Angus-executed, rule-2 compliant) installs deps,
builds, symlinks ~/.local/bin/agent-watcher-mcp, prints mcp.json
registration snippet for paste.
- README documents launch flag, sandbox CLAUDE_HOME pattern,
hook coexistence, observability, v2 limitations.
Not yet:
- Integration test against a real Claude Code session — gated on
Angus spinning up a sandbox CC session on the VPS with
CLAUDE_HOME=~/.claude-sandbox.
- agent-ping hook update to read the sentinel and stand down.
Separate small PR against agent-ping.
Interface contract with Layer 1: the inbox JSONL line shape from
inbox.ts::PingEvent matches inbox.Event in the Collector — bit-
identical reads regardless of source.
98 lines
3.2 KiB
Markdown
98 lines
3.2 KiB
Markdown
# agent-watcher-mcp (Layer 2)
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The MCP Watcher: a Claude Code stdio MCP server that surfaces ping-inbox
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events into your Claude Code session via Channels, and exposes reply tools
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(`ack` / `respond` / `mark_handled`) so Claude can react.
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Spec: `../spec/agent-watcher.md` §4.
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## What it does
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1. Resolves identity (env / `$CLAUDE_HOME/ping-agent` / `~/.ping-agent`).
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2. Writes `pings/.<agent>.watcher-active` so the existing agent-ping
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`UserPromptSubmit` hook stands down on this host.
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3. Watches `pings/<agent>.inbox` via inotify (chokidar).
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4. On change, drains unread pings (since HWM), applies sentinel
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deferral (warn-after-3), and emits each as a
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`notifications/claude/channel` event.
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5. Exposes three MCP tools so Claude can ack, respond, or mark a ping
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handled.
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6. Removes the sentinel on graceful shutdown.
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## Install
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Per CLAUDE.md rule #2, the agent does not install on itself. A human
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runs:
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```bash
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cd /path/to/agent-watcher/mcp-watcher
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./install.sh
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```
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This installs deps, builds, symlinks the binary into `~/.local/bin/`,
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adds `.stignore` patterns, and prints the `mcp.json` snippet to paste
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into Claude Code's config.
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## Launch
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Channels is in research preview. Start Claude Code with:
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```bash
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claude --dangerously-load-development-channels server:agent-watcher
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```
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## Sandbox testing
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To run a separate Claude Code session with a different identity (so it
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won't compete with the default `~/.ping-agent` for inbox reads):
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```bash
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mkdir -p ~/.claude-sandbox
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echo sandbox > ~/.claude-sandbox/ping-agent
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CLAUDE_HOME=~/.claude-sandbox \
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claude --dangerously-load-development-channels server:agent-watcher
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```
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The sandbox session reads `pings/sandbox.inbox` and writes
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`pings/.sandbox.watcher-active` — fully isolated from prod.
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## How it interacts with agent-ping
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The `agent-ping` UserPromptSubmit hook checks for the sentinel file
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`pings/.<agent>.watcher-active` at startup. If the file is present and
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the PID inside is alive, the hook stands down — the watcher is the
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delivery primitive. If the watcher exits (graceful or crash with stale
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sentinel cleared by the hook's age check), the hook resumes
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async-on-next-prompt delivery.
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This means **you can run with the watcher OR the hook OR both
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configured** — the sentinel arbitrates.
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## Tests
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```bash
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npm test # unit tests via vitest (35 currently passing)
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npm run typecheck # tsc --noEmit
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npm run build # tsc → dist/
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```
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## Observability
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- Logs to stderr (visible via `claude --debug` or the Claude Code MCP
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debug log at `~/.claude/debug/<session-id>.txt`).
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- Sentinel file content includes PID + start time for the hook's
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age/liveness check.
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## Limitations / v2
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- Sentinel hook coexistence requires the agent-ping hook to know how
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to read the sentinel. PR pending against `agent-ping` to add the
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check.
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- No reconnection / restart on Claude Code session restart — Claude
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Code spawns the subprocess anew each session, so the watcher
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re-drains from HWM cleanly.
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- One watcher process per agent identity. Two sessions with the same
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identity contending on the same inbox is undefined behaviour
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(use `CLAUDE_HOME` to scope identities).
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- Channels is research preview; if the API changes, expect to update
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the meta-key sanitization or notification shape.
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