One shared, detached daemon per project root: every `codegraph serve --mcp` is a thin stdio<->socket proxy (Unix socket / Windows named pipe) to it, so N agents in one repo share a single file watcher, SQLite connection, and tree-sitter warm-up instead of N copies. The daemon outlives any single session and reaps via client-refcount + idle timeout; `CODEGRAPH_NO_DAEMON=1` opts out.
Hardened during review: detached-process lifecycle (preserves the #277 watchdog via the proxy; the daemon no longer orphans on host SIGKILL), atomic lockfile + pid-verified stale-clear (no double-daemon on concurrent startup), realpath root canonicalization. Validated on macOS, Linux (Docker - 3x fewer inotify watches for 3 agents), and Windows (named pipes); A/B confirms byte-identical tool output vs direct mode. Closes#411.
Co-Authored-By: Colby McHenry <me@colbymchenry.com>
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Add a PPID watchdog to the MCP server so a `codegraph serve --mcp` child terminates when its host (Claude Code, opencode, …) is force-killed — OOM killer, `kill -9`, container teardown — and the stdin close handlers don't fire. The child would otherwise linger indefinitely, holding inotify watches, file descriptors, and the SQLite WAL.
Also propagates the host PID across the `--liftoff-only` re-exec (CODEGRAPH_HOST_PPID) so the watchdog reaps the orphan on the from-source path too, not just the bundled launcher. Poll interval is CODEGRAPH_PPID_POLL_MS (default 5000ms, 0 disables).
Resolves#277.
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
