Function startPpidWatchdogNoSocket

src/mcp/proxy.ts:417–438

PPID watchdog for the local-handshake proxy — same #277 logic as * startPpidWatchdog but with no socket to close (the caller's shutdown * handles teardown).

(onDeath: () => void)

 *  {@link startPpidWatchdog} but with no socket to close (the caller's shutdown
 *  handles teardown). */
function startPpidWatchdogNoSocket(onDeath: () => void): void {
  const pollMs = parsePollMs(process.env.CODEGRAPH_PPID_POLL_MS);
  if (pollMs <= 0) return;
  // Baseline from the CLI entry's earliest capture, not process.ppid here —
  // a launcher killed during our first ~100ms would otherwise leave the
  // baseline at 1 and blind the divergence check forever (#1185).
  const originalPpid = EARLY_PPID;
  const hostPpid = parseHostPpid(process.env[HOST_PPID_ENV]);
  const timer = setInterval(() => {
    const reason = supervisionLostReason({
      originalPpid,
      currentPpid: process.ppid,
      hostPpid,
      isAlive: isProcessAliveLocal,
    });
    if (reason) {
      process.stderr.write(`[CodeGraph MCP] Parent process exited (${reason}); shutting down.\n`);
      onDeath();
    }
  }, pollMs);
  timer.unref?.();
}

/**
 * Read one CRLF/LF-terminated JSON line from the socket, parse it as the