Method startDirect

src/mcp/index.ts:351–391

Single-process stdio MCP session — the pre-issue-#411 code path.

(reason: string)

  /** Single-process stdio MCP session — the pre-issue-#411 code path. */
  private async startDirect(reason: string): Promise<void> {
    if (reason && process.env.CODEGRAPH_MCP_DEBUG) {
      process.stderr.write(`[CodeGraph MCP] Direct mode: ${reason}.\n`);
    }
    this.engine = new MCPEngine();
    const transport = new StdioTransport();
    this.session = new MCPSession(transport, this.engine, {
      explicitProjectPath: this.projectPath,
    });

    if (this.projectPath) {
      // Background init so the initialize response stays fast (#172).
      void this.engine.ensureInitialized(this.projectPath);
    }

    this.session.start();

    // Detect parent-process death — same logic as pre-refactor. When stdin
    // closes we go through StdioTransport's `process.exit(0)` already, but
    // SIGKILL of the parent doesn't reliably close stdin on Linux (#277).
    // Also treat a stdin `'error'` (a socket-backed stdin can fail with
    // ECONNRESET/hangup instead of a clean close) as shutdown, and destroy the
    // stream so a hung fd can't busy-spin the event loop (#799).
    treatStdinFailureAsShutdown(() => this.stop());
    // Backstop for a launch abandoned during startup (#1185): launcher killed
    // before EARLY_PPID could see it + host holding our pipes open. A server
    // that never receives a byte of MCP traffic isn't serving anyone. Armed
    // after session.start() attached the real stdin consumer.
    armStartupHandshakeTimeout(() => {
      process.stderr.write(
        '[CodeGraph MCP] No MCP traffic since startup; assuming an abandoned launch and shutting down (#1185). ' +
        'Tune with CODEGRAPH_STARTUP_HANDSHAKE_TIMEOUT_MS (0 disables).\n'
      );
      this.stop();
    });

    this.mode = 'direct';
    this.installSignalHandlers();
    this.installPpidWatchdog();
    this.livenessWatchdog = installMainThreadWatchdog(watchdogProgressPaths(resolveDaemonRoot(this.projectPath)));
  }

  /**
   * Run as the detached shared daemon (process spawned with