AI Development Pipeline MCP

Instructions

Implementation Reference

• local-mcp-server.ts:111-119 (handler)

  The main handler function for the 'check_file_exists' tool. It validates the input path using validatePath, then uses fs.existsSync to check if the file exists, returning a text response indicating existence or not.

  async ({ path }) => {
    try {
      const safePath = validatePath(path);
      const exists = fs.existsSync(safePath);
      return { content: [{ type: 'text', text: exists ? 'File exists' : 'File does not exist' }] };
    } catch (err: any) {
      return { content: [{ type: 'text', text: `File check error: ${err.message}` }] };
    }
  }

• local-mcp-server.ts:107-120 (registration)

  Registration of the 'check_file_exists' tool on the MCP server, including name, description, schema, and handler.

  server.tool(
    'check_file_exists',
    'Check if a local file exists (restricted to workspace directory)',
    { path: z.string() },
    async ({ path }) => {
      try {
        const safePath = validatePath(path);
        const exists = fs.existsSync(safePath);
        return { content: [{ type: 'text', text: exists ? 'File exists' : 'File does not exist' }] };
      } catch (err: any) {
        return { content: [{ type: 'text', text: `File check error: ${err.message}` }] };
      }
    }
  );

• local-mcp-server.ts:110-110 (schema)

  Input schema for the tool: requires a 'path' parameter as a string, validated with Zod.

  { path: z.string() },

• local-mcp-server.ts:15-21 (helper)

  Helper function used by the tool to validate and resolve the file path, preventing path traversal attacks by ensuring it stays within the workspace root.

  function validatePath(filePath: string): string {
    const resolvedPath = path.resolve(WORKSPACE_ROOT, filePath);
    if (!resolvedPath.startsWith(WORKSPACE_ROOT)) {
      throw new Error('Path traversal detected - access denied');
    }
    return resolvedPath;
  }