AI Development Pipeline MCP

Instructions

Implementation Reference

• local-mcp-server.ts:60-68 (handler)

  Handler function that validates the file path using validatePath helper and writes the provided content to the file using fs.writeFileSync, returning success or error message.

  async ({ path, content }) => {
    try {
      const safePath = validatePath(path);
      fs.writeFileSync(safePath, content, 'utf8');
      return { content: [{ type: 'text', text: `File written: ${path}` }] };
    } catch (err: any) {
      return { content: [{ type: 'text', text: `File write error: ${err.message}` }] };
    }
  }

• local-mcp-server.ts:59-59 (schema)

  Input schema using Zod: requires 'path' (string) for the file location and 'content' (string) for the file contents.

  { path: z.string(), content: z.string() },

• local-mcp-server.ts:56-69 (registration)

  Registers the 'write_project_file' tool on the MCP server with name, description, input schema, and handler function.

  server.tool(
    'write_project_file',
    'Write to a local file in the VS Code workspace (restricted to workspace directory)',
    { path: z.string(), content: z.string() },
    async ({ path, content }) => {
      try {
        const safePath = validatePath(path);
        fs.writeFileSync(safePath, content, 'utf8');
        return { content: [{ type: 'text', text: `File written: ${path}` }] };
      } catch (err: any) {
        return { content: [{ type: 'text', text: `File write error: ${err.message}` }] };
      }
    }
  );

• local-mcp-server.ts:15-21 (helper)

  Security helper that resolves and validates the file path to ensure it stays within the workspace root, preventing path traversal attacks.

  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;
  }