read_page_html

Instructions

Implementation Reference

• src/tools/devtools-sources.ts:6-26 (registration)

  Registers the 'read_page_html' MCP tool with the server, defining its name, description, input schema (optional tabId and apiKey), and handler that sends a command via WebSocket bridge.

  export function registerDevtoolsSourcesTools(server: McpServer, bridge: WebSocketBridge) {
    server.tool(
      'read_page_html',
      'Read the full HTML source of the current page',
      {
        tabId: z.number().optional().describe('Target tab ID (defaults to active tab)'),
        apiKey: z.string().optional().describe('API key for authentication'),
      },
      async ({ tabId, apiKey }) => {
        const result = await bridge.sendCommand({
          command: 'read_page_html',
          params: {},
          tabId,
          apiKey,
        });
        if (!result.success) {
          return { content: [{ type: 'text', text: `Error: ${result.error?.message}` }], isError: true };
        }
        return { content: [{ type: 'text', text: result.data as string }] };
      }
    );

• src/tools/devtools-sources.ts:14-25 (handler)

  The handler function that executes the tool: sends a 'read_page_html' command via WebSocketBridge.sendCommand and returns the HTML as text, or an error message if the command fails.

  async ({ tabId, apiKey }) => {
    const result = await bridge.sendCommand({
      command: 'read_page_html',
      params: {},
      tabId,
      apiKey,
    });
    if (!result.success) {
      return { content: [{ type: 'text', text: `Error: ${result.error?.message}` }], isError: true };
    }
    return { content: [{ type: 'text', text: result.data as string }] };
  }

• src/tools/devtools-sources.ts:10-13 (schema)

  Input schema for the tool: tabId (optional number) and apiKey (optional string), validated with Zod.

  {
    tabId: z.number().optional().describe('Target tab ID (defaults to active tab)'),
    apiKey: z.string().optional().describe('API key for authentication'),
  },

• src/websocket-bridge.ts:63-103 (helper)

  The WebSocketBridge.sendCommand method that forwards the 'read_page_html' command to the Chrome extension via WebSocket and returns the response.

  async sendCommand(cmd: BridgeCommand): Promise<BridgeResponse> {
    if (!this.isConnected()) {
      return {
        success: false,
        error: {
          code: 'NOT_CONNECTED',
          message: 'Chrome extension is not connected. Ensure the extension is installed, enabled, and the browser is running.',
        },
      };
    }
  
    const id = crypto.randomUUID();
    const timeout = cmd.timeout ?? DEFAULT_TIMEOUT;
  
    return new Promise<BridgeResponse>((resolve, reject) => {
      const timer = setTimeout(() => {
        this.pending.delete(id);
        resolve({
          success: false,
          error: {
            code: 'TIMEOUT',
            message: `Command '${cmd.command}' timed out after ${timeout}ms`,
          },
        });
      }, timeout);
  
      this.pending.set(id, { resolve, reject, timer });
  
      const message = {
        id,
        type: 'request',
        command: cmd.command,
        params: cmd.params,
        tabId: cmd.tabId,
        apiKey: cmd.apiKey,
        timestamp: Date.now(),
      };
  
      this.client!.send(JSON.stringify(message));
    });
  }

• src/tools/index.ts:12-12 (helper)

  Import of registerDevtoolsSourcesTools from devtools-sources.ts, called at line 39 to register the tool.

  import { registerDevtoolsSourcesTools } from './devtools-sources.js';