Method executeThirdPartyDeveloperTool

src/McpPage.ts:148–335

(
    toolName: string,
    params: Record<string, unknown>,
    response: Response,
  )

  }

  async executeThirdPartyDeveloperTool(
    toolName: string,
    params: Record<string, unknown>,
    response: Response,
  ): Promise<void> {
    // Creates array of ElementHandles from the UIDs in the params.
    // We do not replace the uids with the ElementsHandles yet, because
    // the `evaluate` function only turns them into DOM elements if they
    // are passed as non-nested arguments.
    const handles: ElementHandle[] = [];
    for (const value of Object.values(params)) {
      if (
        value instanceof Object &&
        'uid' in value &&
        typeof value.uid === 'string' &&
        Object.keys(value).length === 1
      ) {
        handles.push(await this.getElementByUid(value.uid));
      }
    }

    const result = await this.pptrPage.evaluate(
      async (name, args, ...elements) => {
        // Replace the UIDs with DOM elements.
        for (const [key, value] of Object.entries(args)) {
          if (
            value instanceof Object &&
            'uid' in value &&
            typeof value.uid === 'string' &&
            Object.keys(value).length === 1
          ) {
            args[key] = elements.shift();
          }
        }

        if (!window.__dtmcp?.executeTool) {
          throw new Error('No tools found on the page');
        }
        const toolResult = await window.__dtmcp.executeTool(name, args);

        const stashDOMElement = (el: Element) => {
          if (!window.__dtmcp) {
            window.__dtmcp = {};
          }
          if (window.__dtmcp.stashedElements === undefined) {
            window.__dtmcp.stashedElements = [];
          }
          window.__dtmcp.stashedElements.push(el);
          return {
            stashedId: `stashed-${window.__dtmcp.stashedElements.length - 1}`,
          };
        };

        const ancestors: unknown[] = [];
        // Recursively walks the tool result:
        // - Replaces DOM elements with an ID and stashes the DOM element on the window object
        // - Replaces non-plain objects with a string representation of the object
        // - Replaces circular references with the string '<Circular reference>'