fidelity_screenshot

Instructions

Implementation Reference

• src/index.ts:490-539 (registration)

  Registers the 'fidelity_screenshot' tool on the MCP server with Zod schema for optional 'url' parameter and handler that takes a screenshot.

  server.tool(
    "fidelity_screenshot",
    "Take a screenshot of the current Fidelity browser page. Useful for debugging when tools return unexpected results.",
    {
      url: z
        .string()
        .optional()
        .describe(
          "Optional URL to navigate to before taking the screenshot. If omitted, captures the current page."
        ),
    },
    async ({ url }) => {
      try {
        const page = await getPage();
  
        if (url) {
          await page.goto(url, { waitUntil: "domcontentloaded" });
          const { waitForLoadingCompleteDouble } = await import("./browser.js");
          await waitForLoadingCompleteDouble(page, 30000);
        }
  
        const screenshotBuffer = await page.screenshot({ fullPage: true });
        const base64 = screenshotBuffer.toString("base64");
  
        return {
          content: [
            {
              type: "text",
              text: `Screenshot of: ${page.url()}`,
            },
            {
              type: "image",
              data: base64,
              mimeType: "image/png",
            },
          ],
        };
      } catch (e) {
        return {
          content: [
            {
              type: "text",
              text: `Screenshot failed: ${e instanceof Error ? e.message : String(e)}`,
            },
          ],
          isError: true,
        };
      }
    }
  );

• src/index.ts:501-538 (handler)

  The handler function that gets the browser page, optionally navigates to a URL, waits for loading to complete, takes a full-page screenshot, and returns it as base64-encoded image.

  async ({ url }) => {
    try {
      const page = await getPage();
  
      if (url) {
        await page.goto(url, { waitUntil: "domcontentloaded" });
        const { waitForLoadingCompleteDouble } = await import("./browser.js");
        await waitForLoadingCompleteDouble(page, 30000);
      }
  
      const screenshotBuffer = await page.screenshot({ fullPage: true });
      const base64 = screenshotBuffer.toString("base64");
  
      return {
        content: [
          {
            type: "text",
            text: `Screenshot of: ${page.url()}`,
          },
          {
            type: "image",
            data: base64,
            mimeType: "image/png",
          },
        ],
      };
    } catch (e) {
      return {
        content: [
          {
            type: "text",
            text: `Screenshot failed: ${e instanceof Error ? e.message : String(e)}`,
          },
        ],
        isError: true,
      };
    }
  }

• src/index.ts:493-500 (schema)

  Zod schema defining the optional 'url' input parameter with description.

  {
    url: z
      .string()
      .optional()
      .describe(
        "Optional URL to navigate to before taking the screenshot. If omitted, captures the current page."
      ),
  },

• src/browser.ts:80-87 (helper)

  The getPage() helper function used by the handler to retrieve the current browser page; throws if browser not initialized.

  export async function getPage(): Promise<Page> {
    if (!page || page.isClosed()) {
      throw new Error(
        "Browser not initialized. Call fidelity_login first."
      );
    }
    return page;
  }