screenshot

Instructions

Implementation Reference

• src/tools/observation.ts:245-261 (handler)

  Tool handler for 'screenshot' — calls client.screenshot() and returns base64 PNG image result.

  server.tool(
    "screenshot",
    "Take visual screenshot in base64 PNG. Use ONLY for visual verification (CSS, layout, proof). Prefer snapshot for most tasks — much more token-efficient.",
    {
      tabId: z.string().min(1).describe("Tab ID from create_tab")
    },
    async (input: unknown) => {
      try {
        const parsed = z.object({ tabId: z.string().min(1).describe("Tab ID from create_tab") }).parse(input);
        const tracked = getTrackedTab(parsed.tabId);
        const screenshotBuffer = await deps.client.screenshot(parsed.tabId, tracked.userId);
        incrementToolCall(parsed.tabId);
        return imageResult(screenshotBuffer.toString("base64"));
      } catch (error) {
        return toErrorResult(error);
      }
    }

• src/tools/observation.ts:248-249 (schema)

  Input schema for screenshot tool — requires tabId string.

  {
    tabId: z.string().min(1).describe("Tab ID from create_tab")

• src/tools/observation.ts:245-262 (registration)

  Registration of the 'screenshot' tool via server.tool()

  server.tool(
    "screenshot",
    "Take visual screenshot in base64 PNG. Use ONLY for visual verification (CSS, layout, proof). Prefer snapshot for most tasks — much more token-efficient.",
    {
      tabId: z.string().min(1).describe("Tab ID from create_tab")
    },
    async (input: unknown) => {
      try {
        const parsed = z.object({ tabId: z.string().min(1).describe("Tab ID from create_tab") }).parse(input);
        const tracked = getTrackedTab(parsed.tabId);
        const screenshotBuffer = await deps.client.screenshot(parsed.tabId, tracked.userId);
        incrementToolCall(parsed.tabId);
        return imageResult(screenshotBuffer.toString("base64"));
      } catch (error) {
        return toErrorResult(error);
      }
    }
  );

• src/client.ts:652-660 (helper)

  Client method that fetches screenshot binary from the API.

  async screenshot(tabId: string, userId: string): Promise<Buffer> {
    const binary = await this.requestBinary(
      `/tabs/${encodeURIComponent(tabId)}/screenshot?userId=${encodeURIComponent(userId)}`,
      {
      method: "GET"
      }
    );
    return Buffer.from(binary);
  }

• src/errors.ts:51-55 (helper)

  Helper function to wrap base64 PNG into a ToolResult with image content type.

  export function imageResult(base64Png: string): ToolResult {
    return {
      content: [{ type: "image", data: base64Png, mimeType: "image/png" }]
    };
  }