Steel MCP Server

Instructions

Implementation Reference

• src/index.ts:871-899 (handler)

  The function that implements the core logic of the 'save_unmarked_screenshot' tool. It optionally generates a resourceName, unmarks the page to remove bounding boxes, captures a screenshot, stores it in the 'screenshots' map, and returns a success message with the resource URI.

  async function handleSaveUnmarkedScreenshot(
    page: Page,
    args: any
  ): Promise<CallToolResult> {
    let { resourceName } = args;
    if (!resourceName) {
      resourceName = `unmarked_screenshot_${Date.now()}`;
    }
  
    // Unmark the page to remove bounding boxes
    await page.evaluate(() => {
      if (typeof (window as any).unmarkPage === "function") {
        (window as any).unmarkPage();
      }
    });
  
    const buffer = await page.screenshot();
    screenshots.set(resourceName, Buffer.from(buffer));
  
    return {
      isError: false,
      content: [
        {
          type: "text",
          text: `Unmarked screenshot saved as resource screenshot://${resourceName}`,
        },
      ],
    };
  }

• src/index.ts:585-595 (schema)

  Input schema definition for the tool, specifying an optional 'resourceName' parameter of type string.

  inputSchema: {
    type: "object",
    properties: {
      resourceName: {
        type: "string",
        description:
          "The name under which the unmarked screenshot will be saved as a resource (e.g. 'before_login'). If not provided, one will be generated.",
      },
    },
    required: [],
  },

• src/index.ts:581-596 (registration)

  The tool registration entry in the TOOLS array, including name, description, and inputSchema, which is returned by the ListTools MCP handler.

  {
    name: "save_unmarked_screenshot",
    description:
      "Capture a screenshot without bounding boxes and store it as a resource. Provide a resourceName to identify the screenshot. It's useful for when you want to view a page unobstructed by annotations or the user asks for a screenshot of the page.",
    inputSchema: {
      type: "object",
      properties: {
        resourceName: {
          type: "string",
          description:
            "The name under which the unmarked screenshot will be saved as a resource (e.g. 'before_login'). If not provided, one will be generated.",
        },
      },
      required: [],
    },
  },

• src/index.ts:940-942 (helper)

  The switch case in the main tool dispatcher (handleToolCall) that routes calls to the specific handler function.

  case "save_unmarked_screenshot":
    result = await handleSaveUnmarkedScreenshot(page, args);
    break;