Skip to main content
Glama
afshawnlotfi

Configurable Puppeteer MCP Server

by afshawnlotfi

puppeteer_screenshot

Capture screenshots of web pages or specific elements using browser automation. Specify dimensions and CSS selectors to document page states for testing or analysis.

Instructions

Take a screenshot of the current page or a specific element

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
nameYesName for the screenshot
selectorNoCSS selector for element to screenshot
widthNoWidth in pixels (default: 800)
heightNoHeight in pixels (default: 600)

Implementation Reference

  • Handler for puppeteer_screenshot tool: sets viewport, captures screenshot of page or element using Puppeteer, handles errors, stores screenshot, notifies resource change, and returns confirmation text and image content.
    case "puppeteer_screenshot": {
      const width = args.width ?? 800;
      const height = args.height ?? 600;
      await page.setViewport({ width, height });
    
      const screenshot = await (args.selector ?
        (await page.$(args.selector))?.screenshot({ encoding: "base64" }) :
        page.screenshot({ encoding: "base64", fullPage: false }));
    
      if (!screenshot) {
        return {
          content: [{
            type: "text",
            text: args.selector ? `Element not found: ${args.selector}` : "Screenshot failed",
          }],
          isError: true,
        };
      }
    
      screenshots.set(args.name, screenshot as string);
      server.notification({
        method: "notifications/resources/list_changed",
      });
    
      return {
        content: [
          {
            type: "text",
            text: `Screenshot '${args.name}' taken at ${width}x${height}`,
          } as TextContent,
          {
            type: "image",
            data: screenshot,
            mimeType: "image/png",
          } as ImageContent,
        ],
        isError: false,
      };
    }
  • Input schema defining parameters for puppeteer_screenshot: name (required), optional selector, width, height.
    inputSchema: {
      type: "object",
      properties: {
        name: { type: "string", description: "Name for the screenshot" },
        selector: { type: "string", description: "CSS selector for element to screenshot" },
        width: { type: "number", description: "Width in pixels (default: 800)" },
        height: { type: "number", description: "Height in pixels (default: 600)" },
      },
      required: ["name"],
    },
  • index.ts:30-43 (registration)
    Registration of puppeteer_screenshot tool in the TOOLS array, including name, description, and input schema, used for listing tools.
    {
      name: "puppeteer_screenshot",
      description: "Take a screenshot of the current page or a specific element",
      inputSchema: {
        type: "object",
        properties: {
          name: { type: "string", description: "Name for the screenshot" },
          selector: { type: "string", description: "CSS selector for element to screenshot" },
          width: { type: "number", description: "Width in pixels (default: 800)" },
          height: { type: "number", description: "Height in pixels (default: 600)" },
        },
        required: ["name"],
      },
    },
Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries full burden for behavioral disclosure. It states the action but lacks critical details: whether this is a read-only operation, if it requires specific page states, what happens on failure (e.g., invalid selector), or the output format (e.g., image data, file path). This is inadequate for a tool with potential side effects.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence that directly states the tool's purpose without unnecessary words. It's appropriately sized and front-loaded with the core functionality.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with 4 parameters, no annotations, and no output schema, the description is insufficient. It doesn't explain what the tool returns (e.g., image data, file path), error conditions, or dependencies on other tools (like puppeteer_navigate). Given the complexity and lack of structured data, more behavioral context is needed.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all parameters thoroughly. The description adds minimal value beyond the schema—it implies 'selector' targets elements and 'width/height' control dimensions, but doesn't provide additional context like selector syntax examples or dimension constraints.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action ('Take a screenshot') and target ('current page or a specific element'), providing a specific verb+resource. However, it doesn't explicitly distinguish this tool from its siblings (e.g., puppeteer_click, puppeteer_evaluate), which are different interaction types rather than direct alternatives for screenshotting.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing a page loaded via puppeteer_navigate first), exclusions, or contextual advice for choosing between full-page vs. element screenshots.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Install Server

Other Tools

Latest Blog Posts

MCP directory API

We provide all the information about MCP servers via our MCP API.

curl -X GET 'https://glama.ai/api/mcp/v1/servers/afshawnlotfi/mcp-configurable-puppeteer'

If you have feedback or need assistance with the MCP directory API, please join our Discord server