Browser Agent MCP

Instructions

Implementation Reference

• src/executor.ts:512-541 (handler)

  Core implementation of the 'api_get' tool: performs a GET request using Playwright APIRequestContext, handles headers, fetches response data, and formats output including status and body.

  async function handleApiGet(client: APIRequestContext, args: any): Promise<{ toolResult: CallToolResult }> {
    try {
      const options = args.headers ? { headers: args.headers } : undefined;
      const response = await client.get(args.url, options);
      const responseData = await getResponseData(response);
  
      return {
        toolResult: {
          content: [
            {
              type: "text",
              text: `GET ${args.url} - Status: ${response.status()}`,
            },
            ...responseData
          ],
          isError: false,
        },
      };
    } catch (error) {
      return {
        toolResult: {
          content: [{
            type: "text",
            text: `GET request failed: ${(error as Error).message}`,
          }],
          isError: true,
        },
      };
    }
  }

• src/tools.ts:131-146 (schema)

  Tool definition for 'api_get' including input schema specifying required 'url' and optional 'headers'.

  {
    name: "api_get",
    description: "Perform a GET request to an API endpoint",
    inputSchema: {
      type: "object",
      properties: {
        url: { type: "string", description: "API endpoint URL" },
        headers: { 
          type: "object", 
          description: "Request headers",
          additionalProperties: { type: "string" }
        }
      },
      required: ["url"]
    }
  },

• src/executor.ts:209-210 (registration)

  Registration and dispatch of 'api_get' handler in the main executeToolCall switch statement.

  case "api_get":
    return await handleApiGet(apiClient!, args);

• src/executor.ts:144-161 (helper)

  Helper function used by api_get to parse and format API response body as text content, preferring pretty-printed JSON.

  async function getResponseData(response: any): Promise<TextContent[]> {
    const contentType = response.headers()['content-type'] || '';
    let responseText: string;
    if (contentType.includes('application/json')) {
      try {
        const json = await response.json();
        responseText = JSON.stringify(json, null, 2);
      } catch (e) {
        responseText = await response.text();
      }
    } else {
      responseText = await response.text();
    }
    return [{
      type: "text",
      text: `Response body:\n${responseText}`,
    } as TextContent];
  }

• src/handlers.ts:61-63 (registration)

  MCP server handler for listing tools, which includes the 'api_get' tool from registerTools().

  server.setRequestHandler(ListToolsRequestSchema, async () => ({
    tools: tools,
  }));