Browser Agent MCP

Instructions

Implementation Reference

• src/executor.ts:404-428 (handler)

  The handler function that executes the browser_select tool using Playwright's page.selectOption method to select a dropdown option.

  async function handleBrowserSelect(page: Page, args: any): Promise<{ toolResult: CallToolResult }> {
    try {
      await page.waitForSelector(args.selector);
      await page.selectOption(args.selector, args.value);
      return {
        toolResult: {
          content: [{
            type: "text",
            text: `Selected option ${args.value} in ${args.selector}`,
          }],
          isError: false,
        },
      };
    } catch (error) {
      return {
        toolResult: {
          content: [{
            type: "text",
            text: `Selection failed on ${args.selector}: ${(error as Error).message}`,
          }],
          isError: true,
        },
      };
    }
  }

• src/tools.ts:96-107 (schema)

  Input schema and metadata definition for the browser_select tool.

  {
    name: "browser_select",
    description: "Select an option from a dropdown menu",
    inputSchema: {
      type: "object",
      properties: {
        selector: { type: "string", description: "CSS selector for select element" },
        value: { type: "string", description: "Value or label to select" }
      },
      required: ["selector", "value"]
    }
  },

• src/tools.ts:3-12 (registration)

  Registers browser_select as part of the browser tools list used for tool dispatching.

  export const BROWSER_TOOLS = [
    "browser_navigate",
    "browser_screenshot",
    "browser_click",
    "browser_fill",
    "browser_select",
    "browser_hover",
    "browser_evaluate",
    "browser_set_viewport"
  ];

• src/executor.ts:200-201 (registration)

  Switch case in executeToolCall that routes browser_select calls to its handler.

  case "browser_select":
    return await handleBrowserSelect(activePage!, args);

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

  MCP server handler for listing available tools, which includes browser_select.

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