browser-use MCP server

Instructions

Implementation Reference

• src/browser_use/server.py:119-150 (handler)

  The handler function for tool calls that implements the logic for 'add-note': validates arguments, stores the note in the global 'notes' dictionary, notifies clients of resource changes, and returns a confirmation message.

  @server.call_tool()
  async def handle_call_tool(
      name: str, arguments: dict | None
  ) -> list[types.TextContent | types.ImageContent | types.EmbeddedResource]:
      """
      Handle tool execution requests.
      Tools can modify server state and notify clients of changes.
      """
      if name != "add-note":
          raise ValueError(f"Unknown tool: {name}")
  
      if not arguments:
          raise ValueError("Missing arguments")
  
      note_name = arguments.get("name")
      content = arguments.get("content")
  
      if not note_name or not content:
          raise ValueError("Missing name or content")
  
      # Update server state
      notes[note_name] = content
  
      # Notify clients that resources have changed
      await server.request_context.session.send_resource_list_changed()
  
      return [
          types.TextContent(
              type="text",
              text=f"Added note '{note_name}' with content: {content}",
          )
      ]

• src/browser_use/server.py:107-114 (schema)

  JSON schema defining the input arguments for the 'add-note' tool: requires 'name' and 'content' as strings.

  inputSchema={
      "type": "object",
      "properties": {
          "name": {"type": "string"},
          "content": {"type": "string"},
      },
      "required": ["name", "content"],
  },

• src/browser_use/server.py:103-116 (registration)

  The 'add-note' tool is registered in the @server.list_tools() handler by returning it in the list of available tools.

  return [
      types.Tool(
          name="add-note",
          description="Add a new note",
          inputSchema={
              "type": "object",
              "properties": {
                  "name": {"type": "string"},
                  "content": {"type": "string"},
              },
              "required": ["name", "content"],
          },
      )
  ]

• src/browser_use/server.py:7-8 (helper)

  Global dictionary used to store notes persistently across tool calls.

  # Store notes as a simple key-value dict to demonstrate state management
  notes: dict[str, str] = {}