feat: add official way to use MCP Tools within a CrewBase

Added a standard way to define and use MCP server tools inside a CrewBase class.
This was necessary because existing methods don't work in this context due to lifecycle mismatches.
MCP tools run asynchronously and start an event loop, which causes the instance state to become desynchronized from the crew.
This change ensures proper integration by aligning the MCP server lifecycle with the CrewBase instance.

docs/mcp/overview.mdx

@@ -101,6 +101,41 @@ with MCPServerAdapter(server_params) as mcp_tools:
     )
     # ... rest of your crew setup ...
 ```
+
+## Using with CrewBase
+
+To use MCPServer tools within a CrewBase class, use the `mcp_tools` method. Server configurations should be provided via the mcp_server_params attribute. You can pass either a single configuration or a list of multiple server configurations.
+
+```python
+@CrewBase
+class CrewWithMCP:
+  # ... define your agents and tasks config file ...
+
+  mcp_server_params = [
+    # Streamable HTTP Server
+    {
+        "url": "http://localhost:8001/mcp",
+        "transport": "streamable-http"
+    },
+    # SSE Server
+    {
+        "url": "http://localhost:8000/sse",
+        "transport": "sse"
+    },
+    # StdIO Server
+    StdioServerParameters(
+        command="python3",
+        args=["servers/your_stdio_server.py"],
+        env={"UV_PYTHON": "3.12", **os.environ},
+    )
+  ]
+
+  @agent
+  def your_agent(self):
+      return Agent(config=self.agents_config["your_agent"], tools=self.get_mcp_tools()) # you can filter which tool are available also
+
+    # ... rest of your crew setup ...
+```
 ## Explore MCP Integrations
 
 <CardGroup cols={2}>

src/crewai/project/crew_base.py

@@ -1,7 +1,8 @@
 import inspect
 import logging
 from pathlib import Path
-from typing import Any, Callable, Dict, TypeVar, cast
+from typing import Any, Callable, Dict, TypeVar, cast, List
+from crewai.tools import BaseTool
 
 import yaml
 from dotenv import load_dotenv
@@ -27,6 +28,8 @@ def CrewBase(cls: T) -> T:
         )
         original_tasks_config_path = getattr(cls, "tasks_config", "config/tasks.yaml")
 
+        mcp_server_params: Any = getattr(cls, "mcp_server_params", None)
+
         def __init__(self, *args, **kwargs):
             super().__init__(*args, **kwargs)
             self.load_configurations()
@@ -64,6 +67,39 @@ def CrewBase(cls: T) -> T:
                 self._original_functions, "is_kickoff"
             )
 
+            # Add close mcp server method to after kickoff
+            bound_method = self._create_close_mcp_server_method()
+            self._after_kickoff['_close_mcp_server'] = bound_method
+
+        def _create_close_mcp_server_method(self):
+            def _close_mcp_server(self, instance, outputs):
+                adapter = getattr(self, '_mcp_server_adapter', None)
+                if adapter is not None:
+                    try:
+                        adapter.stop()
+                    except Exception as e:
+                        logging.warning(f"Error stopping MCP server: {e}")
+                return outputs
+
+            _close_mcp_server.is_after_kickoff = True
+
+            import types
+            return types.MethodType(_close_mcp_server, self)
+
+        def get_mcp_tools(self) -> List[BaseTool]:
+            if not self.mcp_server_params:
+                return []
+
+            from crewai_tools import MCPServerAdapter
+
+            adapter = getattr(self, '_mcp_server_adapter', None)
+            if adapter and isinstance(adapter, MCPServerAdapter):
+                return adapter.tools
+
+            self._mcp_server_adapter = MCPServerAdapter(self.mcp_server_params)
+            return self._mcp_server_adapter.tools
+
+
         def load_configurations(self):
             """Load agent and task configurations from YAML files."""
             if isinstance(self.original_agents_config_path, str):

tests/project_test.py

@@ -1,5 +1,5 @@
 from typing import List
-
+from unittest.mock import Mock, patch
 import pytest
 
 from crewai.agent import Agent
@@ -16,7 +16,7 @@ from crewai.project import (
     task,
 )
 from crewai.task import Task
-
+from crewai.tools import tool
 
 class SimpleCrew:
     @agent
@@ -85,6 +85,14 @@ class InternalCrew:
     def crew(self):
         return Crew(agents=self.agents, tasks=self.tasks, verbose=True)
 
+@CrewBase
+class InternalCrewWithMCP(InternalCrew):
+    mcp_server_params = {"host": "localhost", "port": 8000}
+
+    @agent
+    def reporting_analyst(self):
+        return Agent(config=self.agents_config["reporting_analyst"], tools=self.get_mcp_tools())  # type: ignore[index]
+
 
 def test_agent_memoization():
     crew = SimpleCrew()
@@ -237,3 +245,17 @@ def test_multiple_before_after_kickoff():
 def test_crew_name():
     crew = InternalCrew()
     assert crew._crew_name == "InternalCrew"
+
+@tool
+def simple_tool():
+    """Return 'Hi!'"""
+    return "Hi!"
+
+def test_internal_crew_with_mcp():
+    mock = Mock()
+    mock.tools = [simple_tool]
+    with patch("crewai_tools.MCPServerAdapter", return_value=mock) as adapter_mock:
+        crew = InternalCrewWithMCP()
+        assert crew.reporting_analyst().tools == [simple_tool]
+
+    adapter_mock.assert_called_once_with({"host": "localhost", "port": 8000})