feat(config): implement config and from_config for MCPToolset

The connection_params argument in the constructor is split into four arguments in the config class because some of them have identical fields. In order to identify which is which, a separate name is more convenient.

PiperOrigin-RevId: 791965995

Author: wuliang229

src/google/adk/tools/__init__.py

@@ -11,7 +11,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+import logging
+import sys
 
 from ..auth.auth_tool import AuthToolArguments
 from .agent_tool import AgentTool
@@ -52,3 +53,17 @@
     'ToolContext',
     'transfer_to_agent',
 ]
+
+
+if sys.version_info < (3, 10):
+  logger = logging.getLogger('google_adk.' + __name__)
+  logger.warning(
+      'MCP requires Python 3.10 or above. Please upgrade your Python'
+      ' version in order to use it.'
+  )
+else:
+  from .mcp_tool.mcp_toolset import MCPToolset
+
+  __all__.extend([
+      'MCPToolset',
+  ])

src/google/adk/tools/mcp_tool/mcp_toolset.py

@@ -21,12 +21,17 @@
 from typing import TextIO
 from typing import Union
 
+from pydantic import model_validator
+from typing_extensions import override
+
 from ...agents.readonly_context import ReadonlyContext
 from ...auth.auth_credential import AuthCredential
 from ...auth.auth_schemes import AuthScheme
 from ..base_tool import BaseTool
 from ..base_toolset import BaseToolset
 from ..base_toolset import ToolPredicate
+from ..tool_configs import BaseToolConfig
+from ..tool_configs import ToolArgsConfig
 from .mcp_session_manager import MCPSessionManager
 from .mcp_session_manager import retry_on_closed_resource
 from .mcp_session_manager import SseConnectionParams
@@ -178,3 +183,67 @@ async def close(self) -> None:
     except Exception as e:
       # Log the error but don't re-raise to avoid blocking shutdown
       print(f"Warning: Error during MCPToolset cleanup: {e}", file=self._errlog)
+
+  @override
+  @classmethod
+  def from_config(
+      cls: type[MCPToolset], config: ToolArgsConfig, config_abs_path: str
+  ) -> MCPToolset:
+    """Creates an MCPToolset from a configuration object."""
+    mcp_toolset_config = MCPToolsetConfig.model_validate(config.model_dump())
+
+    if mcp_toolset_config.stdio_server_params:
+      connection_params = mcp_toolset_config.stdio_server_params
+    elif mcp_toolset_config.stdio_connection_params:
+      connection_params = mcp_toolset_config.stdio_connection_params
+    elif mcp_toolset_config.sse_connection_params:
+      connection_params = mcp_toolset_config.sse_connection_params
+    elif mcp_toolset_config.streamable_http_connection_params:
+      connection_params = mcp_toolset_config.streamable_http_connection_params
+    else:
+      raise ValueError("No connection params found in MCPToolsetConfig.")
+
+    return cls(
+        connection_params=connection_params,
+        tool_filter=mcp_toolset_config.tool_filter,
+        auth_scheme=mcp_toolset_config.auth_scheme,
+        auth_credential=mcp_toolset_config.auth_credential,
+    )
+
+
+class MCPToolsetConfig(BaseToolConfig):
+  """The config for MCPToolset."""
+
+  stdio_server_params: Optional[StdioServerParameters] = None
+
+  stdio_connection_params: Optional[StdioConnectionParams] = None
+
+  sse_connection_params: Optional[SseConnectionParams] = None
+
+  streamable_http_connection_params: Optional[
+      StreamableHTTPConnectionParams
+  ] = None
+
+  tool_filter: Optional[List[str]] = None
+
+  auth_scheme: Optional[AuthScheme] = None
+
+  auth_credential: Optional[AuthCredential] = None
+
+  @model_validator(mode="after")
+  def _check_only_one_params_field(self):
+    param_fields = [
+        self.stdio_server_params,
+        self.stdio_connection_params,
+        self.sse_connection_params,
+        self.streamable_http_connection_params,
+    ]
+    populated_fields = [f for f in param_fields if f is not None]
+
+    if len(populated_fields) != 1:
+      raise ValueError(
+          "Exactly one of stdio_server_params, stdio_connection_params,"
+          " sse_connection_params, streamable_http_connection_params must be"
+          " set."
+      )
+    return self