mypy fix

Author: rectalogic

.github/workflows/test.yml

@@ -29,4 +29,8 @@ jobs:
       run: |
         uv run --python ${{ matrix.python-version }} --python-preference only-system ruff format --check
         uv run --python ${{ matrix.python-version }} --python-preference only-system ruff check
+    - name: Mypy
+      # Disable until fix released https://github.com/pydantic/pydantic/pull/10979
+      if: ${{ matrix.python-version != '3.13' }}
+      run: |
         uv run --python ${{ matrix.python-version }} --python-preference only-system mypy 

src/langchain_mcp/toolkit.py

@@ -68,7 +68,6 @@ class MCPTool(BaseTool):
     """
 
     session: ClientSession
-    args_schema: type[pydantic.BaseModel]
     handle_tool_error: bool | str | Callable[[ToolException], str] | None = True
 
     @t.override
@@ -89,4 +88,5 @@ async def _arun(self, *args: t.Any, **kwargs: t.Any) -> t.Any:
     @t.override
     @property
     def tool_call_schema(self) -> type[pydantic.BaseModel]:
+        assert self.args_schema is not None  # noqa: S101
         return self.args_schema