Stop pydantic 2.13 from leaking _WrappedResult docstring into tool output schemas (#3918)

Author: jlowin

.github/workflows/run-upgrade-checks.yml

@@ -121,7 +121,7 @@ jobs:
 
             - **ty (type checker)**: New ty releases frequently add stricter checks that flag previously-accepted code. Run `uv run ty check` locally with the latest ty to reproduce. Fix the type errors or bump the ty version floor in `pyproject.toml`.
             - **ruff**: New lint rules or stricter defaults in a ruff upgrade.
-            - **mcp SDK**: Breaking changes in the `mcp` package (new method signatures, renamed types).
+            - **MCP SDK**: Breaking changes in the `mcp` package (new method signatures, renamed types).
 
             ### What to do
 

src/fastmcp/tools/function_parsing.py

@@ -67,8 +67,6 @@ def _contains_prefab_type(tp: Any) -> bool:
 
 @dataclass
 class _WrappedResult(Generic[T]):
-    """Generic wrapper for non-object return types."""
-
     result: T