Python: [BREAKING] Remove FunctionTool[Any] compatibility shim for schema passthrough (#3600) (#3907)

* Fix #3600: Pass JSON schemas through without Pydantic conversion

This change optimizes FunctionTool and MCP flows by passing JSON schemas
directly to providers without converting them to Pydantic models first.

Key changes:
- Store JSON schema as-is when supplied to FunctionTool
- Skip Pydantic model_validate for schema-supplied tools in invoke()
- Return MCP tool schemas directly without conversion
- Add comprehensive tests for schema passthrough behavior

Performance benefits:
- Eliminates expensive Pydantic model creation for supplied schemas
- Preserves exact schema structure (additionalProperties, custom fields, etc.)
- Reduces memory overhead and initialization time

Maintains backward compatibility:
- Function signature inference still uses Pydantic models
- Explicit Pydantic models passed as input_model work as before
- All existing tests pass

* Fix schema passthrough validation and remove helper

* Simplify FunctionTool without generic model dependency

* Fix FunctionTool typing fallout in 3600

* Remove FunctionTool[Any] compatibility shim

* Use serializable kwargs in OTEL tool args

python/packages/ag-ui/agent_framework_ag_ui/_client.py

@@ -267,7 +267,7 @@ class AGUIChatClient(
         if any(getattr(tool, "name", None) == tool_name for tool in additional_tools):
             return
 
-        placeholder: FunctionTool[Any] = FunctionTool(
+        placeholder: FunctionTool = FunctionTool(
             name=tool_name,
             description="Server-managed tool placeholder (AG-UI)",
             func=None,

python/packages/ag-ui/agent_framework_ag_ui/_utils.py

@@ -162,7 +162,7 @@ def make_json_safe(obj: Any) -> Any:  # noqa: ANN401
 
 def convert_agui_tools_to_agent_framework(
     agui_tools: list[dict[str, Any]] | None,
-) -> list[FunctionTool[Any]] | None:
+) -> list[FunctionTool] | None:
     """Convert AG-UI tool definitions to Agent Framework FunctionTool declarations.
 
     Creates declaration-only FunctionTool instances (no executable implementation).
@@ -181,13 +181,13 @@ def convert_agui_tools_to_agent_framework(
     if not agui_tools:
         return None
 
-    result: list[FunctionTool[Any]] = []
+    result: list[FunctionTool] = []
     for tool_def in agui_tools:
         # Create declaration-only FunctionTool (func=None means no implementation)
         # When func=None, the declaration_only property returns True,
         # which tells the function invocation mixin to return the function call
         # without executing it (so it can be sent back to the client)
-        func: FunctionTool[Any] = FunctionTool(
+        func: FunctionTool = FunctionTool(
             name=tool_def.get("name", ""),
             description=tool_def.get("description", ""),
             func=None,  # CRITICAL: Makes declaration_only=True