fix: prevent crash when parsing default values for typing.Any parameters

PiperOrigin-RevId: 941154780

Author: google-genai-bot

src/google/adk/tools/_function_parameter_parse_util.py

@@ -222,6 +222,8 @@ def _is_default_value_compatible(
     default_value: Any, annotation: inspect.Parameter.annotation
 ) -> bool:
   # None type is expected to be handled external to this function
+  if annotation is Any:
+    return True
   if _is_builtin_primitive_or_compound(annotation):
     return isinstance(default_value, annotation)
 

tests/unittests/tools/test_from_function_with_options.py

@@ -519,3 +519,19 @@ def generate_image(
   assert array_schema.items.items.any_of[0].type == types.Type.STRING
   assert array_schema.items.items.any_of[0].format is None
   assert array_schema.items.items.any_of[1].type == types.Type.STRING
+
+
+def test_from_function_with_options_any_type_with_default_value():
+  """Test that typing.Any with a default value works and doesn't crash."""
+
+  def my_tool(param: Any = 'default_string') -> str:
+    return f'ok {param}'
+
+  declaration = _automatic_function_calling_util.from_function_with_options(
+      my_tool, GoogleLLMVariant.GEMINI_API
+  )
+
+  assert declaration.parameters is not None
+  assert declaration.parameters.properties['param'].default == 'default_string'
+  # Any type maps to None (no type) in schema
+  assert declaration.parameters.properties['param'].type is None