diff --git a/src/google/adk/tools/_function_tool_declarations.py b/src/google/adk/tools/_function_tool_declarations.py
index ebb6af7de5..f766c8245b 100644
--- a/src/google/adk/tools/_function_tool_declarations.py
+++ b/src/google/adk/tools/_function_tool_declarations.py
@@ -40,6 +40,7 @@
 from pydantic import create_model
 from pydantic import fields as pydantic_fields
 
+from ..utils._callable_utils import unwrap_callable
 from ..utils.variant_utils import get_google_llm_variant
 from ..utils.variant_utils import GoogleLLMVariant
 
@@ -66,7 +67,7 @@ def _get_function_fields(
 
   # Get type hints with forward reference resolution
   try:
-    type_hints = get_type_hints(func)
+    type_hints = get_type_hints(unwrap_callable(func))
   except TypeError:
     # Can happen with mock objects or complex annotations
     type_hints = {}
@@ -234,7 +235,7 @@ def _build_response_json_schema(
   # Handle string annotations (forward references)
   if isinstance(return_annotation, str):
     try:
-      type_hints = get_type_hints(func)
+      type_hints = get_type_hints(unwrap_callable(func))
       return_annotation = type_hints.get('return', return_annotation)
     except TypeError:
       pass
@@ -264,7 +265,7 @@ def _build_response_json_schema(
       logging.debug(
           'Failed to build schema with config, retrying without config for'
           ' %s: %s',
-          func.__name__,
+          get_callable_name(func),
           e,
       )
       adapter = pydantic.TypeAdapter(return_annotation)
@@ -272,7 +273,7 @@ def _build_response_json_schema(
   except Exception:
     logging.warning(
         'Failed to build response JSON schema for %s',
-        func.__name__,
+        get_callable_name(func),
         exc_info=True,
     )
     # Fall back to untyped response
diff --git a/tests/unittests/tools/test_function_tool_with_import_annotations.py b/tests/unittests/tools/test_function_tool_with_import_annotations.py
index c917bc2ca6..2fae009905 100644
--- a/tests/unittests/tools/test_function_tool_with_import_annotations.py
+++ b/tests/unittests/tools/test_function_tool_with_import_annotations.py
@@ -14,6 +14,7 @@
 
 from __future__ import annotations
 
+import functools
 from typing import Any
 from typing import Dict
 from typing import Optional
@@ -23,6 +24,7 @@
 from google.adk.utils.variant_utils import GoogleLLMVariant
 from google.genai import types
 import pydantic
+import pytest
 
 
 def test_string_annotation_none_return_vertex():
@@ -207,6 +209,33 @@ class ItemModel(pydantic.BaseModel):
   quantity: int
 
 
+@pytest.mark.parametrize('wrapper', ['function', 'partial', 'callable'])
+def test_wrapped_tool_resolves_model_annotations(wrapper):
+  """Wrapped tools advertise the same resolved input and output model types."""
+
+  def lookup(prefix: str, item: ItemModel) -> ItemModel:
+    return item
+
+  class Lookup:
+
+    def __call__(self, item: ItemModel) -> ItemModel:
+      return item
+
+  functions = {
+      'function': lookup,
+      'partial': functools.partial(lookup, 'catalog'),
+      'callable': Lookup(),
+  }
+  declaration = _automatic_function_calling_util.build_function_declaration(
+      functions[wrapper], variant=GoogleLLMVariant.VERTEX_AI
+  )
+
+  schema = declaration.parameters_json_schema
+  assert schema['properties']['item']['$ref'] == '#/$defs/ItemModel'
+  assert schema['$defs']['ItemModel'] == ItemModel.model_json_schema()
+  assert declaration.response_json_schema == ItemModel.model_json_schema()
+
+
 def test_preprocess_args_with_list_of_pydantic_models_and_annotations():
   """Test _preprocess_args converts dict to Pydantic model with string annotations."""