feat(tools): resolve built-in tools for managed-agent requests

Add an is_managed_agent flag to LlmRequest so the google_search and url_context
built-in tools resolve their server-side config even when no Gemini model is
set. The flag defaults to False, so existing flows are unchanged.

Co-authored-by: Haran Rajkumar <haranrk@google.com>
PiperOrigin-RevId: 939997610

Author: haranrk

src/google/adk/models/llm_request.py

@@ -22,6 +22,7 @@
 from pydantic import BaseModel
 from pydantic import ConfigDict
 from pydantic import Field
+from pydantic import PrivateAttr
 
 from ..agents.context_cache_config import ContextCacheConfig
 from ..tools.base_tool import BaseTool
@@ -100,6 +101,15 @@ class LlmRequest(BaseModel):
   the full history.
   """
 
+  _is_managed_agent: bool = PrivateAttr(default=False)
+  """Internal flag: whether this request was built by a ManagedAgent.
+
+  This is an internal implementation detail (not part of the serialized request
+  schema). It is set by ``ManagedAgent`` and read only through the
+  ``_is_managed_agent`` helper in ``model_name_utils`` so built-in tools resolve
+  server-side without a Gemini model.
+  """
+
   def append_instructions(
       self, instructions: Union[list[str], types.Content]
   ) -> list[types.Content]:

src/google/adk/tools/google_search_tool.py

@@ -19,6 +19,7 @@
 from google.genai import types
 from typing_extensions import override
 
+from ..utils.model_name_utils import _is_managed_agent
 from ..utils.model_name_utils import is_gemini_1_model
 from ..utils.model_name_utils import is_gemini_model
 from ..utils.model_name_utils import is_gemini_model_id_check_disabled
@@ -79,7 +80,11 @@ async def process_llm_request(
       llm_request.config.tools.append(
           types.Tool(google_search_retrieval=types.GoogleSearchRetrieval())
       )
-    elif is_gemini_model(llm_request.model) or model_check_disabled:
+    elif (
+        is_gemini_model(llm_request.model)
+        or model_check_disabled
+        or _is_managed_agent(llm_request)
+    ):
       llm_request.config.tools.append(
           types.Tool(google_search=types.GoogleSearch())
       )

src/google/adk/tools/url_context_tool.py

@@ -19,6 +19,7 @@
 from google.genai import types
 from typing_extensions import override
 
+from ..utils.model_name_utils import _is_managed_agent
 from ..utils.model_name_utils import is_gemini_1_model
 from ..utils.model_name_utils import is_gemini_eap_or_2_or_above
 from ..utils.model_name_utils import is_gemini_model_id_check_disabled
@@ -52,7 +53,11 @@ async def process_llm_request(
     llm_request.config.tools = llm_request.config.tools or []
     if is_gemini_1_model(llm_request.model):
       raise ValueError('Url context tool cannot be used in Gemini 1.x.')
-    elif is_gemini_eap_or_2_or_above(llm_request.model) or model_check_disabled:
+    elif (
+        is_gemini_eap_or_2_or_above(llm_request.model)
+        or model_check_disabled
+        or _is_managed_agent(llm_request)
+    ):
       llm_request.config.tools.append(
           types.Tool(url_context=types.UrlContext())
       )

src/google/adk/utils/model_name_utils.py

@@ -18,12 +18,16 @@
 
 import re
 from typing import Optional
+from typing import TYPE_CHECKING
 
 from packaging.version import InvalidVersion
 from packaging.version import Version
 
 from .env_utils import is_env_enabled
 
+if TYPE_CHECKING:
+  from ..models.llm_request import LlmRequest
+
 _DISABLE_GEMINI_MODEL_ID_CHECK_ENV_VAR = 'ADK_DISABLE_GEMINI_MODEL_ID_CHECK'
 
 
@@ -36,6 +40,11 @@ def is_gemini_model_id_check_disabled() -> bool:
   return is_env_enabled(_DISABLE_GEMINI_MODEL_ID_CHECK_ENV_VAR)
 
 
+def _is_managed_agent(llm_request: LlmRequest) -> bool:
+  """Whether the request was built by a ManagedAgent."""
+  return llm_request._is_managed_agent
+
+
 def extract_model_name(model_string: str) -> str:
   """Extract the actual model name from either simple or path-based format.
 

tests/unittests/models/test_llm_request.py

@@ -834,3 +834,16 @@ def test_append_instructions_with_only_text_parts():
 
   # Should return empty list since no non-text parts
   assert user_contents == []
+
+
+def test_is_managed_agent_defaults_false():
+  """_is_managed_agent defaults to False for ordinary requests."""
+  request = LlmRequest()
+  assert request._is_managed_agent is False
+
+
+def test_is_managed_agent_can_be_set_true():
+  """_is_managed_agent is an internal flag set after construction."""
+  request = LlmRequest()
+  request._is_managed_agent = True
+  assert request._is_managed_agent is True

tests/unittests/tools/test_google_search_tool.py

@@ -516,3 +516,23 @@ async def test_process_llm_request_custom_model_behavior(
     assert llm_request.model == expected_model
     assert llm_request.config.tools is not None
     assert len(llm_request.config.tools) == 1
+
+  @pytest.mark.asyncio
+  async def test_process_llm_request_managed_agent_no_model(self):
+    """Managed-agent requests resolve google_search even with no model."""
+    tool = GoogleSearchTool()
+    tool_context = await _create_tool_context()
+
+    llm_request = LlmRequest(
+        model=None,
+        config=types.GenerateContentConfig(),
+    )
+    llm_request._is_managed_agent = True
+
+    await tool.process_llm_request(
+        tool_context=tool_context, llm_request=llm_request
+    )
+
+    assert llm_request.config.tools is not None
+    assert len(llm_request.config.tools) == 1
+    assert llm_request.config.tools[0].google_search is not None

tests/unittests/tools/test_url_context_tool.py

@@ -322,3 +322,23 @@ async def test_process_llm_request_edge_cases(self):
         await tool.process_llm_request(
             tool_context=tool_context, llm_request=llm_request
         )
+
+  @pytest.mark.asyncio
+  async def test_process_llm_request_managed_agent_no_model(self):
+    """Managed-agent requests resolve url_context even with no model."""
+    tool = UrlContextTool()
+    tool_context = await _create_tool_context()
+
+    llm_request = LlmRequest(
+        model=None,
+        config=types.GenerateContentConfig(),
+    )
+    llm_request._is_managed_agent = True
+
+    await tool.process_llm_request(
+        tool_context=tool_context, llm_request=llm_request
+    )
+
+    assert llm_request.config.tools is not None
+    assert len(llm_request.config.tools) == 1
+    assert llm_request.config.tools[0].url_context is not None

tests/unittests/utils/test_model_name_utils.py

@@ -14,6 +14,8 @@
 
 """Tests for model name utility functions."""
 
+from google.adk.models.llm_request import LlmRequest
+from google.adk.utils.model_name_utils import _is_managed_agent
 from google.adk.utils.model_name_utils import extract_model_name
 from google.adk.utils.model_name_utils import is_gemini_1_model
 from google.adk.utils.model_name_utils import is_gemini_3_1_flash_live
@@ -429,3 +431,15 @@ def test_is_gemini_3_5_live_translate_edge_cases(self):
     """Test edge cases."""
     assert is_gemini_3_5_live_translate(None) is False
     assert is_gemini_3_5_live_translate('') is False
+
+
+class TestIsManagedAgent:
+  """Tests for the _is_managed_agent predicate."""
+
+  def test_true_when_flag_set(self):
+    request = LlmRequest()
+    request._is_managed_agent = True
+    assert _is_managed_agent(request) is True
+
+  def test_false_by_default(self):
+    assert _is_managed_agent(LlmRequest()) is False