feat: expose credential service in readonly context

src/google/adk/agents/readonly_context.py

@@ -23,6 +23,7 @@ if TYPE_CHECKING:
   from google.genai import types
 
   from .invocation_context import InvocationContext
+  from ..auth.credential_service.base_credential_service import BaseCredentialService
 
 
 class ReadonlyContext:
@@ -52,3 +53,8 @@ class ReadonlyContext:
   def state(self) -> MappingProxyType[str, Any]:
     """The state of the current session. READONLY field."""
     return MappingProxyType(self._invocation_context.session.state)
+
+  @property
+  def credential_service(self) -> Optional[BaseCredentialService]:
+    """The credential service for the current invocation."""
+    return self._invocation_context.credential_service

src/google/adk/tools/agent_tool.py

@@ -116,6 +116,7 @@ class AgentTool(BaseTool):
         artifact_service=ForwardingArtifactService(tool_context),
         session_service=InMemorySessionService(),
         memory_service=InMemoryMemoryService(),
+        credential_service=tool_context.credential_service,
     )
     session = await runner.session_service.create_session(
         app_name=self.agent.name,

tests/unittests/agents/test_readonly_context.py

@@ -2,15 +2,25 @@ from types import MappingProxyType
 from unittest.mock import MagicMock
 
 from google.adk.agents.readonly_context import ReadonlyContext
+from google.adk.auth.credential_service.base_credential_service import BaseCredentialService
 import pytest
 
 
+class DummyCredentialService(BaseCredentialService):
+  async def load_credential(self,auth_config, tool_context):
+    pass
+
+  async def save_credential(self,auth_config, tool_context):
+    pass
+
+
 @pytest.fixture
 def mock_invocation_context():
   mock_context = MagicMock()
   mock_context.invocation_id = "test-invocation-id"
   mock_context.agent.name = "test-agent-name"
   mock_context.session.state = {"key1": "value1", "key2": "value2"}
+  mock_context.credential_service = DummyCredentialService()
 
   return mock_context
 
@@ -32,3 +42,9 @@ def test_state_content(mock_invocation_context):
   assert isinstance(state, MappingProxyType)
   assert state["key1"] == "value1"
   assert state["key2"] == "value2"
+
+
+def test_credential_service(mock_invocation_context):
+  readonly_context = ReadonlyContext(mock_invocation_context)
+  assert readonly_context.credential_service is not None
+  assert isinstance(readonly_context.credential_service, BaseCredentialService)