AI-60: Add summary_fn parameter to TemporalModel for dynamic activity summaries (#1451)

* AI-60: Add AdkActivityConfig with summary_fn for dynamic activity summaries

Introduce AdkActivityConfig extending ActivityConfig with a summary_fn
field that accepts a callable for dynamic per-call summaries. When no
summary_fn or static summary is set, falls back to reading adk_agent_name
from LlmRequest labels for zero-config agent name display.

Setting both summary and summary_fn raises ValueError to prevent ambiguity.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* AI-60: Address auditor findings — determinism note, summary_fn None test, label fallback test

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* AI-60: Switch to summary_fn keyword param, address auditor findings

Drop AdkActivityConfig in favor of a keyword-only summary_fn parameter
on TemporalModel. Zero type: ignore comments needed.

Auditor findings addressed:
- Label fallback test rewritten as integration test
- Exception propagation documented in summary_fn docstring
- Empty string summary test added

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* AI-60: Qualify 'summary' as ActivityConfig summary in error message and docstring

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* AI-60: Consolidate summary tests into single workflow run

Run all 4 summary_fn variants (dynamic, None, empty, label fallback)
as sequential agent invocations within one workflow, reducing CI overhead.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: xumaple

temporalio/contrib/google_adk_agents/_model.py

@@ -1,4 +1,4 @@
-from collections.abc import AsyncGenerator
+from collections.abc import AsyncGenerator, Callable
 from datetime import timedelta
 
 from google.adk.models import BaseLlm, LLMRegistry
@@ -40,20 +40,37 @@ class TemporalModel(BaseLlm):
     """A Temporal-based LLM model that executes model invocations as activities."""
 
     def __init__(
-        self, model_name: str, activity_config: ActivityConfig | None = None
+        self,
+        model_name: str,
+        activity_config: ActivityConfig | None = None,
+        *,
+        summary_fn: Callable[[LlmRequest], str | None] | None = None,
     ) -> None:
         """Initialize the TemporalModel.
 
         Args:
             model_name: The name of the model to use.
             activity_config: Configuration options for the activity execution.
+            summary_fn: Optional callable that receives the LlmRequest and
+                returns a summary string (or None) for the activity. Must be
+                deterministic as it is called during workflow execution. If
+                the callable raises, the exception will propagate and fail
+                the workflow task.
+
+        Raises:
+            ValueError: If both ``ActivityConfig["summary"]`` and ``summary_fn`` are set.
         """
         super().__init__(model=model_name)
         self._model_name = model_name
+        self._summary_fn = summary_fn
         self._activity_config = ActivityConfig(
             start_to_close_timeout=timedelta(seconds=60)
         )
-        if activity_config:
+        if activity_config is not None:
+            if summary_fn is not None and activity_config.get("summary") is not None:
+                raise ValueError(
+                    "Cannot specify both ActivityConfig 'summary' and 'summary_fn'"
+                )
             self._activity_config.update(activity_config)
 
     async def generate_content_async(
@@ -76,10 +93,20 @@ async def generate_content_async(
                 yield response
             return
 
+        config = self._activity_config.copy()
+        if self._summary_fn is not None:
+            summary = self._summary_fn(llm_request)
+            if summary is not None:
+                config["summary"] = summary
+        elif "summary" not in config:
+            if llm_request.config and llm_request.config.labels:
+                agent_name = llm_request.config.labels.get("adk_agent_name")
+                if agent_name:
+                    config["summary"] = agent_name
         responses = await workflow.execute_activity(
             invoke_model,
             args=[llm_request],
-            **self._activity_config,
+            **config,
         )
         for response in responses:
             yield response

tests/contrib/google_adk_agents/test_google_adk_agents.py

@@ -580,6 +580,103 @@ async def test_unsetting_timeout():
     assert model._activity_config.get("start_to_close_timeout", None) is None
 
 
+class SummaryFnModel(TestModel):
+    """Returns a single text response for summary_fn testing."""
+
+    def responses(self) -> list[LlmResponse]:
+        return [
+            LlmResponse(content=Content(role="model", parts=[Part(text="response")])),
+        ]
+
+    @classmethod
+    def supported_models(cls) -> list[str]:
+        return ["summary_fn_model"]
+
+
+@workflow.defn
+class SummaryTestWorkflow:
+    @workflow.run
+    async def run(self, model_name: str) -> None:
+        modes = [
+            ("dynamic", lambda req: f"Invoking {req.model}"),
+            ("none", lambda req: None),
+            ("empty", lambda req: ""),
+            ("label_fallback", None),
+        ]
+        for mode_name, summary_fn in modes:
+            agent = Agent(
+                name=f"summary_test_{mode_name}",
+                model=TemporalModel(model_name, summary_fn=summary_fn),
+            )
+            runner = InMemoryRunner(agent=agent, app_name=f"summary_{mode_name}")
+            session = await runner.session_service.create_session(
+                app_name=f"summary_{mode_name}", user_id="test"
+            )
+            async with Aclosing(
+                runner.run_async(
+                    user_id="test",
+                    session_id=session.id,
+                    new_message=types.Content(
+                        role="user", parts=[types.Part(text="hi")]
+                    ),
+                )
+            ) as agen:
+                async for _ in agen:
+                    pass
+
+
+@pytest.mark.asyncio
+async def test_summary_fn_variants(client: Client):
+    """Test summary_fn with dynamic, None, empty string, and label fallback."""
+    new_config = client.config()
+    new_config["plugins"] = [GoogleAdkPlugin()]
+    client = Client(**new_config)
+    LLMRegistry.register(SummaryFnModel)
+
+    async with Worker(
+        client,
+        task_queue="adk-summary-test",
+        workflows=[SummaryTestWorkflow],
+        max_cached_workflows=0,
+    ):
+        handle = await client.start_workflow(
+            SummaryTestWorkflow.run,
+            "summary_fn_model",
+            id=f"summary-test-{uuid.uuid4()}",
+            task_queue="adk-summary-test",
+            execution_timeout=timedelta(seconds=60),
+        )
+        await handle.result()
+
+        summaries = []
+        async for e in handle.fetch_history_events():
+            if e.HasField("activity_task_scheduled_event_attributes"):
+                attrs = e.activity_task_scheduled_event_attributes
+                if attrs.activity_type.name == "invoke_model":
+                    summaries.append(e.user_metadata.summary.data)
+
+        assert len(summaries) == 4
+        assert summaries[0] == b'"Invoking summary_fn_model"'  # dynamic
+        assert summaries[1] == b""  # none
+        assert summaries[2] == b""  # empty
+        assert (
+            summaries[3] == b'"summary_test_label_fallback"'
+        )  # label fallback agent name
+
+
+def test_summary_and_summary_fn_raises():
+    """Cannot specify both summary and summary_fn."""
+    with pytest.raises(
+        ValueError,
+        match="Cannot specify both ActivityConfig 'summary' and 'summary_fn'",
+    ):
+        TemporalModel(
+            "m",
+            activity_config=ActivityConfig(summary="static"),
+            summary_fn=lambda req: "dynamic",
+        )
+
+
 @pytest.mark.asyncio
 async def test_agent_outside_workflow():
     """Test that an agent using TemporalModel and activity_tool works outside a Temporal workflow."""