feat: support user labels in RunConfig

Allow callers to supply custom user labels via RunConfig to propagate billing and attribution labels down to LlmRequest and Vertex API requests.

Co-authored-by: Shangjie Chen <deanchen@google.com>
PiperOrigin-RevId: 952960713

src/google/adk/agents/run_config.py

@@ -199,6 +199,9 @@ class RunConfig(BaseModel):
   http_options: Optional[types.HttpOptions] = None
   """HTTP options for the agent execution (e.g. custom headers)."""
 
+  labels: Optional[dict[str, str]] = None
+  """User labels for the current invocation (e.g. for billing/attribution)."""
+
   response_modalities: Optional[list[types.Modality]] = None
   """The output modalities. If not set, it's default to AUDIO."""
 

src/google/adk/flows/llm_flows/basic.py

@@ -81,6 +81,13 @@ def _build_basic_request(
 
   if run_config_http_options:
     _merge_run_config_http_options(llm_request.config, run_config_http_options)
+
+  # Merge per-invocation user labels from RunConfig into the request config
+  # (e.g. for billing, telemetry, and revenue attribution across services).
+  if invocation_context.run_config and invocation_context.run_config.labels:
+    if llm_request.config.labels is None:
+      llm_request.config.labels = {}
+    llm_request.config.labels.update(invocation_context.run_config.labels)
   # Only set output_schema if no tools are specified. as of now, model don't
   # support output_schema and tools together. we have a workaround to support
   # both output_schema and tools at the same time. see

tests/unittests/flows/llm_flows/test_basic_processor.py

@@ -373,3 +373,29 @@ class TestBasicLlmRequestProcessor:
     assert (
         llm_request.config.http_options.headers['Agent-Header'] == 'agent-val'
     )
+
+  @pytest.mark.asyncio
+  async def test_merges_run_config_labels(self):
+    """RunConfig labels are merged into llm_request.config.labels."""
+    agent = LlmAgent(
+        name='test_agent',
+        model='gemini-1.5-flash',
+        generate_content_config=types.GenerateContentConfig(
+            labels={'agent_label': 'val1'}
+        ),
+    )
+
+    invocation_context = await _create_invocation_context(agent)
+    invocation_context.run_config = RunConfig(
+        labels={'goog-originating-logical-product-id': 'prod1'}
+    )
+    llm_request = LlmRequest()
+
+    processor = _BasicLlmRequestProcessor()
+    async for _ in processor.run_async(invocation_context, llm_request):
+      pass
+
+    assert llm_request.config.labels == {
+        'agent_label': 'val1',
+        'goog-originating-logical-product-id': 'prod1',
+    }