feat: Introduce custom_metadata field to run_config and propagate a2a request metadata to that field

PiperOrigin-RevId: 823066539

src/google/adk/a2a/converters/request_converter.py

@@ -106,6 +106,10 @@ def convert_a2a_request_to_agent_run_request(
   if not request.message:
     raise ValueError('Request message cannot be None')
 
+  custom_metadata = {}
+  if request.metadata:
+    custom_metadata['a2a_metadata'] = request.metadata
+
   return AgentRunRequest(
       user_id=_get_user_id(request),
       session_id=request.context_id,
@@ -113,5 +117,5 @@ def convert_a2a_request_to_agent_run_request(
           role='user',
           parts=[part_converter(part) for part in request.message.parts],
       ),
-      run_config=RunConfig(),
+      run_config=RunConfig(custom_metadata=custom_metadata),
   )

src/google/adk/agents/run_config.py

@@ -17,6 +17,7 @@ from __future__ import annotations
 from enum import Enum
 import logging
 import sys
+from typing import Any
 from typing import Optional
 
 from google.genai import types
@@ -118,6 +119,9 @@ class RunConfig(BaseModel):
     - Less than or equal to 0: This allows for unbounded number of llm calls.
   """
 
+  custom_metadata: Optional[dict[str, Any]] = None
+  """Custom metadata for the current invocation."""
+
   @field_validator('max_llm_calls', mode='after')
   @classmethod
   def validate_max_llm_calls(cls, value: int) -> int:

tests/unittests/a2a/converters/test_request_converter.py

@@ -165,6 +165,7 @@ class TestConvertA2aRequestToAgentRunRequest:
     request.message = mock_message
     request.context_id = "test_context_123"
     request.call_context = mock_call_context
+    request.metadata = {"test_key": "test_value"}
 
     # Create proper genai_types.Part objects instead of mocks
     mock_genai_part1 = genai_types.Part(text="test part 1")
@@ -185,6 +186,9 @@ class TestConvertA2aRequestToAgentRunRequest:
     assert result.new_message.role == "user"
     assert result.new_message.parts == [mock_genai_part1, mock_genai_part2]
     assert isinstance(result.run_config, RunConfig)
+    assert result.run_config.custom_metadata == {
+        "a2a_metadata": {"test_key": "test_value"}
+    }
 
     # Verify calls
     assert mock_convert_part.call_count == 2
@@ -212,6 +216,7 @@ class TestConvertA2aRequestToAgentRunRequest:
     request.message = mock_message
     request.context_id = "test_context_123"
     request.call_context = None
+    request.metadata = {}
 
     # Act
     result = convert_a2a_request_to_agent_run_request(
@@ -241,6 +246,7 @@ class TestConvertA2aRequestToAgentRunRequest:
     request.message = mock_message
     request.context_id = None
     request.call_context = None
+    request.metadata = {}
 
     # Create proper genai_types.Part object instead of mock
     mock_genai_part = genai_types.Part(text="test part")
@@ -272,6 +278,7 @@ class TestConvertA2aRequestToAgentRunRequest:
     request.message = mock_message
     request.context_id = "session_123"
     request.call_context = None
+    request.metadata = {}
 
     # Create proper genai_types.Part object instead of mock
     mock_genai_part = genai_types.Part(text="test part")
@@ -313,6 +320,7 @@ class TestIntegration:
     request.call_context = mock_call_context
     request.message = mock_message
     request.context_id = "mysession"
+    request.metadata = {}
 
     # Create proper genai_types.Part object instead of mock
     mock_genai_part = genai_types.Part(text="test part")
@@ -344,6 +352,7 @@ class TestIntegration:
     request.call_context = None
     request.message = mock_message
     request.context_id = "test_session_456"
+    request.metadata = {}
 
     # Create proper genai_types.Part object instead of mock
     mock_genai_part = genai_types.Part(text="test part")