Python: feat: Add Agent Framework to A2A bridge support #2403

Shubham-Kumar-2000 · 2025-11-23T13:40:17Z

Motivation and Context

This integration enables agent framework agents to communicate and execute as a A2A hosted agent server.

Description

Implement A2A event adapter for converting agent messages to A2A protocol
Implement A2A executor for running agents in A2A environment
Add comprehensive unit tests for event adapter, and executor
Update agent framework core A2A module exports and type stubs
Integrate thread management utilities for async execution
Add getting started sample for A2A agent framework integration
Update dependencies in uv.lock

Contribution Checklist

The code builds clean without any errors or warnings
The PR follows the Contribution Guidelines
All unit tests pass, and I have added new tests where possible
Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

- Implement A2A event adapter for converting agent messages to A2A protocol - Add A2A execution context for managing agent execution state - Implement A2A executor for running agents in A2A environment - Add comprehensive unit tests for event adapter, execution context, and executor - Update agent framework core A2A module exports and type stubs - Integrate thread management utilities for async execution - Add getting started sample for A2A agent framework integration - Update dependencies in uv.lock This integration enables agent framework agents to communicate and execute within the A2A (Agent to Agent) infrastructure.

…rage in A2A executor tests

- Reordered imports in various files for consistency and clarity. - Updated `__all__` definitions to maintain a consistent order across modules. - Simplified method signatures by removing unnecessary line breaks. - Enhanced readability by adjusting formatting in several sections. - Removed redundant comments and example scenarios in the execution context. - Improved handling of agent messages in the event adapter. - Added type hints for better clarity and type checking. - Cleaned up test cases for better organization and readability.

…orage

- Deleted the test file for A2aExecutionContext as it is no longer needed. - Updated A2aExecutor tests to remove dependencies on A2aExecutionContext and adjusted method calls accordingly. - Modified event adapter tests to use ChatMessage instead of AgentRunResponseUpdate. - Removed A2aExecutionContext from imports in agent_framework.a2a module and updated type hints accordingly.

eavanvalkenburg

I like the idea behind this, but there are some major issues with the implementation, especially the addition of the AgentThreadStore, please discuss that further with us.

eavanvalkenburg · 2025-11-25T19:19:44Z

python/packages/a2a/agent_framework_a2a/_a2a_event_adapter.py

+from agent_framework import ChatMessage, DataContent, Role, TextContent, UriContent
+
+
+class A2aEventAdapter(ABC):


We use python default styles for things like abbreviations, so:

Suggested change

class A2aEventAdapter(ABC):

class A2AEventAdapter(ABC):

eavanvalkenburg · 2025-11-25T19:20:02Z

python/packages/a2a/agent_framework_a2a/_a2a_event_adapter.py

+        pass
+
+
+class BaseA2aEventAdapter(A2aEventAdapter):


Suggested change

class BaseA2aEventAdapter(A2aEventAdapter):

class BaseA2AEventAdapter(A2aEventAdapter):

eavanvalkenburg · 2025-11-25T19:20:50Z

python/packages/a2a/agent_framework_a2a/_a2a_event_adapter.py

+            if isinstance(content, TextContent):
+                parts.append(Part(root=TextPart(text=content.text)))
+            if isinstance(content, DataContent):
+                parts.append(Part(root=FilePart(file=FileWithBytes(bytes=_extract_base64_from_uri(content.uri)))))


there is a method on DataContent for this:

Suggested change

parts.append(Part(root=FilePart(file=FileWithBytes(bytes=_extract_base64_from_uri(content.uri)))))

parts.append(Part(root=FilePart(file=FileWithBytes(bytes=content.get_data_bytes())))

(there is also a get_data_bytes_as_str in case the data type needs to be the string representation

eavanvalkenburg · 2025-11-25T19:21:15Z

python/packages/a2a/agent_framework_a2a/_a2a_event_adapter.py

+                # Handle URI content
+                parts.append(
+                    Part(
+                        root=FilePart(file=FileWithUri(uri=content.uri, mime_type=getattr(content, "media_type", None)))


no need for getattr, UriContent always has media_type as a attribute.

Suggested change

root=FilePart(file=FileWithUri(uri=content.uri, mime_type=getattr(content, "media_type", None)))

root=FilePart(file=FileWithUri(uri=content.uri, mime_type=content.media_type))

eavanvalkenburg · 2025-11-25T19:23:06Z

python/packages/a2a/agent_framework_a2a/_a2a_event_adapter.py

+            )
+
+
+def _extract_base64_from_uri(uri: str) -> str:


remove this

eavanvalkenburg · 2025-11-25T19:23:27Z

python/packages/a2a/agent_framework_a2a/_a2a_executor.py

+from ._a2a_event_adapter import A2aEventAdapter, BaseA2aEventAdapter
+
+
+class A2aExecutor(AgentExecutor):


Same as before:

Suggested change

class A2aExecutor(AgentExecutor):

class A2AExecutor(AgentExecutor):

eavanvalkenburg · 2025-11-25T19:24:13Z

python/packages/a2a/agent_framework_a2a/_a2a_event_adapter.py

+        Example:
+            Demonstrating the internal processing:
+
+            ```python


make sure code comments are marked appropriately, with .. code-block:: python. This applies in a number of places.

eavanvalkenburg · 2025-11-25T19:25:17Z

python/packages/a2a/agent_framework_a2a/_a2a_event_adapter.py

+from agent_framework import ChatMessage, DataContent, Role, TextContent, UriContent
+
+
+class A2aEventAdapter(ABC):


Do we even need this base class? Since the base class also has this single method, it doesn't add anything.

eavanvalkenburg · 2025-11-25T19:27:41Z

python/packages/core/agent_framework/_threads.py

        self.message_store = ChatMessageStore(messages=state.chat_message_store_state.messages, **kwargs)
+
+
+class AgentThreadStorage(ABC):


why are you adding this, we already have multiple ways of dealing with threads. Including serializing and deserializing them. So please don't add completely new concepts in the core package without first creating an issue and discussing the needs.

eavanvalkenburg · 2025-11-25T19:29:21Z

python/packages/a2a/agent_framework_a2a/_a2a_executor.py

+        self._agent: ChatAgent | WorkflowAgent = agent
+        self._event_adapter: A2aEventAdapter = event_adapter if event_adapter else BaseA2aEventAdapter()
+
+    async def cancel(self, context: RequestContext, event_queue: EventQueue) -> None:


please add the @overload decorator so that it's clear which method come from the AgentExecutor.

- Updated test cases to use A2AExecutor instead of A2aExecutor for consistency. - Removed mock_event_adapter fixture and related tests as A2aEventAdapter is deprecated. - Consolidated event handling tests into TestA2AExecutorEventAdapter. - Adjusted imports in various files to reflect the removal of deprecated components. - Ensured all references to A2aExecutor are updated to A2AExecutor across the codebase.

Shubham-Kumar-2000 · 2025-11-25T21:56:37Z

Hi @eavanvalkenburg thanks for the review.

I have further simplified the code for this feature and have addressed most of you review comments.

Regarding your major concern around AgentThreadStore I have started a discussion to finalize the approach.
#2463

Do let me know if any other changes are required.

markwallace-microsoft added documentation Improvements or additions to documentation python labels Nov 23, 2025

github-actions bot changed the title ~~feat: Add Agent Framework to A2A bridge support~~ Python: feat: Add Agent Framework to A2A bridge support Nov 23, 2025

Shubham-Kumar-2000 added 7 commits November 23, 2025 19:19

fix: Update references from agent_thread_storage to _agent_thread_sto…

828b733

…rage in A2A executor tests

fix: Lint fix new line added

1e600dc

test: Add unit tests for AgentThreadStorage and InMemoryAgentThreadSt…

c7a8b80

…orage

refactor: Update type hints to use new syntax for Union and List

db5bdf3

fix: Validate RequestContext for context_id and message before execution

a3a5c48

eavanvalkenburg reviewed Nov 25, 2025

View reviewed changes

		from agent_framework import ChatMessage, DataContent, Role, TextContent, UriContent


		class A2aEventAdapter(ABC):

	class BaseA2aEventAdapter(A2aEventAdapter):
	class BaseA2AEventAdapter(A2aEventAdapter):

	parts.append(Part(root=FilePart(file=FileWithBytes(bytes=_extract_base64_from_uri(content.uri)))))
	parts.append(Part(root=FilePart(file=FileWithBytes(bytes=content.get_data_bytes())))

	root=FilePart(file=FileWithUri(uri=content.uri, mime_type=getattr(content, "media_type", None)))
	root=FilePart(file=FileWithUri(uri=content.uri, mime_type=content.media_type))

		from ._a2a_event_adapter import A2aEventAdapter, BaseA2aEventAdapter


		class A2aExecutor(AgentExecutor):

		self.message_store = ChatMessageStore(messages=state.chat_message_store_state.messages, **kwargs)


		class AgentThreadStorage(ABC):

Python: feat: Add Agent Framework to A2A bridge support #2403

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Shubham-Kumar-2000 commented Nov 25, 2025

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Shubham-Kumar-2000 commented Nov 23, 2025 •

edited

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