Files
agent-framework/python/packages/a2a
T
Giles Odigwe efdabd56dc feat(a2a): add A2AAgentSession with reference_task_ids and input-required support (#5980)
* feat(a2a): link follow-up messages via reference_task_ids

Track the task_id from A2A responses (task, status_update, artifact_update,
and message payloads) on session.state and include it as reference_task_ids
on subsequent outgoing messages. This enables remote agents to correlate
follow-up messages as task refinements per the A2A spec.

Resolves #5938

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* feat(a2a): add A2AAgentSession for typed protocol state tracking

Introduce A2AAgentSession (subclass of AgentSession) with context_id,
task_id, and task_state properties. This follows the DurableAgentSession
pattern and mirrors the .NET A2AAgentSession design.

- Track task_id, context_id, and task_state from all response payload types
- Validate context_id consistency (raise on mismatch)
- Auto-assign server-generated context_id when not set
- Only A2AAgentSession gets reference tracking (no state dict fallback)
- Plain AgentSession continues to work without reference tracking
- Add serialization support (to_dict/from_dict)
- Export via agent_framework.a2a and agent_framework_a2a

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* style: remove unnecessary string annotation (pyupgrade)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: use AgentSession.from_dict for state deserialization

Avoids importing private _deserialize_state, matching the
DurableAgentSession pattern.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: track context_id from message payloads in A2AAgentSession

Previously, context_id was only captured from task, status_update, and
artifact_update payloads. Message-only responses (which carry context_id
but may lack task_id) were silently lost. This fix:

- Captures msg.context_id in the message handler
- Persists session state when either last_task_id or last_context_id is
  present (not only when task_id is truthy)
- Only updates task_id/task_state when a task_id was actually returned
- Adds a test for message-only context_id tracking

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* addressed comments

* Gate status content to INPUT_REQUIRED/terminal states (match .NET)

Match .NET's GetUserInputRequests pattern: only emit TaskStatusUpdateEvent
message content when state is INPUT_REQUIRED or terminal. Intermediate
status text (WORKING, SUBMITTED) is no longer surfaced to callers.

When state is INPUT_REQUIRED, set additional_properties['input_required']
= True so callers can distinguish input requests from final responses.

Closes #5937

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review: remove message task_id tracking, defensive fallbacks, and input_required flag

- Do not track task_id from Message payloads (simple interactions
  without task tracking)
- Remove 'or last_task_id' fallback from status_update and
  artifact_update handlers (spec guarantees task_id is always set)
- Remove additional_properties['input_required'] flag (content gating
  to INPUT_REQUIRED/terminal states is the signal itself)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
efdabd56dc ยท 2026-05-28 08:36:49 +00:00
History
..

Get Started with Microsoft Agent Framework A2A

Please install this package via pip:

pip install agent-framework-a2a --pre

A2A Agent Integration

The A2A agent integration enables communication with remote A2A-compliant agents using the standardized A2A protocol. This allows your Agent Framework applications to connect to agents running on different platforms, languages, or services.

A2AAgent (Client)

The A2AAgent class is a client that wraps an A2A Client to connect the Agent Framework with external A2A-compliant agents.

from agent_framework.a2a import A2AAgent

# Connect to a remote A2A agent
a2a_agent = A2AAgent(url="http://remote-agent/a2a")
response = await a2a_agent.run("Hello!")

A2AExecutor (Hosting)

The A2AExecutor class bridges local AI agents built with the agent_framework library to the A2A protocol, allowing them to be hosted and accessed by other A2A-compliant clients.

from agent_framework.a2a import A2AExecutor
from a2a.server.apps import A2AStarletteApplication
from a2a.server.request_handlers import DefaultRequestHandler
from a2a.server.tasks import InMemoryTaskStore

# Create an A2A executor for your agent
executor = A2AExecutor(agent=my_agent)

# Set up the request handler and server application
request_handler = DefaultRequestHandler(
    agent_executor=executor,
    task_store=InMemoryTaskStore(),
)

app = A2AStarletteApplication(
    agent_card=my_agent_card,
    http_handler=request_handler,
).build()

Basic Usage Example

See the A2A agent examples which demonstrate:

  • Connecting to remote A2A agents
  • Hosting local agents via A2A protocol
  • Sending messages and receiving responses
  • Handling different content types (text, files, data)
  • Streaming responses and real-time interaction