- release-please GitHub App is being turned down on August 15, 2025

We want to use this in a project that requires `protobuf==6.31.1`.
Version history indicates upgrading a2a-python to that version is not
possible at the moment. Therefore, relax the required version to just be
`>=5.29.5` (instead of `==`).

This does print a warning when using a2a-python with a (major) newer
version, but my tests show that it works just fine. Better to live with
the warning than not being able to use a2a-python at all.

This does not update the buf generation config as this would upgrade to
newer proto requirements (and generate protos for newer versions).

Using `response.task` will reset the oneof field if the `msg` field was
set. Properly check return value.

---------

Co-authored-by: pstephengoogle <pstephen@google.com>

The `A2AFastAPIApplication` is very useful, but currently can not be
used as a [Sub
Application](https://fastapi.tiangolo.com/advanced/sub-applications/)
without breaking the openapi specification.
[Lifespan does not work for Sub
Applications](https://fastapi.tiangolo.com/advanced/events/#sub-applications),
which makes this otherwise useful integration work in existing larger
FastAPI apps.

This fix gets rid of the lifespan and instead enriches the openapi on
the first call of the [openapi
method](https://github.com/fastapi/fastapi/blob/0.116.1/fastapi/applications.py#L966).

I tested it locally and everything works with sub-application.

The following works after the fix with openapi components populated:
```python
from fastapi import FastAPI
from a2a.server.apps import A2AFastAPIApplication
app = FastAPI()
agent_app = A2AFastAPIApplication(...).build()
app.mount("/a2a", agent_app)
```

I am not adding `@override` although this overrides the `openapi`,
because the pyright fails on it, see [the failed lint
run](https://github.com/a2aproject/a2a-python/actions/runs/16370448989/job/46257297467?pr=324).

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: Holt Skinner <13262395+holtskinner@users.noreply.github.com>
Co-authored-by: kthota-g <kcthota@google.com>

Fixes a2aproject/A2A#861

# Description

This callback shouldn't result in exceptions being raised. From docs on
`.exception()`:

> The exception (or None if no exception was set) is returned only if
the future is done. If the future has been cancelled, raises
CancelledError. If the future isn't done yet, raises InvalidStateError.

Currently, if a task has been cancelled, exceptions are thrown. E.g. the
following error was observed when used with `google-adk`

```
ERROR:asyncio:Exception in callback EventConsumer.agent_task_callback() at /app/python/.venv/lib/python3.13/site-packages/a2a/server/events/event_consumer.py:153
handle: <Handle EventConsumer.agent_task_callback() at /app/python/.venv/lib/python3.13/site-packages/a2a/server/events/event_consumer.py:153>
Traceback (most recent call last):
  File "/app/python/.venv/lib/python3.13/site-packages/anyio/streams/memory.py", line 111, in receive
    return self.receive_nowait()
           ~~~~~~~~~~~~~~~~~~~^^
  File "/app/python/.venv/lib/python3.13/site-packages/anyio/streams/memory.py", line 106, in receive_nowait
    raise WouldBlock
anyio.WouldBlock

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/app/python/.local/share/uv/python/cpython-3.13.5-linux-x86_64-gnu/lib/python3.13/asyncio/events.py", line 89, in _run
    self._context.run(self._callback, *self._args)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/python/.venv/lib/python3.13/site-packages/a2a/utils/telemetry.py", line 202, in sync_wrapper
    result = func(*args, **kwargs)
  File "/app/python/.venv/lib/python3.13/site-packages/a2a/server/events/event_consumer.py", line 163, in agent_task_callback
    if agent_task.exception() is not None:
       ~~~~~~~~~~~~~~~~~~~~^^
  File "/app/python/.venv/lib/python3.13/site-packages/a2a/utils/telemetry.py", line 162, in async_wrapper
    result = await func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/python/.venv/lib/python3.13/site-packages/a2a/server/request_handlers/default_request_handler.py", line 172, in _run_event_stream
    await self.agent_executor.execute(request, queue)
  File "/app/python/packages/kagent-adk/src/kagent_adk/_agent_executor.py", line 124, in execute
    await self._handle_request(context, event_queue, runner)
  File "/app/python/packages/kagent-adk/src/kagent_adk/_agent_executor.py", line 188, in _handle_request
    async for adk_event in runner.run_async(**run_args):
    ...<4 lines>...
            await event_queue.enqueue_event(a2a_event)
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/runners.py", line 233, in run_async
    async for event in self._exec_with_plugin(
    ...<2 lines>...
      yield event
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/runners.py", line 273, in _exec_with_plugin
    async for event in execute_fn(invocation_context):
    ...<6 lines>...
      yield (modified_event if modified_event else event)
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/runners.py", line 230, in execute
    async for event in ctx.agent.run_async(ctx):
      yield event
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/agents/base_agent.py", line 209, in run_async
    async for event in self._run_async_impl(ctx):
      yield event
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/agents/llm_agent.py", line 283, in _run_async_impl
    async for event in self._llm_flow.run_async(ctx):
      self.__maybe_save_output_to_state(event)
      yield event
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/flows/llm_flows/base_llm_flow.py", line 290, in run_async
    async for event in self._run_one_step_async(invocation_context):
      last_event = event
      yield event
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/flows/llm_flows/base_llm_flow.py", line 322, in _run_one_step_async
    async for event in self._postprocess_async(
    ...<5 lines>...
      yield event
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/flows/llm_flows/base_llm_flow.py", line 407, in _postprocess_async
    async for event in self._postprocess_handle_function_calls_async(
    ...<2 lines>...
      yield event
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/flows/llm_flows/base_llm_flow.py", line 482, in _postprocess_handle_function_calls_async
    if function_response_event := await functions.handle_function_calls_async(
                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        invocation_context, function_call_event, llm_request.tools_dict
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ):
    ^
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/flows/llm_flows/functions.py", line 179, in handle_function_calls_async
    function_response = await __call_tool_async(
                        ^^^^^^^^^^^^^^^^^^^^^^^^
        tool, args=function_args, tool_context=tool_context
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/flows/llm_flows/functions.py", line 474, in __call_tool_async
    return await tool.run_async(args=args, tool_context=tool_context)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/tools/base_authenticated_tool.py", line 93, in run_async
    return await self._run_async_impl(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<3 lines>...
    )
    ^
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/tools/mcp_tool/mcp_session_manager.py", line 128, in wrapper
    return await func(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/python/.venv/lib/python3.13/site-packages/google/adk/tools/mcp_tool/mcp_tool.py", line 133, in _run_async_impl
    response = await session.call_tool(self.name, arguments=args)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/python/.venv/lib/python3.13/site-packages/mcp/client/session.py", line 293, in call_tool
    result = await self.send_request(
             ^^^^^^^^^^^^^^^^^^^^^^^^
    ...<12 lines>...
    )
    ^
  File "/app/python/.venv/lib/python3.13/site-packages/mcp/shared/session.py", line 272, in send_request
    response_or_error = await response_stream_reader.receive()
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/python/.venv/lib/python3.13/site-packages/anyio/streams/memory.py", line 119, in receive
    await receive_event.wait()
  File "/app/python/.venv/lib/python3.13/site-packages/anyio/_backends/_asyncio.py", line 1774, in wait
    await self._event.wait()
  File "/app/python/.local/share/uv/python/cpython-3.13.5-linux-x86_64-gnu/lib/python3.13/asyncio/locks.py", line 213, in wait
    await fut
asyncio.exceptions.CancelledError: Cancelled by cancel scope 72d19ee594f0
```

Commit:
a2aproject/A2A@cab1bc3

# Description

This update makes Starlette and FastAPI libraries as optional
dependencies. Users can run `uv add a2a-sdk[http-server]` to install
these dependencies.

## Additional Checks

- Verified that the "helloworld" agent sample works with this change.
- Verified that a reasonable error message is printed when trying to use
`A2AFastAPIApplication`.

Release-As: 0.3.0

---------

Co-authored-by: Holt Skinner <13262395+holtskinner@users.noreply.github.com>
Co-authored-by: Holt Skinner <holtskinner@google.com>

Google GitHub App will be deprecated

The action "Test with Python 3.13" does not work as expected, all tests
are run with Python 3.10.

For exemple, [this
run](https://github.com/a2aproject/a2a-python/actions/runs/16851324550/job/47738005154)
shows:

```
Test with Python 3.13
...
Run uv run pytest --cov=a2a --cov-report term --cov-fail-under=88
============================= test session starts ==============================
platform linux -- Python 3.10.18, pytest-8.4.1, pluggy-1.6.0
```

I modified the script to set `python-version` on the "Install uv" step,
this is the one that really creates the Python installation.
Then I fixed the tests, they should work with all Pythons now.

### Description

This update introduces upfront validation for transport protocols within
the `ClientFactory`. Previously, if an invalid or misspelled transport
type was provided in the `ClientConfig`, it would be silently ignored.
This could lead to confusing `ValueError('no compatible transports
found.')` errors later on, making it difficult to debug
misconfigurations.

### Changes

* **`src/a2a/client/client_factory.py`**: Added a validation loop at the
beginning of the `create` method to check all transport types provided
in the `ClientConfig`.
* **`tests/client/test_client_factory.py`**: Added a new unit test,
`test_client_factory_invalid_transport_in_config`, to confirm that a
`ValueError` is raised when an invalid transport string is used.

…ls (#392)

# Description

Thank you for opening a Pull Request!
Before submitting your PR, there are a few things you can do to make
sure it goes smoothly:

- [ ] Follow the [`CONTRIBUTING`
Guide](https://github.com/a2aproject/a2a-python/blob/main/CONTRIBUTING.md).
- [ ] Make your Pull Request title in the
<https://www.conventionalcommits.org/> specification.
- Important Prefixes for
[release-please](https://github.com/googleapis/release-please):
- `fix:` which represents bug fixes, and correlates to a
[SemVer](https://semver.org/) patch.
- `feat:` represents a new feature, and correlates to a SemVer minor.
- `feat!:`, or `fix!:`, `refactor!:`, etc., which represent a breaking
change (indicated by the `!`) and will result in a SemVer major.
- [ ] Ensure the tests and linter pass (Run `bash scripts/format.sh`
from the repository root to format)
- [ ] Appropriate docs were updated (if necessary)

Fixes #<issue_number_goes_here> 🦕

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: Holt Skinner <13262395+holtskinner@users.noreply.github.com>
Co-authored-by: Holt Skinner <holtskinner@google.com>

…402)

Reverts #396

This PR shouldn't have been merged as we don't want to limit the
protocol to only JSON-RPC, gRPC, and REST Transports. (e.g. for
proprietary transport protocols)

Reported by @yarolegovich

🤖 I have created a release *beep* *boop*
---


##
[0.3.1](v0.3.0...v0.3.1)
(2025-08-13)


### Features

* Add agent card as a route in rest adapter
([ba93053](ba93053))


### Bug Fixes

* gracefully handle task exceptions in event consumer
([#383](#383))
([2508a9b](2508a9b))
* openapi working in sub-app
([#324](#324))
([dec4b48](dec4b48))
* Pass `message_length` param in `get_task()`
([#384](#384))
([b6796b9](b6796b9))
* relax protobuf dependency version requirement
([#381](#381))
([0f55f55](0f55f55))
* Use HasField for simple message retrieval for grpc transport
([#380](#380))
([3032aa6](3032aa6))

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

---------

Co-authored-by: Holt Skinner <13262395+holtskinner@users.noreply.github.com>