Files
SergeyMenshykh 66e02c10e3 .NET: [Breaking] Migrate A2A agent and hosting to A2A SDK v1 (#5423)
* update a2a agent to the latest a2a sdk (#5257)

* Move A2A samples from 04-hosting to 02-agents (#5267)

Move the A2A sample projects (A2AAgent_AsFunctionTools and
A2AAgent_PollingForTaskCompletion) from samples/04-hosting/A2A/ to
samples/02-agents/A2A/ to better align with the sample directory
structure. Update solution file and samples README accordingly.

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

* .NET: Fix stream reconnection for A2AAgent (#5275)

* Add SSE stream reconnection support to A2AAgent

Implement automatic reconnection for SSE streams that disconnect mid-task,
using the Last-Event-ID header to resume from where the stream left off.

Changes:
- Add InvokeStreamingWithReconnectAsync method to A2AAgent with configurable
  max retries and delay between attempts
- Add new log messages for reconnection events
- Add A2AAgent_StreamReconnection sample demonstrating the feature
- Update existing polling sample to use simplified SendMessageAsync API
- Add unit tests for stream reconnection logic

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

* address comments

* Address PR review feedback

- Dispose SSE enumerator before GetTaskAsync fallback to release HTTP connection
- Wrap StreamWriter in using blocks with leaveOpen:true and explicit UTF-8 encoding
- Print update.Text instead of update object in stream reconnection sample

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

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

* .NET: Use IA2AClientFactory to create A2AClient (#5277)

* Refactor A2A extensions to use IA2AClientFactory and add ProtocolSelection sample

- Update A2AAgentCardExtensions to accept IA2AClientFactory instead of A2AClientOptions
- Update A2ACardResolverExtensions to accept IA2AClientFactory
- Update A2AClientExtensions to accept IA2AClientFactory
- Update A2AAgent to use IA2AClientFactory for client creation
- Add A2AAgent_ProtocolSelection sample demonstrating protocol selection
- Add comprehensive unit tests for all changes
- Update README files with new sample reference

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

* Reorder params: options before loggerFactory in A2A extensions

Move A2AClientOptions parameter before ILoggerFactory in AsAIAgent
and GetAIAgentAsync extension methods to follow the repo convention
of keeping LoggerFactory and CancellationToken as the last parameters.

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

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

* .NET: Migrate A2A hosting to A2A SDK v1 (#5363)

* .NET: Migrate A2A hosting to A2A SDK v1

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

* remove unused agent card

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

* .NET: Split A2A endpoint mapping into protocol-specific methods (#5413)

* .NET: Refactor A2A hosting registration into A2AServerServiceCollectionExtensions

- Rename A2AHostingOptions to A2AServerRegistrationOptions
- Move server registration logic from A2AEndpointRouteBuilderExtensions
  and AIAgentExtensions into new A2AServerServiceCollectionExtensions
- Remove A2AProtocolBinding and AIAgentExtensions (consolidated)
- Update samples and tests to use the new registration API

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

* address copilot comments

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

* Remove unnecessary using directive in AgentWebChat.AgentHost

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

* restore AsyncEnumerable package version

* address copilot initial feedback

* address automated code review and formatting issues

* fix formatting issues

* Add DI wiring verification tests for AddA2AServer

Add three tests to A2AServerServiceCollectionExtensionsTests that verify
custom keyed services are actually wired through to the A2AServer, not
just that the server resolves non-null:

- Custom IAgentHandler: verifies the keyed handler is invoked when
  processing a SendMessageRequest instead of the default A2AAgentHandler.
- Custom AgentSessionStore (no handler): verifies the keyed session
  store's GetSessionAsync is called during request processing when no
  custom handler is registered.
- Default stores end-to-end: verifies the InMemoryAgentSessionStore and
  InMemoryTaskStore defaults successfully process a request. Uses a new
  CreateAgentMockForRequests helper that includes SerializeSessionCoreAsync
  setup needed by InMemoryAgentSessionStore.

All tests call A2AServer.SendMessageAsync directly (no HTTP layer needed)
and use CancellationToken timeouts to guard against hangs.

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

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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-04-23 07:53:00 +00:00

2.2 KiB

Agent-to-Agent (A2A) Samples

These samples demonstrate how to work with Agent-to-Agent (A2A) specific features in the Agent Framework.

For other samples that demonstrate how to use AIAgent instances, see the Getting Started With Agents samples.

Prerequisites

See the README.md for each sample for the prerequisites for that sample.

Samples

Sample Description
A2A Agent As Function Tools This sample demonstrates how to represent an A2A agent as a set of function tools, where each function tool corresponds to a skill of the A2A agent, and register these function tools with another AI agent so it can leverage the A2A agent's skills.
A2A Agent Polling For Task Completion This sample demonstrates how to poll for long-running task completion using continuation tokens with an A2A agent.
A2A Agent Stream Reconnection This sample demonstrates how to reconnect to an A2A agent's streaming response using continuation tokens, allowing recovery from stream interruptions.
A2A Agent Protocol Selection This sample demonstrates how to select the A2A protocol binding (HTTP+JSON vs JSON-RPC) when creating an AIAgent from an A2A agent card using A2AClientOptions.

Running the samples from the console

To run the samples, navigate to the desired sample directory, e.g.

cd A2AAgent_AsFunctionTools

Set the required environment variables as documented in the sample readme. If the variables are not set, you will be prompted for the values when running the samples. Execute the following command to build the sample:

dotnet build

Execute the following command to run the sample:

dotnet run --no-build

Or just build and run in one step:

dotnet run

Running the samples from Visual Studio

Open the solution in Visual Studio and set the desired sample project as the startup project. Then, run the project using the built-in debugger or by pressing F5.

You will be prompted for any required environment variables if they are not already set.