What's Changed

• feat: .net api for the a2a protocol by @SergeyMenshykh in #1
• Fix up dependencies / project files by @stephentoub in #5
• feat: Combine A2A and A2A.Core packages by @stephentoub in #8
• feat: Add NativeAOT support by @stephentoub in #12
• feat: add initial unit tests and minor clean-ups by @SergeyMenshykh in #11
• feat: Turn on more analyzers and clean up by @stephentoub in #13
• feat: add unit tests by @SergeyMenshykh in #14
• feat: enable code analysis by @SergeyMenshykh in #15
• feat: Avoid intermediate MemoryStream in JsonRpcContent by @stephentoub in #16
• feat: Remove extraneous error types by @stephentoub in #17
• feat: Simplify SSE formatting by @stephentoub in #18
• Update README.md - remove none-existing library by @Meir017 in #19
• feat: Clean up A2AClient by @stephentoub in #27
• feat: Clean up A2ACardResolver by @stephentoub in #28
• feat: add protocol version by @SergeyMenshykh in #31
• feat: add xml documentation by @SergeyMenshykh in #29
• fix: fix sse deserialization by @SergeyMenshykh in #35
• feat: add AdditionalInterfaces and PreferredTransport props by @SergeyMenshykh in #34
• feat: Remove custom JSON converters for enums by @stephentoub in #32
• feat: model clean-up by @SergeyMenshykh in #36
• feat: seal api and clean up a2aclient tests by @SergeyMenshykh in #37
• refactor(a2a): align HTTP endpoints with proto file by @datnq26 in #26
• Update to latest System.CommandLine by @adamsitnik in #39
• Make sure public methods throw on invalid input by @adamsitnik in #41
• make A2AHttpProcessor as it does not expose any public methods by @adamsitnik in #42
• feat: support extensions and icon url by @SergeyMenshykh in #44
• feat: release definition by @SergeyMenshykh in #48
• feat: support for multiple push notifications by @SergeyMenshykh in #43
• chore: remove client project by @SergeyMenshykh in #50
• feat: move .well-known/agent.json endpoint to app root by @SergeyMenshykh in #59
• chore: update editconfig by @SergeyMenshykh in #60
• chore: clean up by @SergeyMenshykh in #64
• fix: Handle HistoryLength by @brandonh-msft in #61
• feat: error handling and input validation by @SergeyMenshykh in #63
• fix: Update message and message stream to match latest spec by @brandonh-msft in #62
• fix: Resolve remaining compliance issues by @brandonh-msft in #65
• build(deps): bump actions/download-artifact from 4.2.1 to 4.3.0 by @dependabot[bot] in #51
• Fix: capability issues by @brandonh-msft in #66
• feat: add cancellation token by @SergeyMenshykh in #70
• chore: Add Async suffix to async method missing it by @SergeyMenshykh in #75
• fix: Improve streaming support by @adamsitnik in #74
• fix: use ConfigureAwait(false) for async calls by @brandonh-msft in #76
• chore: add cancellation token requested checks to in-memory task store by @SergeyMenshykh in #80
• refactor: exception handling logic by @adamsitnik in #69
• feat: make OnAgentCardQuery async by @adamsitnik in #86
• fix: ensure OnAgentCardQuery is awaited and returns a valid JSON by @adamsitnik in #87
• fix: always call async methods when in an async context and do await them by @adamsitnik in #89
• perf: use source generated logging by @brandonh-msft in #78
• feat: add a2aclient samples by @SergeyMenshykh in #93
• fix: don't augment task when trimming history by @brandonh-msft in #94
• fix: make WithHistoryTrimmedTo an internal extension method by @brandonh-msft in #96
• feat: spec compliance agent by @SergeyMenshykh in #98
• chore: update readme to reflect latest API changes by @SergeyMenshykh in #100
• fix: don't use Task<IAsyncEnumerable> by @brandonh-msft in #90
• chore: update readme and bump protocol version by @SergeyMenshykh in #101
• fix: reject empty part arrays and negative history length by @adamsitnik in #99
• fix: agent client samples open many console windows by @SergeyMenshykh in #106
• fix: Task state quality issues by @adamsitnik in #103
• fix: make InMemoryTaskStore thread-safe by @adamsitnik in #104
• feat: add a new IDistributedCache based implementation of the ITaskStore by @cdavernas in #92
• fix: TaskId validation: enforce existing task requirement per A2A protocol by @Copilot in #112
• fix: Add missing OpenAPI Security Scheme Object properties and MutualTLS support by @Copilot in #109
• chore: release prep by @SergeyMenshykh in #121

New Contributors

• @SergeyMenshykh made their first contribution in #1
• @stephentoub made their first contribution in #5
• @Meir017 made their first contribution in #19
• @datnq26 made their first contribution in #26
• @adamsitnik made their first contribution in #39
• @brandonh-msft made their first contribution in #61
• @dependabot[bot] made their first contribution in #51
• @cdavernas made their first contribution in #92
• @Copilot made their first contribution in #112

Full Changelog: https://github.com/a2aproject/a2a-dotnet/commits/v0.1.0-preview.2