agents 1.4.0

Dart port of the Microsoft Agents AI framework. Build, compose, and orchestrate AI agents backed by any ChatClient — with sessions, streaming, tool use, compaction, evaluation, and middleware pipelines.

Changelog

1.4.0

• Add loop agents under harness/loop/: LoopAgent and LoopAgentOptions run an inner agent repeatedly until an evaluator signals completion, with pluggable LoopEvaluator strategies — AIJudgeLoopEvaluator, CompletionMarkerLoopEvaluator, TodoCompletionLoopEvaluator, and DelegateLoopEvaluator — plus LoopContext, LoopEvaluation, and JudgeVerdict support types.
• Add Magentic multi-agent orchestration to the workflows engine: MagenticWorkflowBuilder, MagenticOrchestrator, the plan-review request/response messages, and the progress ledger (ports the upstream Magentic manager/orchestrator pattern).
• Add OpenAI-compatible hosting under hosting/open_ai/: shelf-based routers and handlers for the Chat Completions, Conversations, and Responses APIs, backed by in-memory storage, exposed through open_ai_hosting_service_collection_extensions.
• Add shelf: ^1.4.0 and shelf_router: ^1.1.0 dependencies for the OpenAI hosting routers.
• Fix fan-in edges losing buffered messages across checkpoint/resume: pending fan-in contributions are now captured in Checkpoint.fanInState and restored on resume (both the in-proc and legacy execution engines). Old checkpoint JSON without the field remains loadable.
• Fix fan-in edges dropping all but the last message from a source that sent more than once before the edge released; all buffered messages are now delivered, ordered by source then arrival (matches upstream FanInEdgeState semantics).
• Fix streamed responses losing responseId, messageId, createdAt, usage, modelId, rawRepresentation, and additionalProperties when coalesced by ChatClientAgent and PerServiceCallChatHistoryPersistingChatClient; all call sites now share one toChatResponse() extension (ports C# ToChatResponse).
• Fix A2AAgentSession.serialize() dropping the session stateBag; it now round-trips, and legacy payloads without it remain loadable.
• Remove the unused StatefulEdgeRunner interface (breaking; it had no implementors — fan-in state is checkpointed via Checkpoint.fanInState).
• Rename agent_response_t_.dart → agent_response_of.dart and provider_session_state_t_state_.dart → provider_session_state.dart (library paths only; type names unchanged).
• Simplify shell executor timeout handling with a shared waitForProcessExit helper; removes an unmanaged kill timer and ensures the force-kill is awaited before draining output.

1.2.0

• Add A2A (Agent-to-Agent) protocol support:
  • Client-side A2AAgent, A2AAgentOptions, A2AAgentSession, and A2AContinuationToken for consuming remote agents over the A2A protocol.
  • a2a_client_extensions and a2a_agent_card_extensions helpers.
  • Server-side hosting bridge: A2AAgentHandler, A2ARunDecisionContext, A2AServerRegistrationOptions, agentRunMode, the a2a_server_service_collection_extensions registration helpers, and a MessageConverter.
• Add a2a: ^4.2.0 dependency.

1.1.0

• Previous release.