spec/v0.5.1 clients/go/v0.5.1
microsoft/agent-host-protocolJul 2, 2026 → Jul 2, 20260 days between releases
What's New
Go client v0.5.1 implements the AHP 0.5.1 spec, adding session-level input tracking, pagination, and capability gating.
Breaking Changes
- The `Filter` field is removed from `ListSessionsParams`, so callers relying on it must drop or replace that usage.
- The `fetchTurns` contract is incompatible with 0.5.0, requiring callers to adapt to the new turn-loading model.
New Features
- Session-level `InputNeeded` aggregate with `SessionInputNeededSetAction`/`SessionInputNeededRemovedAction` lets clients answer elicitations and tool requests without subscribing to individual chats.
- Cursor-based pagination via shared `PaginatedParams` (`Limit`/`Cursor`) and `PaginatedResult` (`NextCursor`) on `listSessions`.
- `SubscribeWithDelivery` and `SubscribeParams.Delivery.MaxLatencyMs` let clients cap subscription delivery latency, including zero for no coalescing.
- `AgentInfo.Capabilities` with nested `multipleChats.fork` enables capability-based gating of multi-chat and fork features.
- Bounded turn subscription via `SubscribeParams.View.Turns`, `ChatState.TurnsNextCursor`, and the `chat/turnsLoaded` action for paging older history on demand.
Improvements
- Capability-based gating replaces provider-id switches for multi-chat and fork decisions.
- Optional `Nonce` on `ContentRef`, `Intention` on tool calls, and `Model`/`Tools` on `AgentCustomization` are now exposed in the Go client.
- Pagination additions are fully additive, preserving prior behavior when the new fields are omitted.
Upgrade Notes
Go client users coming from 0.5.0 must remove the `Filter` field from `ListSessionsParams` and adapt to the new `fetchTurns` contract. Adopt the new pagination types and capability checks to use multi-chat and fork features. Most other additions are optional and additive, so existing code compiles with minimal changes beyond the breaking items.
The Two Releases
AHP Spec v0.5.1
Jul 2, 2026· 4 months ago
Defines the protocol spec for AHP 0.5.1, defining session-level input tracking, pagination, and capability checks for multi-chat scenarios.
Full release notesGo module v0.5.1
Jul 2, 2026· 4 months ago
Go client implementation of AHP 0.5.1, adding session-level input tracking and pagination support to the client library.
Full release notes