microsoft/agent-host-protocol clients/go/v0.5.0

Go module v0.5.0

Repository: microsoft/agent-host-protocol

Tag: clients/go/v0.5.0

Published: 2026-06-26T23:23:24Z

Prerelease: no

Release notes:

[0.5.0] — 2026-06-26

Implements AHP 0.5.0.

Added

• ChatDraftChangedAction (wire chat/draftChanged) and ChatState.Draft

(*Message) for syncing a chat's in-progress input draft; ApplyActionToChat sets or clears state.Draft without stamping ModifiedAt.

• Message.Model and Message.Agent optional fields recording the model /

agent selection a message was composed with.

• ChatActivityChangedAction (wire chat/activityChanged) for updating a chat's

current activity description independently of the session summary.

• ProgressParams struct (wire root/progress) — a generic progress notification

correlated by a ProgressToken (added on CreateSessionParams). Used today for the lazy first-use download of an agent's native SDK.

• SessionModelInfo.MaxOutputTokens and SessionModelInfo.MaxPromptTokens

optional fields for communicating model token limits.

• SessionSummary.Meta (wire _meta) optional provider metadata field for

lightweight session-list presentation hints.

• SessionActiveClientRemovedAction (wire session/activeClientRemoved) to

release a single active client by ClientId.

Changed

• SessionState no longer embeds a Summary sub-struct; its metadata fields

(Provider, Title, Status, Activity, Project, WorkingDirectory, Annotations) are now inlined directly on SessionState, which no longer carries Model, Agent, CreatedAt, or ModifiedAt. ApplyActionToSession reads and writes these flat fields and no longer stamps a session ModifiedAt.

• SessionSummary is now a root-only catalog struct; its CreatedAt /

ModifiedAt are ISO-8601 strings (previously numeric) and it no longer carries Model / Agent.

• ChatState and ChatSummary no longer carry Model / Agent.
• SessionState.ActiveClients ([]SessionActiveClient, required) replaces the

single pointer SessionState.ActiveClient; ApplyActionToSession upserts and removes entries keyed by ClientId.

• SessionActiveClientChangedAction is renamed to SessionActiveClientSetAction

(wire session/activeClientSet) with upsert-by-ClientId semantics; it no longer unsets the active client (dispatch session/activeClientRemoved instead).

• ConfigPropertySchema.Enum field is now []json.RawMessage instead of []string,

allowing numeric, boolean, and null enum values.

• ModelSelection.Config values are now json.RawMessage instead of string,

allowing numeric, boolean, and null configuration values.

Removed

• SessionModelChangedAction (wire session/modelChanged) and

SessionAgentChangedAction (wire session/agentChanged); session model / agent are no longer part of the protocol surface.

• SessionActiveClientToolsChangedAction. An active client now updates its

published tools by re-dispatching SessionActiveClientSetAction with its full, updated entry.