HookMessageWriter

Background

Chat hardcodes message origin per method (user() → User, assistant() → Model, etc.). Hooks that queue messages via the queue-message action need to set origin: Hook.

Interfaces

Two separate interfaces keep the concerns apart:

• MessageWriter — clean interface without origin params. Used by Chat and the public service.queue() API.
• HookMessageWriter — same methods but with a required origin param. Used internally by hooks.

MessageQueue implements both. Each method accepts an optional origin: when called via MessageWriter the caller omits it (default User/Tool), when called via HookMessageWriter the caller passes it explicitly (e.g. ChatMessageOrigin.Hook).

Wiring

JsonHookRegistry receives a HookMessageWriter and a JsonHookControls object via constructor injection:

constructor(
    private _hookWriter?: HookMessageWriter,
    private _controls?: JsonHookControls
)

ChatService passes this._messageQueue (as HookMessageWriter) and this (as JsonHookControls).

JsonHookControls is a minimal interface replacing the old JsonHookService:

export interface JsonHookControls {
    setNeedsResend(): void;
    interrupt(needsResend?: boolean): void;
}

ChatMessageOrigin

Every ChatMessage carries a required origin field:

Value	Source
User	chat.user(), queue().user()
Model	chat.assistant(), chat.reasoning()
Tool	chat.tool(), queue().tool()
Hook	Hook queue-message action
System	System prompt via chat.getSystem()

Files

File	Role
src/chats/chat.ts	MessageWriter, HookMessageWriter, ChatMessageOrigin, ChatMessage.origin
src/chats/queue.ts	MessageQueue implements both writer interfaces
src/hooks/json-hooks.ts	JsonHookControls, JsonHookRegistry accepts hook writer + controls
src/chats/service.ts	ChatService implements JsonHookControls, wires MessageQueue to registry
src/index.ts	Public API exports (does NOT re-export hook-internal types)