Method executeSessionStartHooks

pkg/runtime/hooks.go:146–151

executeSessionStartHooks fires session_start once at the top of RunStream and returns its AdditionalContext as transient system messages. The result is NOT persisted to the session: persisting would pollute the visible transcript and (because session_start fires after the user message has been added

(ctx context.Context, sess *session.Session, a *agent.Agent, events EventSink)

// dispatch — there's nothing to "re-inject" because nothing was
// persisted in the first place.
func (r *LocalRuntime) executeSessionStartHooks(ctx context.Context, sess *session.Session, a *agent.Agent, events EventSink) []chat.Message {
	return contextMessages(r.dispatchHook(ctx, a, hooks.EventSessionStart, &hooks.Input{
		SessionID: sess.ID,
		Source:    "startup",
	}, events))
}

// executeTurnStartHooks fires turn_start before each model call and
// returns its AdditionalContext as transient system messages. Like