Add a wildcard (any-type) optional 'signal' input to Agent Receive. Wiring any upstream output into it creates a dependency edge so ComfyUI runs that node first — e.g. force an Agent Emit (send the prompt) to fire before Receive starts waiting. The value is ignored; presence is what orders execution. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>