Generate structured PRD (Product Requirements Document) planning documents optimized for AI-assisted development. Creates discrete, single-conversation tasks with reasoning level estimates to optimize token usage and model selection. Use when users want to plan implementation work, break down features into tasks, create implementation roadmaps, or structure development work for AI pair programming. Triggers on phrases like "create a PRD", "plan this feature", "break down this task", "implementation plan", "create threads for", or "help me plan".