What problem does it solve? Building or debugging the in-event Social Icebreaker requires coordinating a phase-ordered session state machine, host/player authority boundaries, rejoin semantics, and AI generation fallbacks across server routes and two client platforms, which is error-prone without a single source of truth. ## Core Features & Use Cases - Session Lifecycle Governance: Documents the full flow from POST /start through phase advance, bonus gate, recap, and 6-hour TTL sweep, including rejoin via upsertParticipant and 410 SESSION_EXPIRED semantics. - Authority & Phase Guards: Defines host-only actions (advance, generate, tier change) versus player self-state mutations, plus per-phase advance guards and cleanup rules. - AI Integration Boundaries: Maps every LLM generator to its route, promptVersion, logAITrace domain, 6-second raceWithTimeout wrapper, and curated fallback behavior. - Use Case: When adding a new phase between warmup and micro_challenge, follow the checklist to update PHASE_ORDER, advance guards, both client registries, and feature flags without breaking cross-platform parity. ## Quick Start Ask the AI to walk through adding a new phase to the social icebreaker session flow using this skill's phase order, advance guards, and review checklist.