This capstone chains three skills in sequence — /discovery-plan → /prd-draft → /generate-tasks — against a single scenario. Each step's output becomes the next step's input. The scenario is a real Terrain problem: guide activation drop-off. The challenge is to go from raw problem context to a backlog-ready story set in one session.
Individual skills are easy to run in isolation. The harder skill — for both the PM and the agent — is maintaining coherence across a chain. What assumptions from the discovery plan constrain the PRD? What decisions in the PRD surface as story-level ambiguities in the task breakdown? The capstone tests whether those handoffs happen cleanly and whether the agent carries context without the PM having to repeat it.
Day 19 is the first capstone because discovery → spec → tasks is the shorter chain and the workflow PMs run most often. Day 20 is the full strategic cycle, which compounds this chain with alignment and communication. Today is the foundation.