What problem does it solve? When multiple agents ship app changes, knowledge about obstacles, fixes, and lessons learned gets lost between sessions. This Skill enforces a mandatory append-only change log so every agent can read what previous agents shipped, what blocked them, and what golden tips they left behind. ## Core Features & Use Cases - Structured log appends: Record app_id, agent, summary, obstacles, fixes, golden tips, and touched paths into a shared JSON log via a single CLI command. - Read-before-edit queries: List all logged apps or fetch the full history for a specific app before making changes. - UI ledger integration: Optionally append a parallel UI upgrade ledger entry when a change modifies the interface. - Use Case: After fixing an e2e failure in the mac_health app, an agent appends an entry describing the blocker and fix, so the next agent working on mac_health sees the context immediately. ## Quick Start Append a change log entry for the app you just modified by running the hub_pro_skills_v1.py script with your agent id, summary, obstacles, and fixes.