What problem does it solve? Keeping documentation for vendored or mirrored upstream projects current is tedious: you must detect whether the upstream changed, diff commits, and rewrite architecture notes by hand. This Skill automates that research loop and produces four consistent documents per project. ## Core Features & Use Cases - Mode-gated sync: Compares the upstream git HEAD against the recorded last_synced_hash to choose FULL, DIFF, FULL_NO_GIT, or SKIP modes, with rollback warnings and --force / --no-git-check overrides. - Four-file documentation output: Writes architecture.md, changelog.md, sync.json, and extend.md under docs/upstream/<project>/, with incremental changelog prepending for DIFF runs. - User-controlled rules: An extend.md file with protected USER_RULES and auto-regenerated AI_SUGGESTIONS sections lets users steer focus areas without losing customizations. - Use Case: After pulling new commits into upstream/some-lib, run the research flow to get an updated changelog of interface changes and a refreshed architecture overview without reading every diff manually. ## Quick Start Ask the assistant to research the upstream project named my-lib and update its documentation under docs/upstream.
