propagate-design-change

# Propagate Design Change When a GDD changes, architectural decisions written against it may no longer be valid. This skill finds every affected ADR, compares what the ADR assumed against what the GDD now says, and guides the user through resolution. **Usage:** `/propagate-design-change design/gdd/combat-system.md` --- ## 1. Validate Argument A GDD path argument is **required**. If missing, fail with: > "Usage: `/propagate-design-change design/gdd/[system].md` > Provide the path to the GDD that was changed." Verify the file exists. If not, fail with: > "[path] not found. Check the path and try again." --- ## 2. Read the Changed GDD Read the current GDD in full. --- ## 3. Read the Previous Version Run git to get the previous committed version: ```bash git show HEAD:design/gdd/[filename].md ``` If the file has no git history (new file), report: > "No previous version in git — this appears to be a new GDD, not a revision. > Nothing to propagate." If git returns the previous version, do a conceptual diff: - Identify sections that changed (new rules, removed rules, modified formulas, changed acceptance criteria, changed tuning knobs) - Identify sections that are unchanged - Produce a change summary: ``` ## Change Summary: [GDD filename] Date of revision: [today] Changed sections: - [Section name]: [what changed — new rule, removed rule, formula modified, etc.] Unchanged sections: - [Section name] Key changes affecting architecture: - [Change 1 — likely to affe...