Skill: Codebase Archaeology

Analyze repository history to understand architecture, hotspots, ownership, and risk before major changes.

When to use

1. •New contributor onboarding.
2. •Pre-migration planning.
3. •Before large refactors.

Workflow

1. •Identify hotspots.

git log --pretty=format: --name-only | sort | uniq -c | sort -rn | head -30

1. •Identify ownership and bus factor.

git shortlog -sn
git shortlog -sn -- path/to/file

1. •Trace subsystem evolution.

git log --follow --oneline -- path/to/file
git log --oneline --grep='refactor\|rewrite\|migration\|deprecat'

1. •Map recurring bug zones.

git log --oneline --grep='fix\|bug\|incident\|hotfix' --all | head -80
rg -n 'TODO|FIXME|HACK|XXX' .

Required artifacts

1. •docs/research/codebase-archaeology-report.md with hotspots and risk map.
2. •ADR candidates list for major turning points.
3. •Migration risk notes referenced by ticket IDs.