---

name: decision-archaeology description: Investigate why code was written a certain way. Use when tracing decision history through git blame, commit logs, PRs, and issues to understand the reasoning behind code changes. allowed-tools:

• Bash(git log:*)
• Bash(git show:*)
• Bash(git blame:*)
• Bash(git diff:*)
• Bash(gh pr list:*)
• Bash(gh pr view:*)
• Bash(gh issue list:*)
• Bash(gh issue view:*)
• Bash(gh search:*)
• Bash(gh api:*)
• Read
• Grep
• Glob

---

Decision Archaeology Skill

Rules

Read-only operations only. For gh api: GET requests only. No -X POST/PUT/PATCH/DELETE or -f/-F flags.

Workflow

1. Identify code - Target file, lines, or function
2. Find commit - git blame → introducing commit
3. Trace PR/Issue - Check commit message for #123 references
4. Summarize rationale - Output findings

For detailed commands: See references/commands.md

Key Commands

Copygit blame -L <start>,<end> <file>    # Find who changed lines
git log -S "code" --oneline          # Find when code was added
gh pr list --search "<sha>" --state all  # Find PR for commit

Output Format

Copy## Decision Archaeology Report

### Target
- File: [path/to/file]
- Lines: [XX-YY]

### Timeline

#### [Date] Commit: [short-sha]
- Author: [name]
- Message: [commit message]
- PR: #[number] [title]
- Related Issue: #[number]

### Decision Rationale
[Summary of why, based on PR discussions, issue context, commit messages]

### Key References
- PR #[number]: [URL]
- Issue #[number]: [URL]
- Commit: [sha]

Tips

• Start with git blame to find introducing commit
• Check commit message for #123 references
• PR descriptions and review comments contain the "why"