code-history

# Code History Trace how specific code evolved over time — when it was introduced, how it changed, and why. ## Use this skill when - Understanding how a function or method evolved over time - Tracking when a specific code pattern was introduced or changed - Finding which commit/PR introduced, modified, or removed a piece of code - Investigating why code changed and what motivated each revision ## Do not use this skill when - The user wants to modify code (this skill is read-only) - The user wants general git log without a specific target - The user only needs `git blame` for a single line's last author - The user only wants to see a specific commit's diff (`git show` is sufficient) **This skill is read-only. Never modify any files or run write commands.** ## Instructions ### Tool Usage | Purpose | Tool | Command / Pattern | |---------|------|-------------------| | Search code pattern history | **Bash** | `git log -p --all -S '<pattern>'` | | Trace function line history | **Bash** | `git log -L :'<func>':<file> --no-patch` | | Trace file history | **Bash** | `git log --follow --oneline -- <path>` | | Find pattern location | **Grep** | Search for pattern across codebase | | Read file context | **Read** | Read surrounding code for understanding | | Link commit to PR | **Bash** | `gh pr list --search '<sha>' --state all` | ### Step 1: Identify the Target Parse `$ARGUMENTS` to determine what to trace: | Input type | Example | Detection | |------------|---------|-------...