git-mining

name	git-mining
description	This skill should be used when the user asks to "check git history", "trace code changes", "find when something was added", "correlate commits with sessions", "find hotspot files", or needs to mine git repository history for insights. Only applicable when the current project is a git repository.
version	0.1.0

Git Mining — Code History Integration

Prerequisite Check

Before using git commands, verify the project is a git repo:

git rev-parse --git-dir 2>/dev/null && echo "IS_GIT_REPO" || echo "NOT_GIT_REPO"

If not a git repo, skip all git-related analysis and rely on JSONL data only.

Scripts

Cluster commits into work sessions

bash ${CLAUDE_PLUGIN_ROOT}/scripts/git-sessions.sh [repo-path] [--since "14 days ago"] [--gap 3600]

Full structured context dump

bash ${CLAUDE_PLUGIN_ROOT}/scripts/git-context.sh [repo-path] [--since "7 days ago"] [--limit 30]

Key Git Commands for Agents

Recent commits with file changes

git log --pretty=format:"%h|%ai|%s" --numstat --since="14 days ago" -30

File history (survives renames)

git log --oneline --follow -- path/to/file.ts

Symbol archaeology (when was X introduced?)

git log --oneline -S "FunctionName"        # exact string
git log --oneline -G "pattern.*regex"      # regex in diff

Hotspot files (most frequently changed)

git log --name-only --pretty=format: --since="30 days ago" | grep -v '^$' | sort | uniq -c | sort -rn | head -15

Commit message search

git log --oneline --grep="keyword" -i

What changed in a file recently

git log -p --follow --since="7 days ago" -- path/to/file.ts

Correlating Git Commits with Claude Sessions

Git commits made during Claude Code sessions cluster together in time (typically 60-440 seconds apart). Cross-session gaps are 1+ hours.

Method 1: Timestamp matching

Compare sessions-index.json entries (created/modified fields) with git commit timestamps (git log --pretty=format:"%at") to find which commits were made during which sessions.

Method 2: Conventional commit patterns

Claude Code sessions typically produce commit sequences like:

• feat: → fix: → fix: → docs: → release: (complete cycle)
• fix: → test: (debugging session)
• refactor: → style: (cleanup session)

Method 3: Branch correlation

The gitBranch field in session records and sessions-index.json entries tells you which branch each session was working on. Match with git log --all --oneline <branch>.

What to Extract from Git History

Question	Command
What changed recently?	git log --oneline --since="7 days ago"
What files change together?	git log --name-only then co-occurrence analysis
Who/what introduced a bug?	git log -S "buggy_code" + git blame
What's the architectural evolution?	git log --diff-filter=A --name-status (new files over time)
What keeps breaking?	git log --grep="fix" --name-status
What was the rationale?	git log --pretty=format:"%s%n%b" -1 <hash> (commit body)

Combining Git + JSONL

The most powerful analysis combines both sources:

1. Find the relevant git commits for a time period
2. Match their timestamps to Claude sessions
3. Read the session .jsonl to understand the full conversation context behind those commits
4. This gives you: what was done (git) + why it was done (conversation) + what was tried and failed (tool errors in JSONL)