git-investigate

name	git-investigate
description	Git history investigation. Use when: tracking code changes, finding where bugs were introduced, root cause analysis. Not for: code exploration (use code-explore), issue analysis (use issue-analyze). Output: history trace + root cause report.
allowed-tools	Bash(git:*), Read, Grep, Glob, Agent

Git Investigate Skill

Trigger

• Keywords: code history, git blame, track changes, who wrote this, when was it changed, root cause, code archaeology

When NOT to Use

• Code review (use codex-review)
• Feature development (use feature-dev)
• Just want to read code (use Read directly)

Command

/git-investigate src/service/xxx.ts:123      # Specific line
/git-investigate processToken                 # Function name
/git-investigate "error message"              # Keyword

Workflow

Locate code -> git blame -> find commit -> trace history -> analyze changes -> report

Investigation Framework

Question	Method
Who wrote it?	git blame
When was it changed?	git log --follow
Why was it changed?	commit message + PR
What was missed?	git diff compare original vs problematic version

Common Patterns

Pattern	Symptom	Root Cause
Type removed	Enum value deleted	Assumed no longer needed
Condition simplified	If conditions reduced	Missed during refactoring
Rename	Partially unchanged	Incomplete search-and-replace
Boundary ignored	Only handles main flow	Edge cases not considered

Output

## Git Investigation Report
- **Target**: <file/feature>
- **Timeline**: <commit range>
- **Root cause**: <analysis>
- **Introduced by**: <commit hash + author>

Verification

• Report includes: investigation target, author info, timeline, original vs problematic code
• Root cause has clear analysis
• Fix recommendation is specific and actionable

References

• references/commands.md - Git command reference + report template

Examples

Input: Who changed this line of code?
Action: git blame -> find commit -> trace PR -> output report

Input: When was this bug introduced?
Action: git log -p -S -> locate introduction point -> analyze cause -> output report