Research Git Patterns

When to Use

INVOKE when user asks about:

How a feature was implemented
Finding similar code patterns
Understanding implementation history
Retrieving story context

Git Commands for Story Retrieval

Find All Commits for a Story

# Get full implementation history
git log --grep="US-001-auth-login-admin" --oneline --graph

# Get detailed changes with code
git log --grep="US-001-auth-login-admin" -p --follow

# Get just the files changed
git diff --name-only main...$(git log --grep="US-001-auth-login-admin" -1 --format=%H)

Analyze Implementation Patterns

# Find similar authentication implementations
git log --grep="auth\|login\|clerk" --oneline

# See how rate limiting was implemented across stories
git log -S"RateLimiter" -p

# Find all FastAPI endpoint additions
git log --diff-filter=A -- "apps/server/src/api/**/*.py"

Extract Story Context

# Get story implementation timeline
git log --grep="US-001-auth-login-admin" --format="%ai %s" | sort

# Calculate implementation time
git log --grep="US-001-auth-login-admin" --format="%at" | awk 'NR==1{first=$1} END{print (last-first)/3600 " hours"}'

# Get test coverage evolution
git log --grep="US-001-auth-login-admin" --format="%h" | xargs -I {} sh -c 'git show {}:coverage.json 2>/dev/null | jq .total'

Build Complete Context

# Create story summary
story="US-001-auth-login-admin"
echo "=== Story $story Implementation ==="
echo "\n📝 Commits:"
git log --grep="$story" --oneline

echo "\n📁 Files Modified:"
git diff --name-status main...$(git log --grep="$story" -1 --format=%H)

echo "\n✅ Tests Added:"
git diff main...$(git log --grep="$story" -1 --format=%H) -- "*test*.py" --name-only

echo "\n📊 Statistics:"
git log --grep="$story" --shortstat | grep -E "files? changed"

Pattern Mining

Find Reusable Patterns

# Example: Find all endpoint security patterns
patterns = {
    "auth": "git log -S'@router.post.*Depends.*get_current_user' -p",
    "rate_limit": "git log -S'RateLimiter' -p",
    "validation": "git log -S'@validator' -p",
    "error_handling": "git log -S'HTTPException' -p"
}

Generate Implementation Template

# Extract common backend structure from story
git show --format="" --name-only $(git log --grep="US-001-auth-login-admin" --format=%H) |
  grep "apps/server" |
  sed 's|apps/server/||' |
  sort -u

Context Building for Claude

When building context from git:

Start with story commits
```
git log --grep="US-XXX" --oneline
```
Get implementation details
```
git show <commit-hash>
```
Find related patterns
```
git log -S"<key-concept>" --oneline
```
Build file history
```
git log --follow -p -- <file-path>
```

Integration with User Stories

The minimal user story files reference git commits. Use these commands to expand context:

# From user story: "Implementation: git log --grep='US-001-auth-login-admin'"
# Expand to full context:
git log --grep="US-001-auth-login-admin" --stat --format=fuller

Efficiency Tips

Use git aliases for common patterns:

git config --global alias.story 'log --grep'
git config --global alias.pattern 'log -S'

Cache results in Memory MCP:
- Story implementation summaries
- Common patterns
- Reusable code blocks

Batch operations for multiple stories:

for story in US-001-auth-login-admin US-002 US-003; do
  echo "=== $story ==="
  git log --grep="$story" --oneline
done

Error Recovery

If git history is unclear:

Check commit message conventions
Use broader search patterns
Fallback to file-based search
Ask user for clarification

Performance Metrics

Git operations are typically:

git log --grep: <100ms
git show: <50ms per commit
git diff: <200ms for feature branch
Full story context: <2 seconds

Compare to file reading:

Multiple file reads: 500ms-2s
Context building: 2-5s
Pattern searching: 1-3s

Git approach is 3-5x faster for context retrieval