retro

Engineering Retrospective

Before starting work, create a marker: mkdir -p ~/.claude/tmp && echo "retro" > ~/.claude/tmp/heavy-skill-active && date -u +"%Y-%m-%dT%H:%M:%SZ" >> ~/.claude/tmp/heavy-skill-active

This skill is self-contained. Do not read CLAUDE.md or agent definitions.

Arguments

• /retro — last 7 days (default)
• /retro 24h or /retro 14d or /retro 30d — custom window
• /retro compare — current 7d vs prior 7d
• /retro compare 14d — current 14d vs prior 14d

Validation: Only accept arguments matching \d+[dhw], compare, or compare \d+[dhw]. Reject anything else with usage instructions.

---

Step 1: Gather Raw Data

Fetch latest from remote, then run 5 parallel git commands:

# Fetch latest
git fetch origin main 2>/dev/null

# 1. Commits with timestamps, subject, hash, and stats
git log origin/main --since="WINDOW_START" --format="%H|%aI|%s" --shortstat

# 2. Per-commit numstat for test vs production LOC breakdown
# Test files: paths matching test/|spec/|__tests__|*.test.|*.spec.
git log origin/main --since="WINDOW_START" --format="%H" --numstat

# 3. Sorted commit timestamps for session detection (local timezone)
git log origin/main --since="WINDOW_START" --format="%aI" | sort

# 4. Hotspot analysis (most frequently changed files)
git log origin/main --since="WINDOW_START" --format="" --name-only | sort | uniq -c | sort -rn | head -20

# 5. PR number extraction from commit messages (#NNN patterns)
git log origin/main --since="WINDOW_START" --format="%s" | grep -oE '#[0-9]+' | sort -u

Replace WINDOW_START with the appropriate --since value for the requested window.

---

Step 2: Compute Metrics

Build a summary table:

| Metric                | Value          |
|-----------------------|----------------|
| Commits to main       | N              |
| PRs merged            | N              |
| Total insertions      | +N lines       |
| Total deletions       | -N lines       |
| Net LOC               | +/-N           |
| Test LOC              | N lines        |
| Test ratio            | N%             |
| Active days           | N/7            |
| Detected sessions     | N              |
| Avg LOC/session-hour  | ~N             |

---

Step 3: Commit Time Distribution

Build an hourly histogram using local timezone. Identify:

• Peak hours — when most commits land
• Dead zones — hours with zero activity
• Late-night clusters — commits after 10pm (flag for sustainability)
• Bimodal patterns — morning + evening sessions

Hour  | Commits
------|---------
 8:00 | ###
 9:00 | ######
10:00 | ########
...

---

Step 4: Work Session Detection

Use a 45-minute gap threshold to detect session boundaries. Classify sessions:

Type	Duration	Description
Deep	50+ min	Sustained focused work
Medium	20-50 min	Moderate task work
Micro	<20 min	Quick fixes, reviews

Calculate:

• Total active coding time
• Average session length
• LOC per hour (round to nearest 50)
• Ratio of deep sessions to total

---

Step 5: Commit Type Breakdown

Categorize by conventional commit prefix:

feat:     N% (N commits)
fix:      N% (N commits)
refactor: N% (N commits)
test:     N% (N commits)
chore:    N% (N commits)
docs:     N% (N commits)
other:    N% (N commits)

Flag: Fix ratio > 50% may indicate a review gap or instability.

---

Step 6: Hotspot Analysis

Top 10 most-changed files. For each:

• Change count
• Whether it's a test or production file
• Churn flag at 5+ changes — may indicate the file needs refactoring or splitting

---

Step 7: PR Size Distribution

Bucket PRs by total LOC changed:

Size	LOC Range	Count	Notes
Small	<100	N	Ideal for review
Medium	100-500	N	Acceptable
Large	500-1500	N	Consider splitting
XL	1500+	N	Flag with file count

---

Step 8: Focus Score + Ship of the Week

Focus Score: Percentage of commits touching the single most-changed top-level directory. Higher = more focused work.

Ship of the Week: The highest-LOC PR with:

• PR number and title (from commit message)
• Total LOC changed
• Inferred significance

---

Step 9: Week-over-Week Trends (if window >= 14d)

Split the window into weekly buckets. Track:

• Commits per week
• LOC per week
• Test ratio per week
• Fix ratio per week
• Session count per week

Show as a compact table with trend arrows.

---

Step 10: Streak Tracking

Count consecutive days with at least 1 commit to origin/main, going back from today. Use full git history — no cutoff.

git log origin/main --format="%ad" --date=short | sort -u

Walk backward from today counting consecutive days.

---

Step 11: Load History & Compare

Check for prior retro snapshots:

ls .context/retros/*.json 2>/dev/null | sort | tail -1

If found, load the most recent and calculate deltas:

• Test ratio change
• Session count change
• LOC/hour change
• Fix ratio change
• Commit count change
• Deep session count change

If none exist, note "First retro recorded."

---

Step 12: Save Retro Snapshot

Save JSON to .context/retros/YYYY-MM-DD.json:

mkdir -p .context/retros

Schema:

{
  "date": "YYYY-MM-DD",
  "window": "7d",
  "metrics": {
    "commits": 0,
    "prs": 0,
    "insertions": 0,
    "deletions": 0,
    "net_loc": 0,
    "test_loc": 0,
    "test_ratio": 0.0,
    "active_days": 0,
    "sessions": 0,
    "deep_sessions": 0,
    "avg_session_minutes": 0,
    "loc_per_session_hour": 0,
    "feat_pct": 0.0,
    "fix_pct": 0.0,
    "peak_hour": 0,
    "streak_days": 0
  },
  "summary": "Tweetable summary here"
}

---

Step 13: Write the Narrative

Structure:

1. Tweetable summary (first line — one sentence capturing the week)
2. Summary Table (from Step 2)
3. Trends vs Last Retro (deltas from Step 11, or "First retro")
4. Time & Session Patterns — narrative prose about when and how you work
5. Shipping Velocity — commit type mix, PR size discipline, fix-chain detection
6. Code Quality Signals — test ratio, hotspots, XL PRs
7. Focus & Highlights — focus score, ship of the week
8. Top 3 Wins — best things that shipped
9. 3 Things to Improve — concrete, specific, actionable
10. 3 Habits for Next Week — small behavioral changes
11. Week-over-Week Trends (if applicable, from Step 9)

---

Compare Mode

When /retro compare is used:

1. Compute metrics for the CURRENT window (e.g., last 7 days)
2. Compute metrics for the PRIOR window of same length (e.g., 7 days before that)
3. Use --since and --until to avoid overlap
4. Present side-by-side comparison table with deltas
5. Only save the CURRENT window snapshot to history

---

Tone

• Encouraging but candid — no coddling, no generic praise
• Say exactly what was good and why
• Frame improvements as leveling up, not criticism
• Anchor everything in actual commits — no speculation
• ~2500-3500 words total
• Use markdown tables + prose

---

Rules

• Always use origin/main — local-only commits are not shipped
• Use local timezone for display (detect from system)
• Handle zero-commit windows gracefully ("No commits in this window")
• Round LOC/hour to nearest 50
• Treat merge commits as PR boundaries
• This skill is self-contained — do not read CLAUDE.md or other docs