gstack/retro/SKILL.md

---
name: retro
version: 2.0.0
description: |
  Weekly engineering retrospective. Analyzes commit history, work patterns,
  and code quality metrics with persistent history and trend tracking.
  Team-aware: breaks down per-person contributions with praise and growth areas.
allowed-tools:
  - Bash
  - Read
  - Write
  - Glob
---

# /retro — Weekly Engineering Retrospective

Generates a comprehensive engineering retrospective analyzing commit history, work patterns, and code quality metrics. Team-aware: identifies the user running the command, then analyzes every contributor with per-person praise and growth opportunities. Designed for a senior IC/CTO-level builder using Claude Code as a force multiplier.

## User-invocable
When the user types `/retro`, run this skill.

## Arguments
- `/retro` — default: last 7 days
- `/retro 24h` — last 24 hours
- `/retro 14d` — last 14 days
- `/retro 30d` — last 30 days
- `/retro compare` — compare current window vs prior same-length window
- `/retro compare 14d` — compare with explicit window

## Instructions

Parse the argument to determine the time window. Default to 7 days if no argument given. Use `--since="N days ago"`, `--since="N hours ago"`, or `--since="N weeks ago"` (for `w` units) for git log queries. All times should be reported in **Pacific time** (use `TZ=America/Los_Angeles` when converting timestamps).

**Argument validation:** If the argument doesn't match a number followed by `d`, `h`, or `w`, the word `compare`, or `compare` followed by a number and `d`/`h`/`w`, show this usage and stop:
```
Usage: /retro [window]
  /retro              — last 7 days (default)
  /retro 24h          — last 24 hours
  /retro 14d          — last 14 days
  /retro 30d          — last 30 days
  /retro compare      — compare this period vs prior period
  /retro compare 14d  — compare with explicit window
```

### Step 1: Gather Raw Data

First, fetch origin and identify the current user:
```bash
git fetch origin main --quiet
# Identify who is running the retro
git config user.name
git config user.email
```

The name returned by `git config user.name` is **"you"** — the person reading this retro. All other authors are teammates. Use this to orient the narrative: "your" commits vs teammate contributions.

Run ALL of these git commands in parallel (they are independent):

```bash
# 1. All commits in window with timestamps, subject, hash, AUTHOR, files changed, insertions, deletions
git log origin/main --since="<window>" --format="%H|%aN|%ae|%ai|%s" --shortstat

# 2. Per-commit test vs total LOC breakdown with author
#    Each commit block starts with COMMIT:<hash>|<author>, followed by numstat lines.
#    Separate test files (matching test/|spec/|__tests__/) from production files.
git log origin/main --since="<window>" --format="COMMIT:%H|%aN" --numstat

# 3. Commit timestamps for session detection and hourly distribution (with author)
#    Use TZ=America/Los_Angeles for Pacific time conversion
TZ=America/Los_Angeles git log origin/main --since="<window>" --format="%at|%aN|%ai|%s" | sort -n

# 4. Files most frequently changed (hotspot analysis)
git log origin/main --since="<window>" --format="" --name-only | grep -v '^$' | sort | uniq -c | sort -rn

# 5. PR numbers from commit messages (extract #NNN patterns)
git log origin/main --since="<window>" --format="%s" | grep -oE '#[0-9]+' | sed 's/^#//' | sort -n | uniq | sed 's/^/#/'

# 6. Per-author file hotspots (who touches what)
git log origin/main --since="<window>" --format="AUTHOR:%aN" --name-only

# 7. Per-author commit counts (quick summary)
git shortlog origin/main --since="<window>" -sn --no-merges

# 8. Greptile triage history (if available)
cat ~/.gstack/greptile-history.md 2>/dev/null || true
```

### Step 2: Compute Metrics

Calculate and present these metrics in a summary table:

| Metric | Value |
|--------|-------|
| Commits to main | N |
| Contributors | N |
| PRs merged | N |
| Total insertions | N |
| Total deletions | N |
| Net LOC added | N |
| Test LOC (insertions) | N |
| Test LOC ratio | N% |
| Version range | vX.Y.Z.W → vX.Y.Z.W |
| Active days | N |
| Detected sessions | N |
| Avg LOC/session-hour | N |
| Greptile signal | N% (Y catches, Z FPs) |

Then show a **per-author leaderboard** immediately below:

```
Contributor         Commits   +/-          Top area
You (garry)              32   +2400/-300   browse/
alice                    12   +800/-150    app/services/
bob                       3   +120/-40     tests/
```

Sort by commits descending. The current user (from `git config user.name`) always appears first, labeled "You (name)".

**Greptile signal (if history exists):** Read `~/.gstack/greptile-history.md` (fetched in Step 1, command 8). Filter entries within the retro time window by date. Count entries by type: `fix`, `fp`, `already-fixed`. Compute signal ratio: `(fix + already-fixed) / (fix + already-fixed + fp)`. If no entries exist in the window or the file doesn't exist, skip the Greptile metric row. Skip unparseable lines silently.

### Step 3: Commit Time Distribution

Show hourly histogram in Pacific time using bar chart:

```
Hour  Commits  ████████████████
 00:    4      ████
 07:    5      █████
 ...
```

Identify and call out:
- Peak hours
- Dead zones
- Whether pattern is bimodal (morning/evening) or continuous
- Late-night coding clusters (after 10pm)

### Step 4: Work Session Detection

Detect sessions using **45-minute gap** threshold between consecutive commits. For each session report:
- Start/end time (Pacific)
- Number of commits
- Duration in minutes

Classify sessions:
- **Deep sessions** (50+ min)
- **Medium sessions** (20-50 min)
- **Micro sessions** (<20 min, typically single-commit fire-and-forget)

Calculate:
- Total active coding time (sum of session durations)
- Average session length
- LOC per hour of active time

### Step 5: Commit Type Breakdown

Categorize by conventional commit prefix (feat/fix/refactor/test/chore/docs). Show as percentage bar:

```
feat:     20  (40%)  ████████████████████
fix:      27  (54%)  ███████████████████████████
refactor:  2  ( 4%)  ██
```

Flag if fix ratio exceeds 50% — this signals a "ship fast, fix fast" pattern that may indicate review gaps.

### Step 6: Hotspot Analysis

Show top 10 most-changed files. Flag:
- Files changed 5+ times (churn hotspots)
- Test files vs production files in the hotspot list
- VERSION/CHANGELOG frequency (version discipline indicator)

### Step 7: PR Size Distribution

From commit diffs, estimate PR sizes and bucket them:
- **Small** (<100 LOC)
- **Medium** (100-500 LOC)
- **Large** (500-1500 LOC)
- **XL** (1500+ LOC) — flag these with file counts

### Step 8: Focus Score + Ship of the Week

**Focus score:** Calculate the percentage of commits touching the single most-changed top-level directory (e.g., `app/services/`, `app/views/`). Higher score = deeper focused work. Lower score = scattered context-switching. Report as: "Focus score: 62% (app/services/)"

**Ship of the week:** Auto-identify the single highest-LOC PR in the window. Highlight it:
- PR number and title
- LOC changed
- Why it matters (infer from commit messages and files touched)

### Step 9: Team Member Analysis

For each contributor (including the current user), compute:

1. **Commits and LOC** — total commits, insertions, deletions, net LOC
2. **Areas of focus** — which directories/files they touched most (top 3)
3. **Commit type mix** — their personal feat/fix/refactor/test breakdown
4. **Session patterns** — when they code (their peak hours), session count
5. **Test discipline** — their personal test LOC ratio
6. **Biggest ship** — their single highest-impact commit or PR in the window

**For the current user ("You"):** This section gets the deepest treatment. Include all the detail from the solo retro — session analysis, time patterns, focus score. Frame it in first person: "Your peak hours...", "Your biggest ship..."

**For each teammate:** Write 2-3 sentences covering what they worked on and their pattern. Then:

- **Praise** (1-2 specific things): Anchor in actual commits. Not "great work" — say exactly what was good. Examples: "Shipped the entire auth middleware rewrite in 3 focused sessions with 45% test coverage", "Every PR under 200 LOC — disciplined decomposition."
- **Opportunity for growth** (1 specific thing): Frame as a leveling-up suggestion, not criticism. Anchor in actual data. Examples: "Test ratio was 12% this week — adding test coverage to the payment module before it gets more complex would pay off", "5 fix commits on the same file suggest the original PR could have used a review pass."

**If only one contributor (solo repo):** Skip the team breakdown and proceed as before — the retro is personal.

**If there are Co-Authored-By trailers:** Parse `Co-Authored-By:` lines in commit messages. Credit those authors for the commit alongside the primary author. Note AI co-authors (e.g., `noreply@anthropic.com`) but do not include them as team members — instead, track "AI-assisted commits" as a separate metric.

### Step 10: Week-over-Week Trends (if window >= 14d)

If the time window is 14 days or more, split into weekly buckets and show trends:
- Commits per week (total and per-author)
- LOC per week
- Test ratio per week
- Fix ratio per week
- Session count per week

### Step 11: Streak Tracking

Count consecutive days with at least 1 commit to origin/main, going back from today. Track both team streak and personal streak:

```bash
# Team streak: all unique commit dates (Pacific time) — no hard cutoff
TZ=America/Los_Angeles git log origin/main --format="%ad" --date=format:"%Y-%m-%d" | sort -u

# Personal streak: only the current user's commits
TZ=America/Los_Angeles git log origin/main --author="<user_name>" --format="%ad" --date=format:"%Y-%m-%d" | sort -u
```

Count backward from today — how many consecutive days have at least one commit? This queries the full history so streaks of any length are reported accurately. Display both:
- "Team shipping streak: 47 consecutive days"
- "Your shipping streak: 32 consecutive days"

### Step 12: Load History & Compare

Before saving the new snapshot, check for prior retro history:

```bash
ls -t .context/retros/*.json 2>/dev/null
```

**If prior retros exist:** Load the most recent one using the Read tool. Calculate deltas for key metrics and include a **Trends vs Last Retro** section:
```
                    Last        Now         Delta
Test ratio:         22%    →    41%         ↑19pp
Sessions:           10     →    14          ↑4
LOC/hour:           200    →    350         ↑75%
Fix ratio:          54%    →    30%         ↓24pp (improving)
Commits:            32     →    47          ↑47%
Deep sessions:      3      →    5           ↑2
```

**If no prior retros exist:** Skip the comparison section and append: "First retro recorded — run again next week to see trends."

### Step 13: Save Retro History

After computing all metrics (including streak) and loading any prior history for comparison, save a JSON snapshot:

```bash
mkdir -p .context/retros
```

Determine the next sequence number for today (substitute the actual date for `$(date +%Y-%m-%d)`):
```bash
# Count existing retros for today to get next sequence number
today=$(TZ=America/Los_Angeles date +%Y-%m-%d)
existing=$(ls .context/retros/${today}-*.json 2>/dev/null | wc -l | tr -d ' ')
next=$((existing + 1))
# Save as .context/retros/${today}-${next}.json
```

Use the Write tool to save the JSON file with this schema:
```json
{
  "date": "2026-03-08",
  "window": "7d",
  "metrics": {
    "commits": 47,
    "contributors": 3,
    "prs_merged": 12,
    "insertions": 3200,
    "deletions": 800,
    "net_loc": 2400,
    "test_loc": 1300,
    "test_ratio": 0.41,
    "active_days": 6,
    "sessions": 14,
    "deep_sessions": 5,
    "avg_session_minutes": 42,
    "loc_per_session_hour": 350,
    "feat_pct": 0.40,
    "fix_pct": 0.30,
    "peak_hour": 22,
    "ai_assisted_commits": 32
  },
  "authors": {
    "Garry Tan": { "commits": 32, "insertions": 2400, "deletions": 300, "test_ratio": 0.41, "top_area": "browse/" },
    "Alice": { "commits": 12, "insertions": 800, "deletions": 150, "test_ratio": 0.35, "top_area": "app/services/" }
  },
  "version_range": ["1.16.0.0", "1.16.1.0"],
  "streak_days": 47,
  "tweetable": "Week of Mar 1: 47 commits (3 contributors), 3.2k LOC, 38% tests, 12 PRs, peak: 10pm",
  "greptile": {
    "fixes": 3,
    "fps": 1,
    "already_fixed": 2,
    "signal_pct": 83
  }
}
```

**Note:** Only include the `greptile` field if `~/.gstack/greptile-history.md` exists and has entries within the time window. If no history data is available, omit the field entirely.

### Step 14: Write the Narrative

Structure the output as:

---

**Tweetable summary** (first line, before everything else):
```
Week of Mar 1: 47 commits (3 contributors), 3.2k LOC, 38% tests, 12 PRs, peak: 10pm | Streak: 47d
```

## Engineering Retro: [date range]

### Summary Table
(from Step 2)

### Trends vs Last Retro
(from Step 11, loaded before save — skip if first retro)

### Time & Session Patterns
(from Steps 3-4)

Narrative interpreting what the team-wide patterns mean:
- When the most productive hours are and what drives them
- Whether sessions are getting longer or shorter over time
- Estimated hours per day of active coding (team aggregate)
- Notable patterns: do team members code at the same time or in shifts?

### Shipping Velocity
(from Steps 5-7)

Narrative covering:
- Commit type mix and what it reveals
- PR size discipline (are PRs staying small?)
- Fix-chain detection (sequences of fix commits on the same subsystem)
- Version bump discipline

### Code Quality Signals
- Test LOC ratio trend
- Hotspot analysis (are the same files churning?)
- Any XL PRs that should have been split
- Greptile signal ratio and trend (if history exists): "Greptile: X% signal (Y valid catches, Z false positives)"

### Focus & Highlights
(from Step 8)
- Focus score with interpretation
- Ship of the week callout

### Your Week (personal deep-dive)
(from Step 9, for the current user only)

This is the section the user cares most about. Include:
- Their personal commit count, LOC, test ratio
- Their session patterns and peak hours
- Their focus areas
- Their biggest ship
- **What you did well** (2-3 specific things anchored in commits)
- **Where to level up** (1-2 specific, actionable suggestions)

### Team Breakdown
(from Step 9, for each teammate — skip if solo repo)

For each teammate (sorted by commits descending), write a section:

#### [Name]
- **What they shipped**: 2-3 sentences on their contributions, areas of focus, and commit patterns
- **Praise**: 1-2 specific things they did well, anchored in actual commits. Be genuine — what would you actually say in a 1:1? Examples:
  - "Cleaned up the entire auth module in 3 small, reviewable PRs — textbook decomposition"
  - "Added integration tests for every new endpoint, not just happy paths"
  - "Fixed the N+1 query that was causing 2s load times on the dashboard"
- **Opportunity for growth**: 1 specific, constructive suggestion. Frame as investment, not criticism. Examples:
  - "Test coverage on the payment module is at 8% — worth investing in before the next feature lands on top of it"
  - "3 of the 5 PRs were 800+ LOC — breaking these up would catch issues earlier and make review easier"
  - "All commits land between 1-4am — sustainable pace matters for code quality long-term"

**AI collaboration note:** If many commits have `Co-Authored-By` AI trailers (e.g., Claude, Copilot), note the AI-assisted commit percentage as a team metric. Frame it neutrally — "N% of commits were AI-assisted" — without judgment.

### Top 3 Team Wins
Identify the 3 highest-impact things shipped in the window across the whole team. For each:
- What it was
- Who shipped it
- Why it matters (product/architecture impact)

### 3 Things to Improve
Specific, actionable, anchored in actual commits. Mix personal and team-level suggestions. Phrase as "to get even better, the team could..."

### 3 Habits for Next Week
Small, practical, realistic. Each must be something that takes <5 minutes to adopt. At least one should be team-oriented (e.g., "review each other's PRs same-day").

### Week-over-Week Trends
(if applicable, from Step 10)

---

## Compare Mode

When the user runs `/retro compare` (or `/retro compare 14d`):

1. Compute metrics for the current window (default 7d) using `--since="7 days ago"`
2. Compute metrics for the immediately prior same-length window using both `--since` and `--until` to avoid overlap (e.g., `--since="14 days ago" --until="7 days ago"` for a 7d window)
3. Show a side-by-side comparison table with deltas and arrows
4. Write a brief narrative highlighting the biggest improvements and regressions
5. Save only the current-window snapshot to `.context/retros/` (same as a normal retro run); do **not** persist the prior-window metrics.

## Tone

- Encouraging but candid, no coddling
- Specific and concrete — always anchor in actual commits/code
- Skip generic praise ("great job!") — say exactly what was good and why
- Frame improvements as leveling up, not criticism
- **Praise should feel like something you'd actually say in a 1:1** — specific, earned, genuine
- **Growth suggestions should feel like investment advice** — "this is worth your time because..." not "you failed at..."
- Never compare teammates against each other negatively. Each person's section stands on its own.
- Keep total output around 3000-4500 words (slightly longer to accommodate team sections)
- Use markdown tables and code blocks for data, prose for narrative
- Output directly to the conversation — do NOT write to filesystem (except the `.context/retros/` JSON snapshot)

## Important Rules

- ALL narrative output goes directly to the user in the conversation. The ONLY file written is the `.context/retros/` JSON snapshot.
- Use `origin/main` for all git queries (not local main which may be stale)
- Convert all timestamps to Pacific time for display (use `TZ=America/Los_Angeles`)
- If the window has zero commits, say so and suggest a different window
- Round LOC/hour to nearest 50
- Treat merge commits as PR boundaries
- Do not read CLAUDE.md or other docs — this skill is self-contained
- On first run (no prior retros), skip comparison sections gracefully