~cytrogen/gstack

ref: 3d901066cdb34602675d41dd70b165a6f1a7347c gstack/retro/SKILL.md -rw-r--r-- 11.5 KiB
3d901066 — Garry Tan Initial release — gstack v0.0.1 a month ago

name: retro version: 1.0.0 description: | Weekly engineering retrospective. Analyzes commit history, work patterns, and code quality metrics with persistent history and trend tracking. allowed-tools:

  • Bash
  • Read
  • Write
  • Glob

#/retro — Weekly Engineering Retrospective

Generates a comprehensive engineering retrospective analyzing commit history, work patterns, and code quality metrics. 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 to ensure we have the latest:

git fetch origin main --quiet

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

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

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

# 3. Commit timestamps for session detection and hourly distribution
#    Use TZ=America/Los_Angeles for Pacific time conversion
TZ=America/Los_Angeles git log origin/main --since="<window>" --format="%at|%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/^/#/'

#Step 2: Compute Metrics

Calculate and present these metrics in a summary table:

Metric Value
Commits to main 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

#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)

If the time window is 14 days or more, split into weekly buckets and show trends:

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

#Step 10: Streak Tracking

Count consecutive days with at least 1 commit to origin/main, going back from today:

# Get 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

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: "Shipping streak: 47 consecutive days"

#Step 11: Load History & Compare

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

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 12: Save Retro History

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

mkdir -p .context/retros

Determine the next sequence number for today (substitute the actual date for $(date +%Y-%m-%d)):

# 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:

{
  "date": "2026-03-08",
  "window": "7d",
  "metrics": {
    "commits": 47,
    "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
  },
  "version_range": ["1.16.0.0", "1.16.1.0"],
  "streak_days": 47,
  "tweetable": "Week of Mar 1: 47 commits, 3.2k LOC, 38% tests, 12 PRs, peak: 10pm"
}

#Step 13: Write the Narrative

Structure the output as:


Tweetable summary (first line, before everything else):

Week of Mar 1: 47 commits, 3.2k LOC, 38% tests, 12 PRs, peak: 10pm | Streak: 47d

#Engineering Retro: [date range]

#Summary Table

(from Step 2)

(from Step 11, loaded before save — skip if first retro)

#Time & Session Patterns

(from Steps 3-4)

Narrative interpreting what the 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
  • How this maps to "CEO who also codes" lifestyle

#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

#Focus & Highlights

(from Step 8)

  • Focus score with interpretation
  • Ship of the week callout

#Top 3 Wins

Identify the 3 highest-impact things shipped in the window. For each:

  • What it was
  • Why it matters (product/architecture impact)
  • What's impressive about the execution

#3 Things to Improve

Specific, actionable, anchored in actual commits. Phrase as "to get even better, you could..."

#3 Habits for Next Week

Small, practical, realistic for a very busy person. Each must be something that takes <5 minutes to adopt.

(if applicable, from Step 9)


#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
  • Keep total output around 2500-3500 words
  • 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