J Stack

6 cognitive modes for the full development lifecycle. Plan like a founder, architect like a tech lead, build with TDD discipline, review like a staff engineer, iterate like Karpathy, ship like a release engineer.

Inspired by obra/superpowers, garrytan/gstack, and karpathy/autoresearch.

  /plan ──→ /architect ──→ /tdd ──→ /review ──→ /ship
                                      ↑
                          /iterate ────┘

The Modes

Mode	Role	What It Does
/plan	Founder/CEO	10-star product thinking. Explore approaches, scope, and design before code.
/architect	Tech Lead	Mermaid diagrams, interface contracts, edge case tables, ADRs.
/tdd	Disciplined Engineer	Strict RED→GREEN→REFACTOR. No production code without a failing test.
/review	Staff Engineer	Two-pass review: critical safety issues first, informational quality second.
/iterate	Autonomous Researcher	Karpathy-style loop: goal → metric → modify → verify → keep/revert → repeat.
/ship	Release Engineer	Sync, test, build, lint, diff review, PR, CI verification.
/jstack	Orchestrator	Shows all modes, suggests the natural next step.

Install

For Claude Code

git clone https://github.com/YOUR_USERNAME/jstack.git ~/.claude/skills/jstack
cd ~/.claude/skills/jstack && ./setup

For Craft Agent

git clone https://github.com/YOUR_USERNAME/jstack.git /tmp/jstack
cd /tmp/jstack && ./setup --craft-agent

Manual Install

Copy each skill folder into your skills directory:

# Claude Code
cp -r plan architect tdd review iterate ship jstack ~/.claude/skills/

# Craft Agent
cp -r plan architect tdd review iterate ship jstack ~/.craft-agent/workspaces/my-workspace/skills/

Usage

Full Pipeline (New Features)

Go through the modes in order for substantial new work:

1. /plan — What to build? Use the 10-star framework to find the insight, then scope to shippable.
2. /architect — How to build it? Diagrams, contracts, edge cases. No hand-waving.
3. /tdd — Build it test-first. Every RED→GREEN→REFACTOR cycle gets a commit.
4. /review — Two-pass audit. Critical safety first, then quality.
5. /ship — Sync, test, build, PR, verify CI.

Direct Mode (Specific Tasks)

Jump to any mode when context is clear:

• Bug report → /tdd (reproduce with a failing test, then fix)
• PR ready → /review then /ship
• Performance problem → /iterate (set metric, loop)
• Technical decision → /architect
• New project → /plan

Autonomous Optimization

/iterate runs independently for any measurable metric:

Goal: Increase test coverage from 72% to 90%
Metric: coverage %
Verify: npm test -- --coverage | grep 'All files'
Guard: npm test (all tests still pass)

Then it loops: modify → verify → keep/revert → repeat until you interrupt.

Philosophy

From Superpowers (obra)

• Design before code. Brainstorming is mandatory, even for "simple" tasks.
• TDD is non-negotiable. If you didn't watch the test fail, you don't know if it tests the right thing.
• Evidence over claims. Systematic verification at every step.

From Gstack (Garry Tan)

• Explicit cognitive modes. No "mushy middle" — each phase has its own mindset.
• Paranoid review. Find the bugs that survive CI but break at 3 AM.
• Ship is a discipline. The last mile deserves as much rigor as the first.

From Autoresearch (Karpathy)

• Goal + Metric + Loop. Any measurable outcome can be optimized autonomously.
• One change per iteration. Atomic = attributable.
• Simplicity wins. 50 lines > 200 lines.

Structure

jstack/
├── README.md
├── LICENSE
├── setup
├── jstack/
│   ├── SKILL.md          # Orchestrator — the meta-skill
│   └── icon.svg
├── plan/
│   ├── SKILL.md          # Founder Mode
│   └── icon.svg
├── architect/
│   ├── SKILL.md          # Tech Lead Mode
│   └── icon.svg
├── tdd/
│   ├── SKILL.md          # Red-Green-Refactor
│   └── icon.svg
├── review/
│   ├── SKILL.md          # Staff Engineer Mode
│   └── icon.svg
├── iterate/
│   ├── SKILL.md          # Karpathy Loop
│   └── icon.svg
└── ship/
    ├── SKILL.md          # Release Engineer Mode
    └── icon.svg

License

MIT