GStack: Turn Claude Code Into a Full Engineering Team
Max QuimbyGarry Tan's gstack gives Claude Code 23 specialist skills: CEO, Eng Manager, QA. 82K stars and still climbing. Here's what actually works.
The first time you type /office-hours into Claude Code with GStack installed, something strange happens. The AI stops acting like a helpful coding assistant and starts acting like a skeptical product manager who thinks your feature idea is probably wrong.
That is the design. And it is why GStack — Garry Tan's open-source Claude Code skill setup — has accumulated 82,700 stars and 12,000 forks on GitHub since its March 2026 launch.
For context: Garry Tan is the President and CEO of Y Combinator. When the person who has reviewed more startups than almost anyone else on earth open-sources the exact AI development workflow that runs his code, developers pay attention. They also argue about it extensively on Hacker News.
This guide explains what GStack actually does, how it compares to oh-my-openagent and other harnesses, why the "it's just prompts" criticism misses the point, and whether it belongs in your workflow.
What GStack Actually Does: The 23 Skills
GStack is not a new coding assistant. It is a collection of CLAUDE.md skills — structured instructions that give Claude Code specialist personas. Install it in your project, and Claude Code gains access to 23 tools that simulate an engineering team.
The roles divide into recognizable job functions:
Planning and Strategy
-
/office-hours— Product interrogation with forcing questions. Challenges your idea before you build it. The "skeptical PM" experience. -
/plan-ceo-review— Strategic scope challenge. Asks whether you are solving the right problem. -
/plan-eng-review— Architecture and testing challenge. Finds the assumptions in your technical plan. -
/plan-design-review— Design system audit. Catches "AI slop" — visual patterns that look fine locally but break at scale. -
/plan-devex-review— Developer experience review of the plan. -
/autoplan— Runs CEO, Engineering, and DevEx review in sequence automatically.
Design and Implementation
-
/design-consultation,/design-shotgun,/design-html— Design guidance at various fidelity levels. -
/review— Code review targeting security issues, bugs, and architectural concerns. -
/investigate— Root-cause debugging with structured reasoning.
Testing and Quality
-
/qa— Live browser testing with fixes applied inline. -
/qa-only— Bug reporting without code modification. -
/cso— Security audit applying OWASP Top 10 and STRIDE threat modeling.
Release and Deployment
-
/ship,/land-and-deploy,/document-release
Additional Tools
-
/browse,/canary,/benchmark,/retro,/codex,/pair-agent,/learn
The /codex skill adds OpenAI Codex as a parallel review engine inside Claude Code, giving you cross-model code review without leaving your terminal.
The Conductor: Parallelizing Everything
The Conductor coordinates multiple Claude Code sessions running simultaneously in isolated workspaces. One session running /office-hours on a new idea, another doing /review on an open PR, a third implementing a feature, a fourth running /qa on staging — each in its own git worktree with its own context window.
This is the part that makes GStack genuinely novel compared to a folder of CLAUDE.md prompts. Conductor is multi-agent orchestration built into the harness — not a separate tool you have to wire up yourself.
The Productivity Claim: 810×
Garry Tan reports his 2026 development pace at approximately 810× his 2013 baseline (11,417 logical lines/day vs 14). Key caveats:
The metric is "logical LOC," not raw lines. Logical LOC measures meaningful changes — new behaviors, not reformatted whitespace. This is a more honest metric than it first appears.
The 2013 baseline is a single-developer comparison. Tan is comparing his own pre-AI vs. post-AI productivity. Not a controlled experiment, but an honest data point.
It doesn't hold for all workflows. The TechCrunch analysis notes developers working on hardware-adjacent code or regulated domains see much smaller gains.
The "Just Prompts" Criticism
The most common dismissal: GStack is "a bunch of prompts in a text file." This criticism is partially correct and mostly misses the point.
It is correct that the individual skills are structured prompts. There's no compiled code, nothing that prevents you from reading every CLAUDE.md instruction.
What the criticism misses is that the value is in the system design, not the technology. The insight is architectural: separating planning from implementation, using adversarial reviewing roles, and enforcing security audits as a default step before shipping. These are software engineering principles applied to AI agent orchestration.
The CTO testimonial Garry Tan shared is worth taking at face value:
A security audit that runs automatically before every merge is not "just a prompt." It is a default gate that most teams skip under schedule pressure. GStack makes skipping it harder than doing it.
GStack vs the Field
| GStack | oh-my-openagent | GSD | cc-switch | |
|---|---|---|---|---|
| Stars | 82.7K | 53.9K | 35K | 54K |
| Model lock-in | Claude Code only | Multi-model | Claude Code first | Model-agnostic config |
| Specialist roles | 23 skills | 11 agents | Spec-driven only | None |
| Parallel sessions | Yes (Conductor) | Yes | No | No |
| Install complexity | 30 seconds (paste) | npm install | Manual | CLI install |
oh-my-openagent routes tasks to the best model — if you need DeepSeek for cost-sensitive tasks and Claude for hard reasoning, OmO handles the routing. GStack is entirely Claude Code native.
When GStack Wins, When It Doesn't
GStack is best for:
- Solo developers building SaaS or web products without a senior team
- Early-stage startups without dedicated QA, security reviewer, or architect
- Developers already on Claude Code — zero-friction install
- Teams shipping fast who default to skipping review steps
GStack is probably wrong for:
- Teams needing multi-model routing (OmO is better)
- Teams with mature code review culture (GStack replaces informal processes)
- Developers on OpenCode or non-Claude agents (CLAUDE.md-native)
- Embedded, firmware, or highly regulated domains
Getting Started in 30 Seconds
GStack lives at github.com/garrytan/gstack. Install: open Claude Code and type Install GStack.
Your first three commands:
-
/office-hours— Challenge your current feature idea -
/cso— Security audit on your last commit -
/autoplan— CEO, Eng, and DevEx review your next technical plan
The Bottom Line
GStack implements software engineering best practices — adversarial review, security auditing, design critique, spec challenge — as default steps in your Claude Code workflow. Steps that solo developers skip not because they are bad engineers but because there is nobody else in the room.
If you are a Claude Code user building a product, install it. The 30-second install cost is trivially small relative to finding a single XSS vulnerability before it ships to production.
The frontier in AI-assisted development is not a better autocomplete. It is a well-designed team of reviewers who catch the mistakes you were going to make anyway.
Originally published at AgentConn