Gstack: AI engineering workflow

This post explains the AI coding workflow of Y Combinator’s CEO — how he uses GStack for ideation, building, and deployment.

What is gstack

gstack is a collection of SKILL.md files that give your AI agents personas for different stages of the software/product development life cycle.

A normal software sprint runs through roughly these stages:

think → plan → design → build → review → test → ship

In gstack, there is a SKILL.md file (often several) for each of these stages. You invoke them to guide your agents toward the goal (generating code, a specification, ideation, etc.).

Some of the skills

Below is a sample of the available skills. Explore the gstack repo to find the full set.

Skill	What it does
`/office-hours`	Starting point. Reframes your product idea before you write code.
`/plan-ceo-review`	CEO-level review: find the 10-star product in the request.
`/plan-eng-review`	Lock architecture, data flow, edge cases, and tests.
`/plan-design-review`	Rate each design dimension 0–10, explain what a 10 looks like.
`/plan-devex-review`	DX-mode review: TTHW, magical moments, friction points, persona traces.
`/plan-tune`	Self-tune `AskUserQuestion` sensitivity per question.
`/autoplan`	One command runs CEO → design → eng → DX review.
`/design-consultation`	Build a complete design system from scratch.
`/spec`	Turn vague intent into a precise, executable spec in five phases. Files a GitHub issue, optionally spawns a Claude Code agent in a fresh worktree, and lets `/ship` close the source issue on merge.

Setup

Installation

Clone gstack into your Claude skills directory and run the setup script:

git clone --single-branch --depth 1 https://github.com/garrytan/gstack.git ~/.claude/skills/gstack \
  && cd ~/.claude/skills/gstack \
  && ./setup

Then add a gstack section to your CLAUDE.md that:

tells the agent to use the /browse skill for all web browsing (never the mcp__claude-in-chrome__* tools), and
lists the available skills so the agent knows what it can call: /office-hours, /plan-ceo-review, /plan-eng-review, /plan-design-review, /design-consultation, /design-shotgun, /design-html, /review, /ship, /land-and-deploy, /canary, /benchmark, /browse, /connect-chrome, /qa, /qa-only, /design-review, /setup-browser-cookies, /setup-deploy, /setup-gbrain, /retro, /investigate, /document-release, /document-generate, /codex, /cso, /autoplan, /plan-devex-review, /devex-review, /careful, /freeze, /guard, /unfreeze, /gstack-upgrade, /learn.

Optionally, add gstack to the current project too, so teammates get it.

Quick start

Install gstack (30 seconds — see above).
Run /office-hours — describe what you’re building.
Run /plan-ceo-review on any feature idea.
Run /review on any branch with changes.
Run /qa on your staging URL.
Stop there. You’ll know if this is for you.

/office-hours is where you begin. Before you write any code, it acts as a structured brainstorming partner that helps you upgrade and revise your idea — honing it toward the real problem, testing feasibility, and surfacing what might work and what won’t. It adapts to your context — a startup concept or a side project — and works through several phases. For example, /office-hours asks you several questions that depend on your product: who said this software/product/idea is interesting? Is it a commercial, learning, or entrepreneurship project? It even searches the web to find relevant competitors and identify your differentiator. Based on your answers, it then suggests a couple of points worth noting and considering. By answering those questions, your agent can construct better context for later stages in the pipeline and development.

Alternatives

Superpowers is basically the same idea; we review it in another post.