GStack
An open-source Claude Code skill set by Gary Tan (President of Y Combinator) that brings YC’s startup-building methodology to solo developers. The goal: give one person the leverage of an entire development team.
What It Is
GStack is not a collection of individual tools — it’s a process. A set of markdown-based prompts that teach Claude Code how to think like different startup roles: CEO, CTO, engineering manager, senior designer, design partner, staff engineer, debugger. Each role gets a dedicated prompt file that focuses the agent on problems through that lens.
The inspiration: Andrej Karpathy saying he hadn’t typed a line of code since December. Gary Tan’s question: “How does one person ship like a team of 20?”
Key Skills
/gstack office-hours— Six forcing questions that reframe your product before writing any code, modeled on actual YC office hours/gstack plan— CEO review: rethink the problem, find the “10-star product” (reference to Airbnb’s Brian Chesky)- Engineering manager, senior designer, design partner, staff engineer, debugger — role-specific analysis prompts for reviewing a codebase through that lens
Installation
One command: copy the install prompt from the GStack docs and paste into Claude Code. It asks a few questions, requests permissions, and installs.
Why It Matters
GStack is prompt engineering as open-source product. Reading the documentation is reading how Gary Tan actually thinks about startups, YC office hours, product-market fit. Because it’s open source, you can inspect and adapt every prompt.
Adoption
~50,000 GitHub stars within two weeks of launch (as of March 2026).
See Also
- Claude Code — the harness GStack is built for
- Superpowers — similar Claude Code skill set, more TDD-focused
- Matthew Berman — source
- Source: Open-Source AI Projects