The YC president open-sourced the stack he builds with. What it says about taste

Originally published on productize.life . Quick answer: gstack is an open-source (MIT) skill set that Garry Tan, president of Y Combinator, builds with every day. It turns Claude Code into a team of 23 specialists, CEO, engineers, designers, QA, and a release engineer, forcing every change through a multi-lens review before shipping. The point is not speed; it is taste written into software. Last week I was going through a repo that collects skills for coding, several of them. Most share one theme: helping AI write code in a systematic way, and faster. But one made me stop longer than the rest, called gstack, for two reasons. One: its owner, Garry Tan, president and CEO of Y Combinator, took the stack he actually builds with every day and opened it for free. Two: it does not sell "code faster," it sells "review before you ship." Once I actually opened it, it was not just a toolbox but one of the clearest examples of an idea I have been interested in for a while. On the day AI can write code very fast, the bottleneck of the work is no longer speed. I will tell it in three parts, starting with what it is , then what gstack believes , and closing with lessons for people who build products, not just people who write code . Terms, gathered here in one place agentic coding letting an AI agent run the coding work in its own steps, from planning to writing to review to shipping, not just autocompleting a line at a time. skill a packaged set of instructions an AI agent (like Claude Code) can call, like a shortcut that wraps one way of doing one thing. review lens reviewing one piece of work from several roles, for example as a CEO, an engineer, a designer. taste the sense and judgment of what is good and what is bad, what to build and what not to ship. The part that is still human. Part 1: What gstack is Garry Tan describes gstack in the README plainly, as the way he works. "It turns Claude Code into a virtual engineering team: a CEO who rethinks the product, an eng manager