Gary, president and CEO of Y Combinator, introduces **GStack**—an open‑source “thin‑harness, fat‑skills” framework that turns AI code‑generation models into a coordinated engineering team with defined roles, processes, and review steps. Using GStack’s **office‑hours** skill, he walks through refining a startup idea (a tool that pulls 1099 tax documents from Gmail and bank portals), runs an adversarial review to strengthen the design, and then employs the **design‑shotgun** tool to generate UI options. The framework also includes browser‑automation, QA, and shipping tools that let agents perform end‑to‑end software development—from planning and coding to testing and PR submission—dramatically accelerating his own workflow (he reports coding more in two months than in all of 2013). GStack is available on GitHub, and Gary encourages developers to leverage this new “agent era” to build useful software quickly.
1. Gary is president and CEO of Y Combinator.
2. Gary is an engineer.
3. Gary spent the first decade of his career building software full‑time.
4. Gary studied computer systems engineering at Stanford.
5. Gary was employee number 10 at Palunteer.
6. At Palunteer, Gary worked as an engineer, designer, and product manager.
7. Gary co‑founded Posterous, a microblogging platform that was sold to Twitter.
8. Gary built the first version of Bookface, Y Combinator’s internal social platform and knowledge base.
9. Gary has written code throughout his career.
10. Gary says we are in a completely new era of building software called the agent era.
11. Gary built GStack three weeks ago.
12. GStack now has more GitHub stars than Ruby on Rails.
13. GStack is an open‑source repository.
14. GStack turns clawed code into an AI engineering team for the user.
15. Office hours is a skill in GStack modeled after Y Combinator partner office hours with startups.
16. Office hours begins by asking six forcing questions to reframe the product before building.
17. The best way to get started with GStack is via Conductor.
18. GStack is built into Conductor.
19. In the demo, GStack is used to create a tax app that extracts 1099s from Gmail.
20. The tax app searches the user’s inbox and accepts URLs to download 1099 PDFs from financial institutions.
21. GStack browser style lets the user log in, then AI navigates to tax docs and downloads PDFs while the user watches.
22. The adversarial review improved the design doc score from 6 out of 10 to 8 out of 10 with three remaining issues.
23. The adversarial review automatically caught and fixed 16 issues.
24. Design shotgun generated three UI options: command center, friendly progress, and split view.
25. Option B (friendly progress) was selected for the tax app UI.
26. GStack has more than 70,000 GitHub stars.
27. Users of cloud code spend 80% to 90% of their time in office hours, plan CEO review, and auto plan.
28. Gary wrote a CLI around Playwright and Chromium, providing a headed and headless browser in GStack.
29. The CLI enables agents to use the browser, take screenshots, click, fill forms, download media, run regression tests, update CSS, and assess real browser bugs.
30. GStack includes a ship tool to verify PR readiness before landing on main.
31. Gary runs 10 to 15 parallel Claude Code sessions simultaneously.
32. Gary has multiple open‑source projects with tens of thousands of stars.
33. Gary currently has about 400 pull requests to review.
34. GStack is available at github.com/gritan/GStack.