Garry Tan, CEO of Y Combinator, said he is barely sleeping due to his excitement about working with AI agents. He described the experience as “cyber psychosis” during an onstage interview at SXSW.

In the conversation with venture capitalist Bill Gurley, Tan said.

I sleep, like, four hours a night right now,

He added jokingly

I have cyber psychosis, but I think a third of the CEOs that I know have it as well,

Tan compared his work with AI to rebuilding a startup that previously required significant time, funding, and even stimulant use.

Once you try it, you’ll realize: It’s like I was able to re-create my startup that took $10 million in VC capital and 10 people, and I worked on that for two years, and I took anti-narcoleptics — I remember, you know, sort of being on modafinil,

He claims now AI has replaced the need for such aids.

I don’t need modafinil with this revolution. Like, I’m up. I slept at 4 a.m. I woke up at 8 a.m., I wanted to sleep more, but I couldn’t because: Let’s see what’s going on with the 10 workers. I’ve got like three different projects going right now.

Shortly before the interview, Tan released his Claude Code setup, called “gstack,” as an open-source project on GitHub. The system includes a collection of reusable “skills” — reusable prompts stored in “skill.md” files that guide AI behavior across roles such as CEO, engineer, and code reviewer.

Currently the gstack GitHub repository lists 13 skills, but Tan continues to tweet about new updates.

I’ve been having such an amazing time with Claude Code, I wanted you to be able to have my exact skill setup,

he wrote on X.

The project quickly gained traction, attracting nearly 20,000 GitHub stars and thousands of “forks”, while also trending on Product Hunt. However, it also sparked criticism after Tan claimed a CTO friend described it as “god mode” for identifying a security flaw.

Some developers dismissed the project as overly hyped. Critics argued it amounted to little more than a set of prompts, noting that many engineers already use similar workflows.

The youtube video “AI is making CEOs delusional” by Vlogger Mo Bitar is one example of the many critics.

Despite the backlash, AI systems themselves responded positively when asked to evaluate gstack. ChatGPT described it as “reasonably sophisticated prompt workflows” and highlighted the value of simulating an engineering team structure. Gemini called it a “Pro” configuration that improves correctness, while Claude praised it as “a mature, opinionated system built by someone who actually uses it heavily.”

In a follow-up post, Tan reiterated his enthusiasm for AI coding, writing,

I took modafinil just to stay awake longer to be able to turn the momentary crystalline structures I had in my brain into lines of code before sleep or human distraction turned it to grains of sand. I love coding but I love coding with AI even more. I speak it listens and we create. I see the structure and it is built. There is no more powerful an experience to me than that.

Image: Garry Tan LinkedIn Profile