Garry Tan, the renowned CEO of Y Combinator, revealed to an audience at SXSW that he is experiencing “cyber psychosis” and is getting minimal sleep due to his excitement over working with AI agents.
In a Saturday interview with fellow venture capitalist Bill Gurley, Tan explained, “I sleep, like, four hours a night right now. I have cyber psychosis, but I think a third of the CEOs that I know have it as well,” he joked, hinting at his intense focus on AI. (Hopefully, he was joking, as AI-induced psychosis is a serious issue.)
He recounted his past experiences, saying, “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,” referencing a popular drug in startup culture. (Tan’s blogging startup, Posterous, supported by Y Combinator, was sold to Twitter in 2012.)
Now, his enthusiasm for AI agents is so intense that it naturally keeps him awake. “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.,” he stated. “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.”
On March 12, just two days before his interview, Tan eagerly shared his Claude Code (CC) setup on GitHub under an open-source license, which included six “opinionated” Claude Code skills. These skills are reusable prompts in “skill.md” files guiding AI on specific roles or tasks.
Expressing his enthusiasm, Tan posted on X, “I’ve been having such an amazing time with Claude Code, I wanted you to be able to have my *exact* skill setup.” He named this setup “gstack.”
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Since then, he has added several more skills, with the gstack GitHub repository now listing 13. Tan appears to tweet about new developments almost hourly.
In a demonstration of his setup, Tan explained how he uses Claude to evaluate startup ideas or features through a skill where Claude acts as a CEO. Other skills enable Claude to write features as an engineer, review its code for bugs and security issues, and manage design and documentation.
The reception for gstack was immediate and enthusiastic: Tan’s tweet went viral on X and trended on Product Hunt. It has garnered nearly 20,000 stars on GitHub and 2,200 forks, indicating widespread interest in modifying the files.
However, Tan also faced criticism after releasing gstack. A tweet claiming a CTO friend described gstack as “god mode” for identifying a security flaw led to some backlash.
Negative reactions included a founder’s comment on X, saying, “(1) Garry should be embarrassed for tweeting this. (2) If it’s true, that CTO should be fired immediately.”
Vlogger Mo Bitar critiqued gstack in a video titled “AI is making CEOs delusional,” emphasizing that the project was simply “a bunch of prompts” in a text file, echoing a common critique that developers using Claude Code already have similar setups.
A Product Hunt user added, “Garry, let’s be clear and honest: if you weren’t the CEO of YC, this wouldn’t be on PH.”
To determine the real value of gstack, expert opinions were sought, including those from Claude, which unsurprisingly praised it. ChatGPT and Gemini also responded positively.
ChatGPT described gstack as having “reasonably sophisticated prompt workflows, but they’re not ‘magical,’” highlighting that AI coding is most effective when simulating an engineering organizational structure rather than simply asking to build a feature.
Gemini referred to the setup as “sophisticated,” noting that “gstack is essentially a ‘Pro’ configuration, focusing more on correctness than ease.”
Claude lauded gstack as “a mature, opinionated system built by someone who actually uses it heavily,” calling it one of the best examples of Claude Code skill design.
On Monday, Tan elaborated in another X post, “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.”
Tan did not respond to multiple requests for comment.
