Seductive. Intoxicating. All-consuming. These aren't descriptions of romantic love or illicit drugs-they're how startup founders talk about managing their newest employees: AI agents.

Aditya Sharma recently went to bed at 6 a.m. after an all-nighter with his crew of generative-AI bots-systems that plan and execute multistep tasks like pulling data and writing code.

He's the co-founder of Keel, which makes artificial-intelligence troubleshooting software for IT teams. The agents are building new customer features, conducting research for an in-house model and monitoring marketing campaigns.

But because agents often require guidance or additional context as they move through their tasks, Sharma, 27, finds himself wanting to be available to them around the clock and forgoing a regular sleep schedule as a result. Until recently, he couldn't monitor them remotely through a phone or smartwatch.

"The cost of the agents' being blocked for eight hours is way too high," he says. "They can be done with their work at any point of time, in the middle of the night."

Founders have long put in punishing hours in the name of building the next big thing. But the growing capabilities of AI agents-and the speed at which the models powering them are evolving-give new meaning to working yourself to the bone.

The more work AI agents do, the more founders find themselves working. Add to that the pressure of what many view as a once-in-humanity moment in technology and you get erratic sleep schedules, a struggle to focus on anything but work, and the feeling that even though the pace isn't healthy or sustainable, you just can't stop.

Sharma, who lives in San Francisco, has put on more weight in recent months. And while he doesn't like to admit it, he finds it more difficult to be present with others outside of working hours because of his agents.

"They just demand your attention," he says. "Does it need anything? Can I help it in any way?"

Peter Pezaris, 56, promised his wife he would retire this year after more than 30 years in the tech industry and four successful exits. As a young founder, he was hospitalized twice during punishing work stretches. He once slept an hour a night for a month straight before collapsing at the office.

"A lot of people exaggerate the 9-9-6," he says, referring to founders who post online about working 9 a.m. to 9 p.m., six days a week. "I lived this when there wasn't a way to brag about it."

Yet the allure of the AI boom and the "intoxicating nature" of the latest AI tools proved too strong to resist. Four months ago, he launched a fifth startup, Proxon, to make AI workforce-management software. He estimates it will have an annual revenue run rate of more than $1 million by October.

"It's like a drug," Pezaris says of working with AI agents. "I've never actually done drugs but I imagine it's what it feels like."

Pezaris, who lives in San Mateo, Calif., typically works from 7:30 a.m. to 2 a.m. He estimates Proxon, which employs six human developers, is operating 30 times faster than it would without agents. But agent work begets human work: Onboarding customers at a faster clip means needing to respond to more customer requests, for example.

There's also an agent FOMO multiplier effect. "Every minute that I'm not working, I'm missing out on not doing a week's worth of work," says Pezaris.

Abby Grills, co-founder of AI-enabled data-gathering platform Riveter, feels like there's always more she can be doing and every hour she works can make or break her company. She and her co-founder, Cody Watters, are the only two employees. The pair keeps planning to hire-but then find they're able to tackle yet another task with agents.

"We think we can do it, just the two of us," she says.

Grills, who is 33 and lives in San Francisco, typically works 10 hours a day and takes one weekend day off. She went through the Y Combinator startup accelerator program in 2024 and saw firsthand the effects of pushing too hard. A fellow founder in her cohort was hospitalized after failing to eat solid foods and living off mostly meal-replacement products. (Y Combinator says it has long advocated that its founders take care of themselves.)

Grills is aware that without proper sleep and some semblance of a life outside of work, her output will inevitably suffer.

"I'm exhausted all the time, don't get me wrong," she says. Nonetheless, "we're a little bit more careful about taking rest when we need it."

Ajay Kalia, 43 and a Boston-based AI startup founder, says he first knew AI was going to upend the world back in February 2023 while working at Spotify's AI group. He witnessed people with doctorate degrees and 20 years of experience coming out of rooms with their faces sagging.

"They were saying these really strange things like, 'My Ph.D. is useless,'" he says.

Having left Spotify in 2024 to launch his own company, Alt, Kalia now starts most days at 5:30 or 6 a.m., wrapping up around 9 or 10 p.m. He uses agents, but every few months has to recalibrate his work around their rapidly evolving capabilities.

"You can build these bigger and wildly more ambitious concepts with these new models, which is fantastic," he says, "except you're never done."

Kalia recently started controlling agents from his Apple Watch, which is proving to be a blessing and a curse. His watch buzzes every 10 minutes with another agent request.

"I don't know if it's healthy for me to be out on a run looking at my watch to give my agent permission to do something," he says.

No one in Kalia's extended founder network has considered taking time off or expressed concerns about burnout, though he sees many seemingly teetering on the edge.

"Everybody just acknowledges quietly to each other that, on the one hand, it's unsustainable but, on the other hand, why would you stop?" he says.