‘This is absurd’: 22-year-old San Francisco tech founder let AI manage her money — and claims she saved $700 on day one

“All I had to do was give it every bit of data about my life,” Cantillon wrote in The Free Press, describing how the system began building helpers to take on tasks for her.

With access to that information, Cantillon began using Claude to create a network of specialized AI tools that could handle different pieces of her life, from administrative busywork to her finances.

Putting AI to work

Once Cantillon had her digital assistants up and running, she gave Claude a job most people would probably rather avoid themselves: figuring out where her money was disappearing.

It combed through transactions across her credit cards and flagged recurring charges, including gym memberships, Netflix and other subscriptions that are easy to sign up for and even easier to forget about.

“It pulled all of my transactions across all of my credit cards and when it found repetitive subscriptions, it would ask me, “Hey, is this something that you use?” And I would say yes or no,” she wrote.

If the answer was no, Claude would draft an email asking the company to cancel the subscription. The experiment started paying off almost immediately.

“On day one, I got $700 back. This is absurd,” Cantillon wrote.

Considering Claude Code cost her $20 a month, she said the math was pretty easy: the tool had already paid for itself and then some.

That’s one use case where having a digital assistant digging through your finances might actually come in handy.

A 2026 Self Financial survey found nearly 60% of Americans had at least one paid subscription they weren’t using. On average, those forgotten charges were costing them $26.79 a month, more than $320 over the course of a year.

Claude the advisor

Cantillon says Claude now plays a role in managing her personal finances, pulling information from brokerages and scanning everything from company filings and headlines to hedge fund disclosures, Polymarket odds and posts on X.

“My personal finances are now managed by Claude Code,” she wrote. “Overnight it picks the locks of brokerages that refuse to talk to each other.”

By morning, she says Claude has turned all of that information into a personalized portfolio briefing, flagging potential opportunities to buy or sell.

That may sound convenient, but this is also where a wrong answer can get expensive. AI tools can produce inaccurate or misleading information, and Americans are still split on how much they trust them with financial advice.