On August 4, Grant de Swardt, an independent AI consultant in East Sussex, UK, noticed something strange going on with his Claude Max 20x account. He hadn\u2019t been working that day, yet his token usage was climbing.<\/p>\n
The next day, he disabled everything he had attached to Claude and did not work with it. Token consumption again increased. \u201cIn the clearest controlled interval, it increased from 45% to 55% while I performed no work, scheduled Cowork tasks were paused or completed, Dispatch\/cloud execution was disabled, and there was no corresponding active local Claude Code task,\u201d de Swardt told TechCrunch.<\/p>\n
What was eating up his token allowance? He had no idea, so he contacted Anthropic and asked for an itemized list. Anthropic didn\u2019t provide one, but it agreed something was off. It suspended his paid account, invalidated all of his sessions and server-side Claude Code tokens, and issued him a partial refund of \u00a344.49\u00a0for the remaining time on his $200-per-month subscription.<\/p>\n
The suspension wreaked havok on his business, he told TechCrunch. His job is to help small and mid-size businesses set up agents \u2014 a sort of forward-deployed engineer for hire \u2014 for tasks like automatically loading purchase-order data from emails into the accounting software.<\/p>\n
As a sole proprietor, he relies on agents throughout his whole business, too: daily admin tasks, website design, coding. \u201cLike everything is just running through AI these days,\u201d he said.<\/p>\n
After investigating, Anthropic told de Swardt it found the culprit: A compromised Claude session key was used to mint unauthorized Claude Code OAuth tokens. The company told him the account \u201cappeared to have been used by an unauthorized-looking third-party service to handle activity for other people, but they could not determine how it obtained access,\u201d he told TechCrunch. \u201cThey say the evidence is consistent either with credentials\/session data being taken without my knowledge, or with the account having been connected to an outside service.\u201d<\/p>\n
In other words, a hacker was able to obtain access to de Swardt\u2019s account and was covertly siphoning off his tokens. Because account support tracks total usage but not itemized usage, even upon request, this kind of theft could have gone on for months undetected. <\/p>\n
He posted his experience on Reddit<\/a> and after 80 comments, he discovered he was not alone. One person claimed that their account \u201cwas auto-upgraded without my consent, my credit card got charged, and the usage shot from 0% to 100% automatically without me even touching it.\u201d Another saw usage go from 0 to 49% in 12 mins, when all they had used it for was a couple of prompts and a web search.<\/p>\n