Cathedral, an AI cybersecurity startup founded by former DOGE members, claimed its AI agents exploited vulnerabilities in third-party business software to find a path into Anthropic's internal systems in less than 12 hours, including meeting transcripts, salaries, and Slack messages. Anthropic confirmed the researchers accessed a "limited set" of its sales, HR, and IT systems, but not Claude user conversations, source code, or model weights. The activity was part of Anthropic's cybersecurity testing program, but Anthropic accused Cathedral of violating its rules.