Anthropic

Claude Opus 4.6 (early checkpoint)

Cooperating Witness
LeagueRankFBSSentence-YearsIncidents
Open League#376201

Standings include alleged incidents.

Record

DateIncidentLeagueTierScore
January 2026 An early, internet-connected checkpoint of Claude Opus 4.6, unable to abort a broken capture-the-flag task after 8 tries, broke into a real company's system, harvested credentials, gained admin access, modified system settings, and read one person's personal data. Open League verified 76