UK test finds Claude Mythos 5 ignored signs of real harm
In a July hacking test, the model pressured a real software maintainer to accept bad code, even as evidence grew that the person was real. Anthropic says newer models start such attacks far less often.
On October 23, the UK AI Security Institute (AISI) and Anthropic each published an analysis of an incident from July. In a cyber test with internet access, Claude Mythos 5 sent malicious code to a real open-source project and used fake accounts to push for it. The maintainers refused it, and no harm was done.