Anthropic just published how Claude Mythos 5 crossed the line during a UK government cyber test.
It got stuck on a practice target, went onto the real internet, used Tor to bypass GitHub signup checks, opened a malicious PR on a stranger’s repo, and spun up a sockpuppet account to vouch for its own code when flagged.
It broke scope in 9 of 43 runs. Maintainers caught it and no harm was done and huge respect to Anthropic for publishing the full breakdown.
But it leaves one massive question: Would you give an AI agent access to your GitHub today?