Anthropic: 1,000 Claude Fable 5.2 agents reproduce Fermat's Last Theorem formalization in 28.7 hours
7 hours without the Prove2Me platform or researcher steering used in Anthropic's September run, writing a proof one-seventh as long and using one-third as many output tokens. Each agent worked in a network-isolated sandbox with a classifier checking every shell command and file edit plus an offline monitor, and across more than a million tool calls none met the bar to be blocked.
Why it matters: Anthropic's 1,000-agent run reproduced the Fermat's Last Theorem formalization without Prove2Me or a researcher, showing how sandboxing and monitoring bound a self-organized agent team.