The discovery began with a human‑written brief asking agents to find new reverse‑transcriptase systems through previously unknown partner‑gene associations. Anthropic's harness split that job into tasks, pairing a Claude Code worker that proposed and ran an analysis with a supervising agent that reviewed the plan and results. Agents could open follow‑up work and wrote their output to a shared record. Their endpoint was a set of reports for human reviewers.
Running Claude Mythos 5, the campaign searched a database containing about 1.9 billion protein clusters. It recovered roughly 200,000 reverse‑transcriptase clusters, sampled about 11,000 loci and scored 3,564 recurring neighboring protein families. Sixteen candidate families passed the campaign's filters, and an agent‑generated follow‑up added a seventeenth. The complete run comprised 119 tasks, 949 agent sessions, 215.6 million tokens and 21.5 hours of wall‑clock time. The paper calls this period free of human intervention, which applies to the campaign after researchers supplied its brief, harness and data rather than to the project as a whole.
Most promoted candidates did not survive review. Three of the 17 candidate partner families were retained as previously unreported associations; the other 14 were rejected or set aside. ART emerged from a side path rather than the partner‑family ranking itself. A worker rejected one apparent neighboring‑gene association, opened a closer look at the reverse transcriptase, read the raw upstream DNA and recognized the tandem repeats. It counted the repeats, compared the layout with known systems and searched the literature before filing a report for people to assess.
That division of labor matters when describing autonomous discovery. The agent made the anomalous observation and pursued it computationally. People defined the broad question, built the environment, selected work for follow‑up and performed every laboratory experiment. The evidence supports AI‑directed anomaly detection inside a bounded research system; it does not describe an AI independently choosing a field, acquiring samples or operating a lab.