THE FRONTIER SIGNALSTHE EVIDENCE LEDGER
What happened: METR publishes Opus 5.5 assessment?
Preliminary independent evaluation reports incremental AI R&D capability gains, with access and disclosure limitations.
When was this milestone recorded?
2026-09-22 · Evaluation.
What is the source?
METR: predeployment evaluation of Claude Opus 5.5 ↗
Independent evaluation; unpaid access agreement and provider text review disclosed. Last verified: 2026-09-26T20:03:37.888Z.
What does this tell us about the pace of AI?
This is one selected milestone. Its inclusion does not establish a change in capability, economic returns or an industry-wide growth rate. Announcement, release and measurement dates are different concepts.