THE EVIDENCE LEDGER

What happened: Claude Opus 5.5 introduced?

A new cost-performance claim at the frontier.

When was this milestone recorded?

2026-09-22 · Models.

What is the source?

Company announcement. Last verified: 2026-09-26T00:03:51.103Z.

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.

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