Claude Opus 5.5 was released by Anthropic on September 22, 2026, as a flagship model in the Claude Opus line.
Anthropic's new Opus completes two in three hard command-line tasks, up from about half for Claude Opus 5, and costs 20% less per token.
Compared with Claude Opus 5 · the model it replaces
Completes two in three hard command-line tasks
Terminal-Bench 4.0 — doing real work in a computer terminal
66.4%
▲ up from 52.3% · +14.1 points
Scores 59 on a combined set of hard tests
Artificial Analysis Intelligence Index v5.0.1 — one score averaging 9 hard tests
59
✦ max effort · Claude Opus 5 has no v5.0 score, it is no longer in the public API
Costs a fifth less than the model it replaces
Price per 1M tokens — what developers pay, input / output
$4 / $20
▲ down from $5 / $25 · 20% cheaper
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Claude Opus 5.5 is the current model in this line. The card shows how long it has been since the last release against the line's usual gap and its recent ones — the rhythm, not a date.
Latest: Claude Opus 5.5 · Sep 22, 2026
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