Claude Opus 5.5
Anthropic's flagship for reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. 1M context, 128K max output, and a lower rack rate than Opus 5.
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Context
1M
Weights
Closed
API only
Input
$4
/1M tok
Output
$20
/1M tok
Cache read
$0.20
0.05x input
Cache write
$5
1.25x input
Pricing via OpenRouter
Reported on 7 evals across 6 domains - best 100.0% on ProofBench · #1 of 62