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
Price & speed via Artificial Analysis · ranked across tracked models · caching via OpenRouter
| Reasoning effort | Index | Speed |
|---|---|---|
| max | 59.1 | 95 t/s |
| xhigh | 57.4 | 81 t/s |
| high | 51.8 | 75 t/s |
| medium | 48.2 | 74 t/s |
| low | 34.8 | 76 t/s |
Intelligence Index per reasoning-effort setting, via Artificial Analysis · pricing identical across tiers
Reported on 14 evals across 9 domains - best 100.0% on ProofBench · #1 of 78
Reported eval scores
14MedScribe91.4
MedCode49.8
SciCode66.9
GPQA Diamond90.6
SAGE91.3
ProofBench100
Vals Index70.2
EQ-Bench 41339.5