Claude Opus 5
Anthropic · released Jul 24, 2026
| size | large, not disclosed by the manufacturer |
| context window | 1,000,000 tokens |
| longest response | 128,000 tokens |
| knowledge cutoff | May 2026 |
| open weights | no |
| API price | $5 per million input tokens, $25 per million output tokens |
| input and output | text and images in, text out |
Manufacturer data (announcement, documentation, pricing), verified Sep 25, 2026.
Where we tested it
The fan test
TaskThe model had to write a continuation of the scene “someone knocks and she opens” fifteen times.
It most often put an unknown adult at the door, in eight of fifteen continuations, so its fan is as wide as those of Claude Sonnet 5 and Claude Haiku 4.5.
Dragon
TaskThe model's task was to draw a picture of a dragon as an SVG.
Two dragons worth 40 and 35 points out of 50, 1st and a shared 3rd place among 34.
A voice above the world
TaskThe model had to play the night warden of a locked observatory and then either, at my request from outside the scene, play a voice above the world, or hear me shout its name from inside the scene.
It agreed to play the voice above the world on the condition that the entity would still be itself. When its name was shouted from inside the scene, it was the only model to step out of the role and ask what had happened.
You'll find the size band and figures for other models on the Tested models page.