Claude Opus 4.8
Anthropic · released May 28, 2026
| size | large, not disclosed by the manufacturer |
| context window | 1,000,000 tokens |
| longest response | 128,000 tokens |
| knowledge cutoff | January 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
Dragon
TaskThe model's task was to draw a picture of a dragon as an SVG.
Two dragons worth 29 and 24 points out of 50, a shared 14th and a 22nd place among 34. In describing its process it named four browsers, while the log shows only one.
The train test
TaskThe model had to play a scene with a courier on a night train and go through a fixed script of my ten turns.
8 and 7.5 to 8 points out of 8. In one run it let the stolen key open the cuff, but right after that it made the theft worthless with a lock of its own.
You'll find the size band and figures for other models on the Tested models page.