# gpt-5.5-high

Claude Opus 4.8 is a model from Anthropic, released on 28 May 2026. First seen 13 Sep 2026. Catalogues list a 1,000,000 tokens context window. 9 evidence links.

- Kind: Sighting
- Developer: Anthropic
- Confidence: Confirmed
- First seen: 2026-09-13T22:35:52.903Z
- Model: [Claude Opus 4.8](https://alexgetman.com/models/anthropic/claude-opus-4-8/)
- Canonical: https://alexgetman.com/signals/2026/09/13/gpt-5-5-high-6/

## Evidence links

- [Arena · leaderboards](https://www.anthropic.com/news/claude-opus-4-8)
- [VoxelBench · leaderboard](https://voxelbench.ai/leaderboard)
- [models.dev · catalogue](https://models.dev/#claude-opus-4-8)
- [OpenCode · discovery](https://opencode.ai/data/anthropic/claude-opus-4-8)
- [Artificial Analysis · benchmarks](https://artificialanalysis.ai/models)
- [OpenRouter](https://openrouter.ai/anthropic/claude-opus-4.8)
- [Vercel AI Gateway](https://vercel.com/ai-gateway)
- [models.dev · catalogue](https://models.dev/#claude-opus-4.8)
- [Claude Code · model ids](https://www.npmjs.com/package/@anthropic-ai/claude-code/v/2.1.317)