# GPT-5.6 Luna spotted on Arena

GPT-5.6 Luna is a model from OpenAI, released on 9 Jul 2026. First seen 11 Sep 2026. Catalogues list a 1,050,000 tokens context window. 15 evidence links.

- Kind: Sighting
- Developer: OpenAI
- Confidence: Confirmed
- First seen: 2026-09-11T22:09:46.186Z
- Model: [GPT-5.6 Luna](https://alexgetman.com/models/openai/gpt-5-6-luna/)
- Canonical: https://alexgetman.com/signals/2026/09/11/gpt-5-6-luna/

## Evidence links

- [Arena · leaderboards](https://openai.com/index/gpt-5-6/)
- [VoxelBench · leaderboard](https://voxelbench.ai/leaderboard)
- [TrueFoundry · Azure catalogue](https://github.com/truefoundry/models/blob/main/providers/microsoft-foundry/gpt-5.6-luna.yaml)
- [Codex · model list](https://github.com/openai/codex/blob/main/codex-rs/models-manager/models.json)
- [OpenCode · discovery](https://opencode.ai/data/openai/gpt-5-6-luna)
- [OpenRouter](https://openrouter.ai/openai/gpt-5.6-luna-pro)
- [OpenRouter](https://openrouter.ai/openai/gpt-5.6-luna)
- [Artificial Analysis · benchmarks](https://artificialanalysis.ai/models)
- [OpenRouter](https://openrouter.ai/openai/gpt-5.6-luna-pro:batch)
- [OpenRouter](https://openrouter.ai/openai/gpt-5.6-luna:batch)
- [Vercel AI Gateway](https://vercel.com/ai-gateway)
- [OpenAI · pricing](https://developers.openai.com/api/docs/pricing)
- [models.dev · catalogue](https://models.dev/#databricks-gpt-5-6-luna)
- [models.dev · catalogue](https://models.dev/#gpt-5-6-luna)
- [models.dev · catalogue](https://models.dev/#gpt-5.6-luna)