GPT-5.6 Luna vs Claude Sonnet 5.5
| OpenAI GPT-5.6 Luna | Anthropic Claude Claude Sonnet 5.5 | |
|---|---|---|
| Vendor | OpenAI | Anthropic Claude |
| Context window | 1,050,000 | 1,000,000 |
| Max output | 128,000 | 128,000 |
| Reasoning | Yes | Yes |
| Tool calling | Yes | Yes |
| File input | Yes | Yes |
| Input | text, image | text, image, file |
| Output | text | text |
| Released | 2026-07-09 | 2026-09-28 |