GPT-5.6 Luna vs Grok Build 0.1
| OpenAI GPT-5.6 Luna | xAI Grok Build 0.1 | |
|---|---|---|
| Vendor | OpenAI | xAI |
| Context window | 1,050,000 | 256,000 |
| Max output | 128,000 | — |
| Reasoning | Yes | Yes |
| Tool calling | Yes | Yes |
| File input | Yes | Yes |
| Input | text, image | text, image |
| Output | text | text |
| Released | 2026-07-08 | 2026-05-29 |