Pyyan / Compare / Claude Mythos 5.1 vs GPT-6.1 Sol
Claude Mythos 5.1 vs GPT-6.1 Sol
2 of 5Language Models · verified 1 Oct 2026
Claude Mythos 5.1Anthropiccurrent
GPT-6.1 SolOpenAIcurrent| Specification | Claude Mythos 5.1 | GPT-6.1 Sol |
|---|---|---|
| Summary | Fable 5.1 with the safety classifiers removed. You cannot simply buy it. | Astra's score on DeepSWE, at a fifth of Astra's cost. |
| Context | 1M | 1.05M |
| Input ($/Mtok) | $10 | $2 |
| Output ($/Mtok) | $50 | $10 |
| Licence | Proprietary, gated | Proprietary |
| Max output | 128K | 128K |
| Parameters | Not published | Not published |
| Released | 1 Sep 2026 | 29 Sep 2026 |
| Model ID | claude-mythos-5-1 | gpt-6.1-sol |
| Category | Language Models | Language Models |
| Official | — | OpenAI ↗ |
Highlighted rows are where these differ.
Claude Mythos 5.1
- The same underlying model as Fable 5.1, at a different safeguard level
- US organisations and individuals in Anthropic's trusted access programmes only
- Safety classifiers and high-risk fallbacks removed for Project Glasswing participants
Best for vetted frontier research.
GPT-6.1 Sol
- Matches GPT-6 Astra on DeepSWE v1.1 at roughly a fifth of the cost
- $5.47 per Terminal-Bench Science task against $23.80 for Astra
- Above 272K tokens a prompt bills at 2x input and 1.5x output for the whole request
Best for coding and agent work at volume.