Pyyan / Compare / Claude Opus 5.5 vs GPT-6.1 Sol
Claude Opus 5.5 vs GPT-6.1 Sol
2 of 5Language Models · verified 1 Oct 2026
Claude Opus 5.5Anthropiccurrent
GPT-6.1 SolOpenAIcurrent| Specification | Claude Opus 5.5 | GPT-6.1 Sol |
|---|---|---|
| Summary | Fable 5.1's level of work on most tasks, at 40% less to run than Opus 5. | Astra's score on DeepSWE, at a fifth of Astra's cost. |
| Context | 1M | 1.05M |
| Input ($/Mtok) | $4 | $2 |
| Output ($/Mtok) | $20 | $10 |
| Licence | Proprietary | Proprietary |
| Max output | 128K | 128K |
| Parameters | Not published | Not published |
| Released | 22 Sep 2026 | 29 Sep 2026 |
| Model ID | claude-opus-5-5 | gpt-6.1-sol |
| Category | Language Models | Language Models |
| Official | Anthropic ↗ | OpenAI ↗ |
Highlighted rows are where these differ.
Claude Opus 5.5
- 66.4% on Terminal-Bench 4.0 against 52.3% for Opus 5, on Anthropic's own harness
- Cache reads cut 60% to $0.20, and output more than 30% faster than Opus 5
- Attempts to work around its boundaries 85% less often than Opus 5, Anthropic reports
Best for agentic coding at flagship quality.
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.