The short answer
Claude Opus 5.5 vs GPT-6 Sol: specs side by side
| Claude Opus 5.5 | GPT-6 Sol | |
|---|---|---|
| Made by | Anthropic | OpenAI |
| Released | September 22, 2026 | September 22, 2026 |
| API model ID | claude-opus-5.5 | gpt-6-sol |
| Context window | 1M tokens | 1.05M tokens (922K input) |
| Max output | 128,000 tokens | 128,000 tokens |
| Knowledge cutoff | Not published | April 20, 2026 |
| Inputs | Text, images and files | Text and images |
| API price | $4 input / $20 output per 1M tokens | $2 input / $10 output per 1M tokens |
| In AimiChat | Genius quality · Aimi Genius ($100/month) | Premium quality · Aimi Ultra ($50/month) |
Which to use for each task
Large codebase changes and code review
Anthropic's published results put Opus 5.5 ahead on agentic coding, and it is built for long multi-file work.
Everyday reasoning on a budget
Sol costs half as much through the API and is designed for demanding analysis without flagship pricing.
Long reports and writing
Opus 5.5's plainer, most-important-first writing style needs fewer edits in long documents.
Math and step-by-step problem solving
Sol handles worked solutions well, and its lower cost makes it easy to run the same problem twice as a check.
What to know before you choose
Benchmarks from the two companies are not directly comparable. They use different test harnesses, effort settings and scoring (for example, Anthropic reports OSWorld 2.0 with partial credit, OpenAI reports an offline variant), so treat vendor tables as direction rather than a head-to-head score.
In AimiChat, GPT-6 Sol is available from the Aimi Ultra plan and Claude Opus 5.5 on the Aimi Genius plan, so Genius subscribers can run the same prompt through both and compare.
Published benchmarks
Each company reports different tests with different settings, so these are listed per model rather than head to head.
| Model | Benchmark | Score | Reported by |
|---|---|---|---|
| Claude Opus 5.5 | Terminal-Bench 4.0 (xhigh effort) | 66.4% | Anthropic launch post |
| Claude Opus 5.5 | GDPval-AA v2.1 (knowledge work) | 1846 | Anthropic launch post |
| Claude Opus 5.5 | Humanity's Last Exam (with tools) | 67.7% | Anthropic launch post |
| Claude Opus 5.5 | OSWorld 2.0 (partial credit) | 81.8% | Anthropic launch post |
| GPT-6 Sol | DeepSWE v1.1 (max effort) | 68.8% | OpenAI launch post, as reported by VentureBeat and Codersera |
| GPT-6 Sol | OSWorld 2.0 offline (xhigh effort) | 60.5% | OpenAI launch post, as reported by VentureBeat and Codersera |
Try both in AimiChat
Claude Opus 5.5 runs on the Genius quality and GPT-6 Sol on Premium. On a plan that includes both, you can send the same prompt twice in one chat, switching quality in between, and compare the answers directly. Read more about Claude Opus 5.5 and GPT-6 Sol, or see which plan includes which model.
Sources
Specifications and prices come from the model makers and API listings below. Benchmark figures are reported by the company that made the model and are not independent tests.