GPT-6 Sol vs Claude Opus 5.5
Which one to choose
Pick GPT-6 Sol if you already run GPT-6 in production and want a reasoning setting of none for quick calls. Pick Claude Opus 5.5 for long-running agentic coding, desktop and browser automation, and multi-hour knowledge work. The deciding factor is task length and tier: Opus 5.5 is Anthropic's current top Opus built to stay on task for hours, while Sol is OpenAI's mid-to-upper GPT-6 model, now succeeded by GPT-6.1 Sol.
Pricing comparison
| GPT-6 Sol | Claude Opus 5.5 | |
|---|---|---|
| Model maker | OpenAI | Anthropic |
| Delivery availability | Available | Available |
| Context window | 1.05M | 1M |
| Max output | 128K | 128K |
| Official price | Input$2.00per 1M tokensOutput$10.00per 1M tokens | Input$4.00per 1M tokensOutput$20.00per 1M tokens |
| TokenLab price | Input$0.60per 1M tokensOutput$3.00per 1M tokens | Input$1.20per 1M tokensOutput$6.00per 1M tokens |
| Model performance |
|
|
| Capabilities | CodeJSON modePrompt CacheReasoningTool useVision | JSON modePrompt CacheReasoningTool useVision |
Choose GPT-6 Sol when
- You need a model that can answer with reasoning switched off for simple turns.
- Your existing integration is GPT-6 Sol and you want to compare it with a Claude model on your own evaluations.
- You want images and schema-checked JSON next to tool calls in one request.
Choose Claude Opus 5.5 when
- You assign multi-hour jobs such as a large migration or an architecture audit and check back later.
- You automate desktop or browser software from screenshots where no API exists.
- Your agents hold state over very long runs and must not drift from the plan.
How they differ
| Aspect | GPT-6 Sol | Claude Opus 5.5 |
|---|---|---|
| Thinking behaviour | Reasoning can be set to none or raised for harder turns. | Adaptive thinking is always on and cannot be disabled. |
| Tool use | Calls tools alongside schema-checked JSON output. | Forced tool use returns an error, which breaks code written for Opus 5. |
| Run length | Built for complex coding and agentic workflows at a step below OpenAI's top GPT-6 model. | Anthropic stresses long autonomous runs, with a customer agent working more than 18 hours. |
| Computer use | OpenAI cites gains in computer use over GPT-5.6 Sol. | Anthropic reports OSWorld 2.1 results and presents desktop and browser automation as a core use. |
| Streaming progress | Standard output streaming. | Text between tool calls arrives in thinking blocks that are empty by default, so progress text needs a display setting. |
| Lifecycle | OpenAI recommends GPT-6.1 Sol for new projects. | Anthropic's current Opus, released in September 2026. |
Summary
- GPT-6 Sol: Input $0.60 / Output $3.00 per 1M tokens; Claude Opus 5.5: Input $1.20 / Output $6.00 per 1M tokens. Rates depend on the billing unit, specification, and usage. Compare matching conditions in the model's detailed pricing; a single rate does not determine the total cost.
FAQ
Which is better for long autonomous coding sessions?
Claude Opus 5.5 is the one Anthropic builds for hours-long agentic coding and knowledge work. GPT-6 Sol handles agentic coding too, but OpenAI now points new work to GPT-6.1 Sol, so compare Opus 5.5 with that model if you are starting fresh.
Can I turn thinking off on either model?
On GPT-6 Sol, yes: its reasoning setting accepts none. On Claude Opus 5.5, adaptive thinking is always on, so latency-sensitive simple calls are better served by a faster model.
Will my GPT-6 Sol tool code work with Opus 5.5?
Check it first. Opus 5.5 returns an error when tool use is forced, and tool definitions differ between the two families, so test your agent loop before switching.
Which is the newer model?
Opus 5.5 is newer than GPT-6 Sol by a few days, but they come from different makers and are not predecessor and successor. OpenAI's own newer option is GPT-6.1 Sol.
Which is cheaper, GPT-6 Sol or Claude Opus 5.5?
GPT-6 Sol: Input $0.60 / Output $3.00 per 1M tokens; Claude Opus 5.5: Input $1.20 / Output $6.00 per 1M tokens. Rates depend on the billing unit, specification, and usage. Compare matching conditions in the model's detailed pricing; a single rate does not determine the total cost.
What are the key differences between GPT-6 Sol and Claude Opus 5.5?
GPT-6 Sol: Code
Sources
- Introducing GPT-6 Sol and Luna
- Using GPT-6 (model guidance)
- Introducing Claude Opus 5.5
- Claude Opus 5.5 model overview
Reviewed Oct 2, 2026