GPT-5.6 Sol vs Claude Sonnet 5

Q: What are the key differences between GPT-5.6 Sol and Claude Sonnet 5?

GPT-5.6 Sol (OpenAI) and Claude Sonnet 5 (Anthropic) differ in price, context, and capability.

GPT-5.6 Sol and Claude Sonnet 5: current price, context, max output, and supported operations.

Which one to choose

Pick GPT-5.6 Sol for the hardest coding, scientific and long-agent work, where reasoning depth matters more than reply speed. Pick Claude Sonnet 5 for an everyday agent that codes, plans and browses, and that checks its own output without being asked. The deciding factor is tier: Sol is the top of the GPT-5.6 family, while Sonnet 5 is Anthropic's mid-tier model. Both read images, call tools and return structured JSON.

Pricing comparison

	GPT-5.6 Sol	Claude Sonnet 5
Model maker	OpenAI	Anthropic
Delivery availability	Available	Available
Context window	1.05M	1M
Max output	128K	128K
Official price	Input$4.00per 1M tokensOutput$20.00per 1M tokens	Input$2.00per 1M tokensOutput$10.00per 1M tokens
Verified price	Input$1.20per 1M tokensOutput$6.00per 1M tokens	Input$0.70per 1M tokensOutput$3.50per 1M tokens
Model performance	30-day success rate 98.6% 7-day median latency 21.2sn=70	30-day success rate 99.9%
Capabilities	CodeJSON modePrompt CacheReasoningTool useVision	JSON modePrompt CacheReasoningTool useVision

Choose GPT-5.6 Sol when

You hand the model scientific or technical analysis where a shallow answer is unusable.
You want to set reasoning effort per turn and spend deep thinking only where it pays.
You run long agent sessions over a repository and accept a slower, heavier model for them.

Choose Claude Sonnet 5 when

You want an agent that writes a reproducing test, fixes the bug and confirms the fix on its own.
Your work is browsing, comparing sources and compiling a sourced answer to an open question.
You prefer a mid-tier model for daily issue-to-fix coding work rather than a flagship.

How they differ

Aspect	GPT-5.6 Sol	Claude Sonnet 5
Model tier	The flagship of the GPT-5.6 family, above Terra and Luna, aimed at the most demanding work.	Anthropic's mid-tier model, built as the everyday agent model rather than the top Claude tier.
Working style	Built for long agent sessions where deep, sustained reasoning is the point.	Anthropic describes it as checking its own work and finishing tasks where earlier models stopped short.
Sampling controls	Behaviour is steered through the reasoning setting, not through sampling values.	Non-default temperature, top_p or top_k values are rejected, so remove those settings from existing code.
Research and browsing	Strongest in scientific analysis and complex professional documents.	Anthropic highlights agentic web search, where it is reported to match its larger Opus sibling at medium effort.
Lifecycle	OpenAI lists the GPT-5.6 family as legacy and points new projects to GPT-6.	Anthropic's newer Sonnet 5.5 is the current Sonnet, so this one suits integrations already built on it.

Summary

GPT-5.6 Sol: Input $1.20 / Output $6.00 per 1M tokens; Claude Sonnet 5: Input $0.70 / Output $3.50 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.

GPT-5.6 Sol

GPT-5

View details

Claude Sonnet 5

Claude 5

View details

FAQ

Is GPT-5.6 Sol better than Claude Sonnet 5?

They sit in different tiers. GPT-5.6 Sol is OpenAI's flagship for deep, complex work, and Claude Sonnet 5 is Anthropic's mid-tier everyday agent model. Pick Sol when depth decides the result, and Sonnet 5 when you want a steady coding and browsing agent.

Which is better for coding agents?

Both target agentic coding. Sol suits long multi-file sessions that need heavy reasoning; Sonnet 5 suits day-to-day issue fixing where the model writes a test and checks its own change. Run both on your own repository tasks to see which finishes more cleanly.

Can I swap one for the other without changing prompts?

Not safely. Sonnet 5 rejects non-default temperature, top_p and top_k, while Sol is steered through reasoning effort. Prompts tuned for one usually need a pass on tool descriptions and output format before the other behaves the same way.

Are these the newest models of their makers?

No. OpenAI now recommends GPT-6 models for new builds, and Anthropic's Sonnet 5.5 has replaced Sonnet 5 as the current Sonnet. Choose these two when you already depend on them or have measured them on your own tasks.

Which is cheaper, GPT-5.6 Sol or Claude Sonnet 5?

GPT-5.6 Sol: Input $1.20 / Output $6.00 per 1M tokens; Claude Sonnet 5: Input $0.70 / Output $3.50 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-5.6 Sol and Claude Sonnet 5?

GPT-5.6 Sol: Code

Sources

Reviewed Oct 2, 2026