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OpenAI Advanced

GPT-5.6 Sol

GPT-5.6 Sol is OpenAI's flagship GPT-5.6 model with 1.05M context, 128K output, advanced tools and current $4/M input pricing.

General Purpose Language ModelTextImage Paid
In plain English

What is this model and why does it matter?

GPT-5.6 Sol is OpenAI's flagship GPT-5.6 model for complex professional reasoning, coding and tool-using workflows.

Complex reasoningCodingProfessional workAgentsLarge documentsComputer use
Model overview

GPT-5.6 Sol: features, use cases and important details

GPT-5.6 Sol is the flagship model in OpenAI’s GPT-5.6 family.

Verified model facts

Official documentation lists a 1.05M-token context window, 128K maximum output, February 16 2026 knowledge cutoff, text/image input, reasoning controls and broad Responses API tools.

Current status

It is active on the OpenAI API and the gpt-5.6 alias routes to Sol.

Best fit

It fits complex professional tasks, coding agents, research and large-document workflows where frontier performance matters.

Limitations

It costs more than Terra or Luna, very long prompts use higher rates, and external tools are still needed for current information.

Get started

How to use this model

  1. Create an OpenAI API key.
  2. Call gpt-5.6-sol or the gpt-5.6 alias.
  3. Set reasoning effort for the task.
  4. Enable Responses API tools when needed.
  5. Monitor long-context pricing above 272K input tokens.
Copy and try

Example prompts

  • Analyze this complex business problem and recommend a decision.
  • Implement and test this multi-file coding change.
  • Research this topic with tools and return a structured report.
Capabilities

What it can do

  • 1.05M context
  • 128K output
  • Reasoning
  • Coding
  • Computer use
  • Web search
  • Structured outputs
  • Function calling
Best for

Practical use cases

  • Professional work
  • Coding agents
  • Research
  • Enterprise automation
  • Long-context analysis
Pricing

What does it cost?

$4.00 per 1M input tokens, $0.40 per 1M cached input and $20.00 per 1M output. Promotional pricing is listed through at least November 21, 2026.

Input$4.00 / 1M tokens
Output$20.00 / 1M tokens
Simple summaryCurrent standard pricing is $4/M input and $20/M output, with higher rates for prompts above 272K input tokens.

What stands out

  • Strong flagship capability
  • Huge context
  • Broad tool support
  • Lower price than GPT-6 Astra

Things to consider

  • More expensive than Terra/Luna
  • Proprietary
  • Long-context surcharge
Limitations

Important restrictions and trade-offs

  • February 2026 knowledge cutoff without tools
  • Long prompts cost more
  • Can still hallucinate or misuse tools
SimplifyAITools verdict

Our editorial take

A strong default OpenAI model when GPT-6 Astra is unnecessary or too expensive.

References

Primary sources

  1. Open source 1 ↗
  2. Open source 2 ↗
  3. Open source 3 ↗
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