GPT-6.1 Sol: Near-Astra Performance for Complex Work at Lower Cost 2026

GPT-6.1 Sol: Near-Astra Performance for Complex Work at Lower Cost 2026 is OpenAI’s latest reasoning model, introduced in September 2026. It is designed for complex coding, computer use, professional workflows, and multi-step tasks. OpenAI says it delivers near-Astra performance while costing substantially less. Its API pricing is $2 per million input tokens and $10 per million output tokens, with cached input at $0.10. The model also supports a 1.05-million-token context window and multiple reasoning levels. These improvements make GPT-6.1 Sol particularly interesting for developers, businesses, researchers, and users who need strong reasoning without flagship-level costs.

Built for complex, long-running tasks

GPT-6.1 Sol is suited to workflows that require planning, analysis, iteration, and tool use, including:

• Complex software development and code review
• Computer-use and browser automation
• Document analysis and professional research
• Agentic workflows with multiple steps
• Large-context applications
• Repeated requests that benefit from prompt caching

The model accepts text and image inputs and produces text outputs. It supports the Responses API, Chat Completions, and Batch processing.

Model identifier

Use the following model ID:

gpt-6.1-sol

For tool calling, OpenAI recommends the Responses API. Chat Completions is supported without tool calling.

Reasoning controls

GPT-6.1 Sol supports these reasoning-effort levels:

• low
• medium — default
• high
• xhigh
• max

The none and minimal settings are not supported. Use lower reasoning effort for faster, simpler tasks and higher effort when correctness and multi-step reasoning matter more than latency.

Large context window

GPT-6.1 Sol supports:

• Context window: 1,050,000 tokens
• Maximum input: 922,000 tokens
• Maximum output: 128,000 tokens

This makes it appropriate for large repositories, extensive technical documents, long conversations, and workflows that need to preserve substantial context.

Tools and capabilities

Supported tools include:

• Web search
• File search
• Image generation
• Code Interpreter
• Hosted shell
• Computer use
• MCP
• Tool search
• Apply Patch
• Skills

The model also supports streaming, structured outputs, function calling, image inputs, and prompt caching.

Prompt caching and cost efficiency

GPT-6.1 Sol is particularly useful for applications with repeated instructions or large reusable contexts.

Cached input tokens are priced at 5% of the uncached input-token rate. Cache writes cost 1.25× the uncached input rate. For prompts exceeding 272K input tokens, higher long-context rates apply.

Batch and Flex processing are priced at 50% of Standard rates, while Fast mode costs 2× Standard pricing. Regional processing adds a 10% premium where available.

Always evaluate caching behavior with your own request patterns, because the savings depend on how much of the prompt can be reused.

Data residency

GPT-6.1 Sol supports US and EU data residency. Fast mode is unavailable with EU data residency.

Organizations with regional-processing requirements should verify endpoint, processing-tier, and feature eligibility before deployment.

GPT-6.1 Sol vs. GPT-6 Astra

Consideration	GPT-6.1 Sol	GPT-6 Astra
Positioning	Near-Astra performance at lower cost	OpenAI’s most capable model
Best for	Complex work requiring strong quality and efficiency	The hardest end-to-end tasks
Coding	Strong	Strongest
Computer use	Supported	Supported
Tool calling	Responses API	Responses API
Reasoning effort	low to max	Model-dependent
Cost strategy	Better fit for high-volume workloads	Better fit when maximum capability is the priority
Recommendation	Start here for most demanding production workloads	Use when quality is more important than cost

The practical choice should be based on evaluations using your own prompts, tools, latency requirements, and failure costs.

How can Access user GPT-6 Astra or GPT-6.1 Sol free ?

Currently, you cannot access GPT-6 Astra or GPT-6.1 Sol for free through the Free or Go plans.

• GPT-6.1 Sol: available through paid ChatGPT plans—Plus, Pro, Business, Enterprise, and Edu—in Codex or ChatGPT Work. Enterprise/Edu administrators may need to enable it.
• GPT-6 Astra: availability depends on your plan, client, workspace settings, and rollout; it is not listed as available to Free users.
• API access: requires a funded API account and usage is billed according to API pricing. There is no documented free tier for these models.

When to choose GPT-6.1 Sol

Choose GPT-6.1 Sol when you need:

1. Strong reasoning for complex coding or professional work.
2. A large context window.
3. Tool-enabled workflows through the Responses API.
4. Lower operating costs than the highest-capability model.
5. Efficient repeated processing through prompt caching.
6. Support for image inputs, structured outputs, and agentic workflows.

For simpler, high-volume requests, a smaller or faster model may be more economical. For mission-critical tasks where the last increment of quality matters most, compare Sol directly with Astra.

Example request

from openai import OpenAI

client = OpenAI()

response = client.responses.create(
    model="gpt-6.1-sol",
    reasoning={"effort": "medium"},
    input="Review this architecture and identify the highest-risk design decisions."
)

print(response.output_text)

Conclusion

GPT-6.1 Sol is positioned as a high-performance reasoning model for developers who need near-frontier capability without always paying for the most expensive model tier. Its large context window, tool support, reasoning controls, and efficient caching make it a compelling default for complex coding, agentic applications, and professional workflows.

The best deployment strategy is to benchmark GPT-6.1 Sol against GPT-6 Astra and other candidates using representative workloads, then choose based on quality, cost, latency, and reliability.

Related links

• GPT-6.1 Sol Model
• OpenAI models
• Compare models
• Model selection
• Using GPT-6 Astra
• Prompt caching
• Code generation
• Data controls in the OpenAI platform

GPT-6.1 Sol FAQs

1. What is GPT-6.1 Sol?
GPT-6.1 Sol is a reasoning model designed for complex coding, computer use, and professional workflows, offering near-Astra performance at a lower cost.

2. What is the model ID?
Use gpt-6.1-sol in API requests.

3. Which API should I use?
Use the Responses API for tool calling. Chat Completions is supported without tool calling.

4. What reasoning settings are available?
reasoning.effort supports low, medium (default), high, xhigh, and max. The none and minimal settings aren’t supported.

5. What capabilities and limits does it have?
GPT-6.1 Sol supports text and image input, streaming, structured outputs, function calling, web search, file search, and prompt caching. It has a 1,050,000-token context window and supports up to 128,000 output tokens.