GPT-6.1 Sol API

Technical Specifications of GPT-6.1 Sol

OpenAI lists GPT-6.1 Sol with a 1.05-million-token context window, 128K maximum output, and a knowledge cutoff of April 30, 2026. The model accepts text and image input and produces text output.

What Is GPT-6.1 Sol?

GPT-6.1 Sol is an OpenAI model in the GPT-6.1 family designed for complex coding, computer use, and professional work. OpenAI describes it as providing near-GPT-6 Astra performance at a lower token cost, while emphasizing a balance between capability, speed, and affordability.

The model combines a 1.05-million-token context window with configurable reasoning effort and extensive Responses API tool support. This makes it suitable for applications that need to process large amounts of context, perform multi-step reasoning, interact with external tools, or work across software and computer-use environments.

GPT-6.1 Sol supports five reasoning levels: low, medium, high, xhigh, and max. medium is the default, while none and minimal are not supported.

Main Features of GPT-6.1 Sol

1. 1.05M-Token Context Window

GPT-6.1 Sol provides a 1,050,000-token context window with up to 128,000 output tokens. The large context capacity is useful for large repositories, lengthy technical documentation, extensive research material, and long-running agent sessions.

2. Configurable Reasoning Effort

Developers can control the amount of reasoning used by setting reasoning.effort to low, medium, high, xhigh, or max.

This gives applications a way to trade reasoning depth against latency and token consumption. The default setting is medium. Unlike some earlier GPT models, GPT-6.1 Sol does not support none or minimal reasoning effort.

3. Advanced Coding and Agentic Workflows

OpenAI specifically positions GPT-6.1 Sol for complex coding and professional work. Its combination of long context, reasoning, function calling, and Responses API tools makes it suitable for repository-level development, debugging, code modification, and multi-step engineering agents.

4. Broad Responses API Tool Support

GPT-6.1 Sol supports a broad set of tools through the Responses API, including:

• Web search
• File search
• Code interpreter
• Computer use
• Hosted shell
• Apply patch
• MCP
• Tool search
• Skills
• Image generation

This allows GPT-6.1 Sol to operate as part of an agentic application rather than being limited to standalone text generation.

5. Multimodal Input

GPT-6.1 Sol accepts both text and image input. This enables applications to combine textual instructions with screenshots, diagrams, charts, UI images, and other visual information.

Audio and video are not supported as native input modalities for this model.

6. Flexible API Integration

GPT-6.1 Sol is available through both the Responses API and Chat Completions. However, OpenAI specifies that tool calling requires the Responses API. Chat Completions can be used for requests without tools.

Benchmark Performance of GPT-6.1 Sol

OpenAI's September 29, 2026 system-card addendum reports GPT-6.1 Sol across a range of capability and safety evaluations. For example, on the production safety benchmark described in the system card, GPT-6.1 Sol scored higher than GPT-6 Sol in five of eight evaluated categories.

OpenAI also reports the following cybersecurity-related evaluation results:

These are specialized evaluations rather than general-purpose intelligence benchmarks. The results should therefore be interpreted within the methodology and scope of each evaluation rather than treated as a universal measure of model performance.

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Limitations and API Considerations

GPT-6.1 Sol has several implementation details developers should account for:

• No none or minimal reasoning: low is the lowest available reasoning effort.
• Tool calling requires Responses API: Chat Completions does not provide tool calling for GPT-6.1 Sol.
• No fine-tuning: Fine-tuning is currently unavailable for this model.
• No native audio or video input: The model accepts text and images but not audio or video.
• EU Fast mode limitation: Fast mode is unavailable when EU data residency is configured.
• Large-context pricing: Requests above 272K input tokens have different input, cache, and output pricing.

These limitations are particularly relevant when migrating an existing GPT integration. OpenAI recommends reviewing reasoning settings and tool-calling behavior when moving to GPT-6.1 Sol.

GPT-6.1 Sol Use Cases

Agentic Software Engineering

GPT-6.1 Sol is designed for complex coding workflows involving repository analysis, debugging, code generation, refactoring, and multi-step development tasks. Its long context helps agents retain more repository and task information during extended sessions.

Computer-Use Agents

With computer-use support through the Responses API, GPT-6.1 Sol can participate in workflows involving interactive software environments and visual interfaces. This makes it relevant to browser automation, desktop workflows, testing, and other computer-use applications.

Large-Scale Document Analysis

The 1.05M-token context window makes GPT-6.1 Sol suitable for processing large technical documents, extensive research collections, specifications, and other long-context workloads.

Professional Knowledge Work

OpenAI explicitly identifies professional work as a target use case. Applications can combine GPT-6.1 Sol's reasoning capabilities with file search, web search, code execution, and other tools to build multi-step research and productivity workflows.

Tool-Using AI Agents

GPT-6.1 Sol supports a broad set of Responses API tools, making it suitable for agents that need to search the web, retrieve files, execute code, interact with computers, call MCP servers, or modify code through tools.

How to Access GPT-6.1 Sol API

You can access GPT-6.1 Sol through CometAPI without building a separate provider integration. The basic process is straightforward: create a CometAPI API key, specify the gpt-6.1-sol model ID, and send your request through CometAPI's OpenAI-compatible API.

Step 1: Create a CometAPI API Key

First, create or sign in to your CometAPI account and generate an API key from the API Keys section.

Keep the key secure and store it as an environment variable rather than hard-coding it directly into your application.

For example:

export COMETAPI_KEY="your_cometapi_api_key"

Step 2: Select GPT-6.1 Sol

Use the following model ID in your API request:

gpt-6.1-sol

CometAPI provides an OpenAI-compatible interface, so developers familiar with the OpenAI SDK can generally reuse the same SDK structure while changing the API key, base URL, and model ID. CometAPI currently documents the /v1/responses endpoint for its OpenAI-compatible model integrations.

The CometAPI API base URL is:

https://api.cometapi.com/v1

Step 3: Send Your First GPT-6.1 Sol Request

The simplest way to test GPT-6.1 Sol is with the Responses API

The three parameters that matter are:

• API endpoint: https://api.cometapi.com/v1/responses
• Model: gpt-6.1-sol
• Authentication: your CometAPI API key

Why Use CometAPI for GPT-6.1 Sol?

CometAPI provides a unified API layer for accessing supported AI models. Instead of creating a separate integration for every model provider, developers can use the same API workflow and switch the model identifier when moving between supported models.

For applications that already use OpenAI-compatible SDKs, this can simplify model testing, migration, and multi-model development.

In short: create your CometAPI key, set the CometAPI base URL, specify gpt-6.1-sol, and send the request through the Responses API.