Balanced model in OpenAI’s GPT-5.6 series, between flagship Sol and low-cost Luna. Multimodal (text, image), 1.05M-token context, for everyday coding, reasoning and agentic tasks.
Context window
1.05M
tokens
Max output
128,000
tokens
Release date
9 July 2026
Access:APIHostedDeployment:☁ Cloud
Overview
Access & deployment
APIHosted
Cloud
Weights: Closed
Key parameters
📏 Context: 1.05M
✓ Tools
📥 Input: text, image
Technical specification
Context window
1.05M
tokens
Max output tokens
128,000
tokens per response
Knowledge cutoff
16 Feb 2026
Knowledge boundary
License
Proprietary
Hardware requirements
Closed model, available only as a cloud service (OpenAI API, ChatGPT). No local hardware requirements.
Features:✓ Tool use
Modalities
⬇ Input
textimage
⬆ Output
text
Capabilities and applications
Native model capabilities
Reasoning
The model's ability to reason logically and solve complex problems.
Category: reasoning
Multi-step reasoning
Carrying out multi-step chains of reasoning across long, complex tasks.
Category: reasoning
Advanced reasoning
The ability to perform multi-step, structured reasoning: analysing problems, planning steps, and drawing conclusions from hypotheses. Reasoning-first models (e.g. GPT-5.1 Thinking) dedicate a portion of inference to chains of thought before responding.
Category: reasoning
Adaptive reasoning effort
The model decides how much 'thinking' to allocate to a given query: simple questions are answered quickly, complex problems receive more inference cycles. A GPT-5.1 feature (both Instant and Thinking) that shortens time on easy tasks and extends it for hard ones.
Category: reasoning
Coding
Generating, analysing and modifying code in many programming languages. Covers writing functions, debugging, refactoring, code review, and creating tests. Measured by benchmarks such as HumanEval and SWE-bench.
Category: coding
Agentic coding
Multi-hour, multi-step programming tasks performed autonomously by the model: cloning a repository, running tests, iterating on fixes, integrating with CLI tools. Characteristic of Codex variants (GPT-5.1-Codex-Mini, Codex-Max).
Category: coding
Agentic capability
The model's ability to autonomously plan and execute multi-step tasks by sequentially using tools, maintaining context, and adapting to intermediate results.
Category: planning
Multilingual
Competence in many natural languages (from a few to over a hundred): understanding, generation, translation, and code-switching within a single conversation. Frontier models support a wide range of languages with comparable quality.
Category: language
Computer use
The model's ability to operate a computer interface by interpreting screenshots and generating actions such as clicks, typing, and navigating applications.
Category: planning
Image understanding
Analysing and interpreting the content of images.
Category: vision
Long context
Support for large context windows — tens to hundreds of thousands (or millions) of input tokens. Enables analysis of entire codebases, long documents, and many parallel conversations without losing earlier information. GPT-5.1 supports 400,000 tokens.
Category: language
Tool use
The model's ability to call external functions, APIs and tools during a conversation: calculator, search engine, code editor, database. The model decides when and how to use a tool and interprets its result.
Category: planning
Prompt caching
Cost-performance optimisation: repeated prompt fragments (e.g. system prompt, long documentation) are cached server-side and cheaper in subsequent calls. Significantly reduces cost for applications with long contexts.
Category: other
Function Calling
Category: planning
Structured output
Producing data in structured formats such as JSON.
Category: structured_generation
Pricing
Technical architecture
Core Architecture
Model Form