OpenAI: GPT-5.1-Codex
Analysis Summary
GPT-5.1-Codex is OpenAI's coding-specialised variant in the GPT-5.1 family, supporting image and text inputs with tool use and function calling across a 400K context window. Its livecodebench score of 0.849 and terminalbench hard score of 0.348 are strong, and its agentic index of 58.9 places it among the more reliable models for multi-step autonomous tasks.
For businesses, it is best suited to software engineering automation, code review, agentic coding pipelines, and long-context code analysis. Instruction following at 0.70 and long-context reliability at 0.673 are both good. Its intelligence index of 34.7 is slightly below GPT-5.1, so for tasks requiring broad reasoning beyond code, the full GPT-5.1 is the stronger choice.
At $1.25 input and $10.00 output per million tokens, it shares GPT-5.1's pricing. Teams with a primary focus on coding and agentic software tasks will find it well-matched to those workloads, with the OpenAI ecosystem's tooling and reliability as an additional practical advantage.
Assessed June 17, 2026
Editorial notes
GPT-5.1-Codex from OpenAI pairs strong coding and agentic benchmarks with vision support and a 400K context window, offering reliable performance for software engineering and autonomous pipeline tasks.
Rankings consider pricing, capabilities, benchmarks, and real-world applicability and are refreshed as new models launch. Feedback?
Performance Profile
How OpenAI: GPT-5.1-Codex compares
OpenAI: GPT-5.1-Codex ranks #54 of 382 AI models we track for overall intelligence, #67 of 293 for agentic tasks. Its 400K-token context window is larger than 85% of the models we list. At $1.25 per million input tokens it is cheaper than 21% of comparable models.
About OpenAI: GPT-5.1-Codex
GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows. It is designed for both interactive development sessions and long, independent execution of complex engineering tasks..
Capabilities
Performance Indices
Source: Artificial Analysis
Benchmark Scores
Intelligence
Technical
Content
Benchmark data from Artificial Analysis and Hugging Face
How does OpenAI: GPT-5.1-Codex stack up?
Compare side-by-side with other specialist models.
Model Information
| OpenRouter ID |
openai/gpt-5.1-codex
|
| Provider | openai |
| Release Date | November 13, 2025 |
| Context Length | 400,000 tokens |
| Max Completion | 128,000 tokens |
| Status | Active |
Pricing
| Token Type | Cost per 1M tokens | Cost per 1K tokens |
|---|---|---|
| Input | $1.25 | $0.001250 |
| Output | $10.00 | $0.010000 |
Live Performance
Live endpoint metrics, refreshed every 30 minutes.
Leaderboard Categories
External Resources
Frequently asked questions about OpenAI: GPT-5.1-Codex
How much does OpenAI: GPT-5.1-Codex cost?
OpenAI: GPT-5.1-Codex costs $1.25 per million input tokens and $10.00 per million output tokens.
What is the context window of OpenAI: GPT-5.1-Codex?
OpenAI: GPT-5.1-Codex has a context window of 400,000 tokens (400K).
What can OpenAI: GPT-5.1-Codex do?
OpenAI: GPT-5.1-Codex supports image/vision input, tool use, and function calling.
Who created OpenAI: GPT-5.1-Codex?
OpenAI: GPT-5.1-Codex is developed by OpenAI and was released on November 13, 2025.
