ModelBeat
Models/GPT-5.1-Codex
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OpenAI: GPT-5.1-Codex

openai/gpt-5.1-codex

GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows.

Context
400K
Input
$1.25 / 1M
Output
$10 / 1M
Released
Nov 12, 2025
Modalities
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Benchmarks

Scores on standardized evaluations. Higher is better — and rank shows where GPT-5.1-Codex lands among all models tracked on Model Beat.

54.0
Intelligence Index
Epoch AI
54th percentile of tracked models
44.0
Coding Index
Epoch AI
44th percentile of tracked models
64.0
Agentic Index
Epoch AI
64th percentile of tracked models

Coding

1 evals
WebDev Arena1331

Human-rated web development

Agentic & Tools

2 evals
APEX20.6%

Multi-step agentic tasks

Terminal-Bench57.8%

Command-line agentic tasks

In the news

2

Model & benchmark data from Epoch AI (CC BY); pricing, specs & descriptions from OpenRouter.