LLM Reference

GPT-5.1 Codex

Proprietary

About

Codex variant of GPT-5.1 from OpenAI, optimized for code generation tasks. Earlier generation of the Codex coding agent model line preceding GPT-5.3 Codex.

Capabilities

MultimodalFunction CallingTool UseJSON Mode

Specifications

FamilyCodex
Released2025-12-01
ArchitectureDecoder Only
Knowledge cutoff2025-08
Specializationcode-generation
LicenseProprietary
Trainingpretraining