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GPT-5.1-Codex and GPT-5.1-Codex-Mini Now Available

GPT-5.1-Codex and GPT-5.1-Codex-Mini are now available in Codex. These models are optimized for agentic coding tasks. macOS/Linux default to the full model; Windows stays on GPT-5.1.

GPT-5.1-Codex and GPT-5.1-Codex-Mini Now Available

TL;DR

  • GPT-5.1-Codex and GPT-5.1-Codex-Mini now available in Codex CLI and IDE Extension
  • macOS/Linux default to gpt-5.1-codex; Windows defaults to gpt-5.1
  • Models optimized for long-running agentic coding tasks

New

  • gpt-5.1-codex — Full-size model optimized for agentic coding workflows and long-running tasks in Codex harnesses
  • gpt-5.1-codex-mini — Lightweight variant for resource-constrained environments

Changed

  • Default model behavior — macOS and Linux now default to gpt-5.1-codex; Windows remains on gpt-5.1

How to Switch

  • One-off session: codex --model gpt-5.1-codex or use /model slash command in CLI
  • IDE Extension: Select GPT-5.1-Codex from the dropdown menu
  • Persistent: Update config.toml with model = "gpt-5.1-codex"

Update Codex to the latest version to access these models: pip install --upgrade codex

Source: Codex

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