Summary

GPT-5.3-Codex from OpenAI is now generally available in GitHub Copilot (announced Feb 9, 2026), but it's not yet listed in models.dev under the github-copilot provider.

"GPT-5.3-Codex, OpenAI’s latest agentic coding model, is now rolling out in GitHub Copilot. In early testing, GPT-5.3-Codex reaches new high scores on benchmarks we use to evaluate coding, agentic, and real-world capabilities. It also has improved reasoning and execution in complex, tool-driven, long-running workflows which help it to deliver up to 25% faster performance than GPT-5.2-Codex on agentic coding tasks."

GitHub blog announcement: https://github.blog/changelog/2026-02-09-gpt-5-3-codex-is-now-generally-available-for-github-copilot/

GitHub Docs (supported models): https://docs.github.com/copilot/reference/ai-models/supported-models