GitHub Copilot Deprecates GPT-5.1-Codex Models
GitHub has deprecated the entire GPT-5.1-Codex model family across all Copilot surfaces — Chat, inline edits, ask and agent modes, and code completions — effective April 1, 2026. The affected models include GPT-5.1-Codex, GPT-5.1-Codex-Max, and GPT-5.1-Codex-Mini. This is a significant rotation for developers who built workflows around those specific models, and it underscores just how fast the AI backend landscape is moving. GitHub appears to be cycling through OpenAI's model releases more aggressively than previous generations, compressing the supported lifetime of any given model variant to a matter of months rather than years.
The deprecation comes as no surprise given OpenAI's own upstream deprecation cadence. OpenAI shipped GPT-5.1-Codex variants as bridge models between the GPT-5 family launch and the newer Codex-focused releases, but those variants are now being retired in favor of more capable successors. For Copilot users, the practical impact is that any prompt or agentic task relying on the deprecated models will need to migrate — GitHub says the changelog signals the effective date was April 1, so workspaces still using these models are now running on borrowed time.
GitHub has not yet published a detailed migration guide specifically for GPT-5.1-Codex, but the broader pattern suggests teams should align their Copilot configurations with whatever OpenAI designates as the current LTS Codex variant. The rapid deprecation cycle is a reminder that AI coding tools are still very much in the experimental phase — build accordingly, and don't assume any given model will be supported indefinitely.