OpenAI folds Codex into main GPT-5.5 line, ends separate coding model

Romain Huet confirmed that OpenAI has discontinued the separate Codex model branch as of GPT-5.4, merging coding-specialized capabilities into the unified flagship model. GPT-5.5 continues that consolidation, with Huet citing notable improvements in agentic coding, computer use, and general on-device task execution.

The move signals OpenAI’s bet that a single general-purpose model can now match or exceed the performance of dedicated code-tuned variants — eliminating the operational overhead of maintaining parallel model lines and simplifying the developer-facing product surface. For users who relied on Codex-specific endpoints or pricing, the change forces migration onto the main GPT-5.5 API.