OpenAI Merges Codex Into Main Model Starting with GPT-5.4, Discontinues Separate Coding Line

Gate News message, April 26 — OpenAI's head of developer experience Romain Huet revealed in a recent statement on X that Codex, the company's independently maintained specialized coding model line, has been merged into the main model starting with GPT-5.4 and will no longer receive separate updates.

GPT-5.5 builds on this consolidation with notable enhancements in agentic coding (agent-driven autonomous programming) and computer use (executing computer tasks autonomously). The integration means developers no longer need to choose between general-purpose and specialized coding models—a single model now handles conversational, reasoning, and coding capabilities simultaneously.