Codex, a new AI model powering its Codex coding assistant with dynamic thinking for complex, agentic software engineering tasks.

Unlike GPT-5, which is built as a general-purpose AI model, GPT-5-Codex is optimized for what OpenAI calls “agentic coding," ...

From cloud hand-offs to GitHub reviews, GPT-5-Codex is optimized for agentic coding and designed to supercharge developer workflows.

Discover GitHub Spec Kit, the open-source toolkit for spec-driven development, bringing clarity and collaboration to software projects.