GPT 5 Codex

GPT-5-Codex extends the GPT-5 foundation with domain-focused training for software engineering. It maps natural language prompts to production-ready code across a wide range of languages, including Python, JavaScript/TypeScript, Java, C/C++, Go, and Rust, while also supporting frameworks, APIs, and shell scripting. With long-context capabilities, it can track entire repositories or multi-file projects, enabling coherent reasoning across modules and dependencies.

The model is designed for multiple coding workflows: inline completion and fill-in-the-middle within IDEs, step-by-step explanations of algorithms, automated bug fixing, and structured test generation. It can output schema-consistent formats such as diffs or JSON patches, making it simple to wire into CI/CD pipelines, code review agents, or automated refactoring tools.

GPT-5-Codex also supports function calling, so it can trigger external tools (linters, compilers, documentation generators) within agent frameworks. Streaming output ensures responsiveness in interactive settings, while quantization and inference optimizations allow deployment at scale. Teams typically use GPT-5-Codex for repo-aware copilots, automated pull-request generation, educational coding assistants, and enterprise software modernization projects.