gpt-5-codex

Basic Information

GPT‑5-Codex is an optimized version of GPT‑5 released by OpenAI on September 15, 2025, specifically designed for intelligent coding tasks on the Codex platform. It will be available to API key developers and ChatGPT subscribers starting September 23, accessible only through the Responses API. Its pricing is consistent with GPT‑5, and the base model snapshots are updated regularly. It is compatible with all Codex scenarios, including CLI, IDE extensions, cloud environments, and GitHub integration, and is offered as part of paid plans such as ChatGPT Plus and Pro. GPT‑5-Codex focuses on real-world software engineering needs and can handle tasks ranging from quick interactions to complex standalone projects.

Core Features

It excels at end-to-end coding tasks, enabling users to build projects from scratch, add features and run tests, perform large-scale refactoring (such as modifying 3,541 lines of code across 232 files), and conduct code reviews. It supports multimodal collaboration, allowing it to read screenshots, wireframes, and other visual inputs to generate code that aligns with design specifications, and even produce feedback in the form of working screenshots. Following the AGENTS.md guidelines, it can generate high-quality code without lengthy style instructions, and significantly boosts human preference in front-end development (for mobile websites and desktop applications).

Technical Highlights

It features dynamic reasoning capabilities, adjusting its thinking time based on task complexity: simple tasks are responded to quickly, while complex tasks can work independently for over 7 hours. SWE-bench validation covers all 500 tasks, and its code review function ensures code correctness, reducing unnecessary comments. Efficiency has been markedly optimized—token consumption in low-token scenarios is 93.7% lower than GPT‑5, while in high-complexity tasks, reasoning time doubles to maintain quality.

Market Impact

It eases the burden on development teams by automating PR reviews and handling refactoring, thus accelerating delivery. It drives innovation in coding collaboration models, enabling seamless integration between local and cloud environments and boosting development efficiency. Its secure sandbox environment and customizable permissions meet enterprise data protection requirements, setting a new benchmark for performance and security in intelligent coding tools.