OpenAI on Monday released GPT‑5‑Codex, a version of GPT‑5 optimized for agentic software engineering in Codex. The company said the model excels at both quick, interactive coding sessions and independently handling long, complex tasks. Its code review capabilities can detect critical bugs before deployment.
Since the initial launches of Codex CLI in April and Codex Web in May, Codex has evolved into a more effective coding collaborator. Two weeks ago, OpenAI unified Codex into a single product experience connected to your ChatGPT account, enabling seamless workflow between local and cloud environments.
OpenAI stated these updates bring Codex closer to its goal of being a teammate that understands context, collaborates with developers, and reliably executes tasks.
GPT‑5‑Codex: Features and Capabilities
GPT‑5‑Codex is trained on complex, real-world software engineering tasks, including:
- Building full projects from scratch
- Adding features and tests
- Debugging and performing large-scale refactors
- Conducting code reviews
It is highly steerable, follows AGENTS.md instructions accurately, and produces high-quality code without lengthy instructions on style or cleanliness.
Key capabilities:
- Adaptive reasoning: GPT‑5‑Codex adjusts thinking time based on task complexity, working independently for over 7 hours on large projects.
- Token efficiency: For simpler tasks, it uses 93.7% fewer tokens than GPT‑5; for complex tasks, it spends twice as long iterating and testing.
- Code review: Navigates dependencies, executes tests, and identifies critical flaws with fewer irrelevant comments.
- Front-end tasks: Creates desktop apps and mobile websites with improved human-preference evaluations, and can inspect and output screenshots for visual feedback.
GPT‑5‑Codex is designed specifically for Codex CLI, IDE extensions, Codex cloud, and GitHub, and is recommended only for agentic coding tasks.
Updates to Codex
Codex CLI
The open-source Codex CLI has been rebuilt for agentic workflows:
- Shared context: Attach and share screenshots, wireframes, and diagrams
- Progress tracking: Includes to-do lists and access to web search and MCP tools
- Enhanced terminal UI: Better-formatted tool calls and diffs; simplified approval modes (read-only, auto, full access)
- Session management: Compact conversation state for longer workflows
Codex IDE Extension
The IDE extension integrates Codex into VS Code, Cursor, and other VS Code forks:
- Preview and edit local changes seamlessly
- Shorter prompts for faster results using context from opened files
- Move work between cloud and local environments without losing context
Codex Cloud
Codex cloud integrates CLI, IDE, and GitHub:
- Delegate tasks without switching applications
- Faster completion: Median task time reduced by 90% through container caching
- Automatically sets up environments, fetches dependencies, and visually inspects front-end work
Code Review Capabilities
Codex now provides advanced code review:
- Matches PR intent to actual diffs, reasons across the codebase, and executes tests
- Automatically reviews GitHub PRs, catching hundreds of issues daily
- Developers can request focused reviews, such as for security or outdated dependencies
- Serves as a supplementary reviewer, not a replacement for humans
Safety and Trustworthiness
Codex prioritizes safety:
- Runs in a sandbox with network access disabled by default
- Requests permission for potentially dangerous actions
- Provides citations, terminal logs, and test results for transparency
- Developers can customize network and command access
GPT‑5‑Codex is treated as high capability in biological and chemical domains, with safeguards to minimize risks.
Pricing and Availability
Available with ChatGPT Plus, Pro, Business, Education, and Enterprise subscriptions.
- Usage scales with plan; Pro supports full-week coding across multiple projects
- Business plans can purchase additional credits; Enterprise plans offer a shared credit pool
- GPT‑5‑Codex is default for cloud tasks and code review, available locally via CLI and IDE
- Works in terminal, IDE, web, GitHub, and ChatGPT iOS app
- API availability for GPT‑5‑Codex is coming soon
Speaking about the update, the company said:
Codex is becoming the coding partner we’ve always envisioned—one that’s faster, more reliable, and deeply integrated into the tools you already use. We’re excited to see what you create with it and will keep improving Codex to make it an even better teammate for your most ambitious projects.