GPT-5.3 Codex
by OpenAI
OpenAI’s most capable agentic coding model with 25% faster inference and interactive real-time steering
See https://openai.com/blog/gpt-53-codex
Features
- 25% faster inference than GPT-5.2-Codex
- Interactive agentic coding with real-time steering and supervision
- Multi-language software engineering (surpasses SWE-Bench Pro)
- Robust terminal and OS interaction (Terminal-Bench 2.0, OSWorld-Verified)
- Production-quality web and frontend generation
- Advanced vulnerability detection and cybersecurity analysis
- Computer use and desktop automation capabilities
- Multi-file codebase navigation and manipulation
Superpowers
GPT-5.3-Codex is the ideal tool for teams building autonomous coding agents that need real-time human oversight. Unlike previous models that work invisibly, Codex provides frequent updates on key decisions, allowing users to steer complex tasks without losing context. The 25% speed improvement makes it practical for interactive workflows where responsiveness matters.
Best for:
- Autonomous coding agents with human-in-the-loop control
- Full-stack web development (frontend and backend)
- System administration and DevOps automation
- Security research and vulnerability analysis
- Multi-file refactoring and codebase modernization
- Data analysis pipeline creation
Security-First: First OpenAI model classified as “High capability” for cybersecurity—comes with enhanced access controls and restricted API deployment through “Trusted Access for Cyber” pilot program.
Availability
- Immediate: All paid ChatGPT users via Codex app, CLI, IDE extensions, web
- Rolling: Full API access with security restrictions for high-risk cybersecurity uses
- Enable steering: Settings → General → Follow-up behavior in Codex app
Pricing
Pricing details not yet published. Full API access coming soon with security safeguards for cybersecurity use cases.