- Provider
- OpenAI
- Family
- GPT-5
- Context window
- 400,000 tokens
- Modality
- text, vision, tool use
- Knowledge cutoff
- August 2025
- Last updated
- 2026-05-19
At a glance
GPT-5.3-Codex is OpenAI's current code-specialised model for Codex and similar agentic coding environments. It is tuned for multi-file edits, long-running development tasks, and codebase-aware tool use.
Strengths
- Strong at multi-file edits and codebase-aware tasks
- Native fit for Codex CLI workflows
- Good tool-use for shell, editor, and test-runner integrations
Weaknesses
- Narrower than general GPT-5.5 for non-code reasoning
- Best used inside the Codex CLI or an equivalent harness
Best for
- Codex CLI sessions
- Automated code edits over a working directory
- Pair-programming style dev agents
GPT-5.3-Codex vs Claude Code
Claude Code and Codex CLI are the two leading terminal-first AI coding agents. Claude Code pairs particularly well with Sonnet 4.6 and Opus 4.7; Codex runs on the GPT Codex family. Most serious developers end up running both. Vibecode is specifically built to show combined spend and session patterns across the two.
Tracking Codex usage
Vibecode ingests Codex CLI usage artifacts alongside Claude Code, so GPT-5.3-Codex token spend shows up on the same daily chart and in the yearly wrapped recap as Claude. That is the fastest way to see whether your dev work is GPT- or Claude-dominated and how cost is trending.
Frequently asked questions
What is GPT-5.3-Codex?
GPT-5.3-Codex is OpenAI's current code-specialised model for Codex and similar agentic coding tools. It is tuned for multi-file edits and codebase-aware tasks.
How do I see GPT-5.3-Codex usage?
Use Vibecode at wolfai.dev/vibecode. It ingests Codex CLI artifacts and shows per-model spend for GPT-5.3-Codex alongside Claude Code usage in one dashboard.