Model · OpenAI · Code
GPT-5.3-Codex
OpenAI's agentic coding model of the GPT-5.3 generation — tuned for long-horizon software engineering, tool use, and the Codex agent surface. Deprecated 2026-10-01 with shutdown 2027-04-01.
- Modality
- Code
- License
- Proprietary (Proprietary)
- Context window
- 400,000 tokens
- Released
- February 5, 2026
- Last verified
- October 28, 2026
- Runs locally
- No
- Also handles
- text
Strengths
- Tuned for agentic, multi-step coding in the Codex agent surface
- 400k-token context (128k max output)
- Powers the Codex agent in ChatGPT and the API
Weaknesses
- Specialised for coding/agentic work rather than general chat
- Closed weights — API/product only
Try it
| Where | Type | Notes |
|---|---|---|
| OpenAI API | hosted-api | API key required |
| ChatGPT / Codex | product | Codex agent surface |
Version history
- GPT-5.6 Luna Jul 2026 Deprecated
- GPT-5.6 Sol Jul 2026 Deprecated
- GPT-5.6 Terra Jul 2026 Deprecated
- GPT-5.5 Apr 2026 Deprecated
- GPT-5.4 mini Mar 2026 Deprecated
Official sources
- Model docs docs
- Announcement announcement
Change log
- — Deprecated — superseded by GPT-6.1 Sol. OpenAI announced deprecation 2026-10-01 (lab replacement gpt-6-sol); lab shutdown 2027-04-01.
- — Initial entry (2026-06-08 catalog refresh, Tier 3). Released 2026-02-05; OpenAI's flagship agentic coding model.
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