Model · Multimodal language model
GPT-5.3 Codex
The February 2026 agentic-coding release for Codex, served Responses-only as the gpt-5.3-codex alias with no fixed dated snapshot and no API retirement entry, without downloadable model weights.
- Developer
- OpenAI
- Distribution
- Developer API
- Artifact licensing
- Proprietary access
- License scope
- Reviewed release artifacts and mandatory terms; not an assessment of training code or training data openness.
- Licenses
- OpenAI Services Agreement
- Boundary
- This record represents the GPT-5.3-Codex line launched February 5, 2026 and served as the gpt-5.3-codex alias with no fixed dated revision, so applications cannot pin a dated snapshot; the API deprecation page carries no retirement entry for this line as of review. The Spark research preview, Codex application behaviors, earlier Codex generations, fine-tuned derivatives, and the OpenAI API platform itself are separate service, application, or model boundaries.
Risk statements
“High” · Precautionary
As discussed in more detail below, this is the first launch we are treating as High capability in Cybersecurity. Thus, we consider the safeguards associated with High cybersecurity capability to be a necessary precaution. We are also treating GPT-5.3-Codex as High risk in the Biological and Chemical domain, and applying the same safeguards as for our other deployments of models that reach this designation.
- Risk areas
- Cyber · Biological or chemical
- Covers
- The model itself
Read the developer's statement ↗ · 2026-10-09 · Research confidence: High
OpenAI names this release against “High” in cyber and biological or chemical capability, as a precaution. The statement covers the model itself. This is the developer's own statement, not an Atlas risk rating.
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