GPT-5-Codex
GPT-5-Codex is the GPT-5 specialization for agentic software engineering in Codex. It was trained for implementation, debugging, substantial refactors, and code review, adjusting its reasoning to task complexity. It supports interactive collaboration and sustained tool-based work. The API exposed it through Responses, while Codex provided terminal, IDE, cloud, and review workflows.
2025-09-15
Unreleased
Undisclosed proprietary architecture
Proprietary
Specifications
- Parameters
- Unreleased
- Architecture
- Undisclosed proprietary architecture
- License
- Proprietary
- Context Window
- 400,000 tokens
- Max Output
- 128,000 tokens
- Training Data Cutoff
- Sep 30, 2024
- Type
- multimodal
- Modalities
- textimage
Benchmark Scores
Advanced Specifications
- Model Family
- GPT-5
- API Access
- Not Available
- Chat Interface
- Not Available
- Variants
- gpt-5-codex
Capabilities & Limitations
- Capabilities
- agentic codingcode reviewdebuggingvisiontool use
- Known Limitations
- Can produce incorrect factual claims or code; important results require independent verification.This API identity was retired on July 23, 2026; preserved for historical coverage.
- Notable Use Cases
- repository maintenancecode reviewproject refactoring
- Function Calling Support
- Yes
- Tool Use Support
- Yes