Codex is a development assistant launched by OpenAI that automatically generates, modifies, and reviews code in local terminals, IDEs, and the cloud. It can not only call its own dedicated Codex series models, but also run in combination with GPT-5 and o series models to meet the programming needs of different scenarios.
model type that can work with Codex
- : This is the recommended and default model for Codex CLI and IDE extensions, supporting multi-level reasoning levels, suitable for general code generation and Q&A.
- codex-1 and codex-mini-latest: codex-1 is used for cloud agents, supporting complex task decomposition and team collaboration; codex-mini-latest is CLI-oriented, optimized based on o4-mini, low latency, and suitable for rapid iteration of personal development.
- O-Series Models (o3, o4-mini): Codex CLI is compatible with these models to continue existing workflows and facilitate a smooth transition from legacy systems.
- Legacy Model Access: Users can specify legacy models through API Keys, but officials recommend prioritizing GPT-5 and codex models for the best experience.
2. Model selection team development in different scenarios
- : It is recommended to combine Codex Cloud with codex-1 to support code review, automatic PR generation, and test tracking, making it suitable for multi-person collaboration and large-scale projects.
- Personal development: Recommend Codex CLI + GPT-5 to quickly complete refactoring, debugging, and Q&A; If low latency is a concern, choose codex-mini-latest.
- Migration scenario: If you already have an O-series model workflow, you can continue to use O3 or O4-mini, and switch to Codex-1 when more complex tasks are required.
Frequently Asked Questions (Q&A)
Q: Which model does Codex use by default?
A: GPT-5 is used by default, and the reasoning level can be adjusted.
Q: Is there a dedicated model for Codex?
A: Yes, mainly codex-1 (cloud) and codex-mini-latest (CLI low latency version).
Q: Can o3 and o4-mini be used with Codex?
A: Yes, they work together in CLI workflows, but codex-1 is more recommended for complex tasks.
