GPT-5.2 o1 vs Codex CLI
A detailed comparison to help you choose the right AI tool for your needs.
Our Pick
GPT-5.2 Thinking
GPT-5.2 Thinking edges out Codex CLI with superior overall performance and features that make it the better choice for most users.
Try GPT-5.2 o1Feature Comparison
Feature
GPT-5.2 o1
Codex CLI
Ratings
Overall Rating
4.9
4.7
Coding
4.8
4.7
Writing
4.5
4.3
Reasoning
5.0
4.5
Speed
3.8
4.6
Value
4.0
4.8
Pricing
Monthly Price
$200
$20
Free Tier
Input (per 1M tokens)
$15
$2.5
Output (per 1M tokens)
$60
$10
Features
Context Window
128K
128K
Vision/Images
Audio
Video
Code Generation
AI Agents
GPT-5.2 Thinking
Pros
- Best reasoning model from OpenAI
- Edges out Gemini 3 and Claude Opus 4.5 on most tests
- Performs at/above human expert level on GDPval
- Excellent for coding, math, and document analysis
- State-of-the-art on SWE-Bench Pro
Cons
- Expensive ($200/mo for Pro subscription)
- Slower than Instant variant
- Requires Pro subscription for full access
- Writing can feel robotic
Codex CLI
Pros
- Open source (Apache 2.0)
- Multimodal input support
- Local-first privacy
- Rich approvals workflow
- Included with ChatGPT subscription
Cons
- Newer tool with evolving features
- Less mature than Claude Code
Choose GPT-5.2 o1 if you need:
Complex reasoning, software engineering, research, math proofs
Choose Codex CLI if you need:
Rapid prototyping, open-source flexibility, ChatGPT users
Ready to get started?
Both tools offer free tiers or trials. Try them out and see which one works best for your workflow.