GPT-5.2 Codex vs Claude 3 Opus

1. Optimized for Long-Horizon Coding Tasks

• OpenAI describes GPT-5.2 Codex as a highly intelligent coding model built for long-horizon, agentic coding work.
• Well suited to planning, refactoring, debugging, and multi-step implementation flows inside real codebases.

2. Adjustable Reasoning for Coding Work

• Supports configurable reasoning effort from low to xhigh depending on speed and quality needs.
• Accepts both text and image inputs while producing text output.

3. Large Context + Long Output

• 400 k token context window supports broad repository understanding and larger working sets.
• Allows up to 128 k output tokens for longer patches, code generation, and technical explanations.

4. Up-to-Date Model Snapshot

• Knowledge cut-off of Aug 31 2025 keeps it current with newer tools and frameworks.
• Supports streaming, function calling, and structured outputs for tool-driven coding workflows.

1. Intelligence & Reasoning

• Highest capability in the Claude 3 family
• Near-human comprehension and fluency
• Excels at MMLU, GPQA, GSM8K, advanced reasoning tasks

2. Complex Problem Solving

• Best for research, strategy, multi-step planning
• Handles ambiguous, open-ended tasks with ease

3. Vision & Multimodal Capabilities

• Strong chart/graph understanding
• Processes documents, technical diagrams, and dense visual data

4. Recall & Long-Context Reasoning

• Near-perfect recall (>99% on NIAH benchmark)
• Handles very large documents and multi-file workflows

5. Enterprise-Grade Accuracy

• Significantly reduced hallucinations
• High correctness rate for factual queries