Claude Opus 4.6 vs GPT-5.1-Codex
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for Claude Opus 4.6 and GPT-5.1-Codex.
Claude Opus 4.6
Opus 4.6 is Anthropic’s strongest model for coding and long-running professional tasks. It is built for agents that operate across entire workflows rather than single prompts, making it especially effective...
GPT-5.1-Codex
GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows. It is designed for both interactive development sessions and long, independent execution of complex engineering tasks....
Technical Specifications
| Specification | Claude Opus 4.6 | GPT-5.1-Codex |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Context Window | 1,000,000 tokens | 400,000 tokens |
| Agent Suitability | 95/100 | N/A |
| Time to First Token (TTFT) | 500 ms | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2026-02-04 | 2025-11-13 |
API Pricing Comparison
Input Price per Million Tokens
Claude Opus 4.6
$5.00
GPT-5.1-Codex
$1.25
Output Price per Million Tokens
Claude Opus 4.6
$25.00
GPT-5.1-Codex
$10.00
Want to test both models live?
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
Claude Opus 4.6 Quirks & Gotchas
- ▸Best for long-context document analysis and legal review
- ▸Tool calling requires structured prompt — prone to verbose refusal without explicit output schema
GPT-5.1-Codex Quirks & Gotchas
No developer gotchas reported.