GPT-5.6 Luna Pro vs Mistral Medium 3.5
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 GPT-5.6 Luna Pro and Mistral Medium 3.5.
GPT-5.6 Luna Pro
GPT-5.6 Luna Pro is the same underlying model as [GPT-5.6 Luna](https://openrouter.ai/openai/gpt-5.6-luna), served with `reasoning.mode` set to `pro` for higher-quality responses on complex tasks. Learn more in OpenAI's docs: https://developers.openai.com/api/docs/guides/reasoning#reasoning-mode
Mistral Medium 3.5
Mistral Medium 3.5 is a dense 128B instruction-following model from Mistral AI. It supports text and image inputs with text output, and is designed for agentic workflows, coding, and complex...
Technical Specifications
| Specification | GPT-5.6 Luna Pro | Mistral Medium 3.5 |
|---|---|---|
| Provider | OpenAI | Mistral |
| Context Window | 1,050,000 tokens | 262,144 tokens |
| Agent Suitability | N/A | N/A |
| Time to First Token (TTFT) | N/A | N/A |
| Deployment Model | managed api | self hostable |
| Production Stability | beta | stable |
| API Available | Yes | Yes |
| Released Date | 2026-07-09 | 2026-04-30 |
API Pricing Comparison
Input Price per Million Tokens
GPT-5.6 Luna Pro
$1.00
Mistral Medium 3.5
$1.50
Output Price per Million Tokens
GPT-5.6 Luna Pro
$6.00
Mistral Medium 3.5
$7.50
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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.
GPT-5.6 Luna Pro Quirks & Gotchas
No developer gotchas reported.
Mistral Medium 3.5 Quirks & Gotchas
No developer gotchas reported.