What this model error usually means
Mistral: Mistral Medium 3.1 returning 400 / context length exceeded means you should first confirm whether model ID mistralai/mistral-medium-3.1 is visible for this Mistral AI key, then separate permission, context, capability, rate limit, or route issues.
- Model: mistralai/mistral-medium-3.1
- Provider: Mistral AI
- Status code: 400