Microsoft Copilot Studio: Mistral Medium 3.5 will be available (admin opt-in required)

Microsoft Copilot Studio will add Mistral Medium 3.5 as an external AI model option, disabled by default and requiring admin opt-in. Available from May 2026, it offers more flexibility for agent orchestration, with existing governance and compliance controls maintained. No user impact unless enabled by admins. What and Why Microsoft Copilot Studio is introducing support for Mistral Medium 3.5. This update will provide customers with more flexibility to select models that best meet their business needs for agent orchestration and generative AI scenarios. External models such as Mistral remain disabled by default and require admin opt-in, ensuring administrators maintain control over model usage, data access, and compliance. Rollout Schedule Public Preview: Rollout begins at the end of May 2026. Impact on Your Organization Who is affected Admins managing Microsoft Copilot Studio Organizations building or managing agents in Microsoft Copilot Studio Platforms/Services Microsoft Copilot Studio Microsoft admin center Power Platform admin center What will happen Mistral Medium 3.5 will be available as a selectable model in Copilot Studio for supported environments. The model will be included in the multi-model selection experience for agent orchestration. External models, including Mistral, will be disabled by default. Admins will need to enable external models at the tenant level before use. Makers will be able to select Mistral Medium 3.5 after admin enablement. Existing policies and governance controls will continue to apply. There will be no impact to users or workflows unless admins enable external models. Action Required / Recommendations No action is required unless you plan to enable this feature. If you choose to enable Mistral Medium 3.5: Review external model configuration in your tenant Enable external models in the Microsoft admin center. Review: Connect to xAI’s models | Microsoft Learn Configure permissions and governance in the Power Platform admin center. Review: Allow external language models for generative responses | Microsoft Learn Communicate this change to makers using Copilot Studio. Update internal governance or AI usage policies if applicable. Learn more:  Connect to xAI’s models | Microsoft 365 Copilot | Microsoft 365 | Microsoft Learn Allow external language models for generative responses | Microsoft Learn Mistral Medium 3.5 […]

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