Microsoft 365 Copilot: xAI Grok 4.1 Fast now available in Copilot Studio for US customers (admin opt-in required)

Starting February 19, 2026, xAI Grok 4.1 Fast, a text-only large language model, will be available in Microsoft Copilot Studio for U.S. customers by admin opt-in. It is disabled by default, hosted outside Microsoft environments, and governed by xAI’s terms, requiring review of compliance before enabling.

[Introduction]

Starting February 19, 2026, xAI Grok 4.1 Fast will be available as an optional large language model within Microsoft Copilot Studio for customers in the United States. Grok 4.1 Fast is a text‑only model and will join the existing model catalog that includes OpenAI and Anthropic models. Because Grok is provided by xAI, an external model provider, it will be disabled by default and will require a tenant-wide admin opt‑in before use.

This change will give organizations additional model choice and flexibility for agent orchestration within Copilot Studio.

[When this will happen]

Preview: Available in February 2026 for U.S. customers whose admins decide to enable the feature.

[How this affects your organization]

Who is affected

Admins who manage Microsoft Copilot Studio and govern AI model availability for their tenant.

What will happen

• Grok 4.1 Fast will appear in Microsoft Copilot Studio as an available model option (after opt-in).
• The model will remain disabled by default until an admin opts in.
• After the model is enabled, makers will be able to select Grok 4.1 Fast as the primary AI model for agent orchestration.
• Admins will be able to manage Grok model availability in:
  • Microsoft admin center (MAC)
  • Power Platform admin center (PPAC)

Important: Grok models are hosted by xAI outside of Microsoft-managed environments. Data used with Grok is processed outside of Microsoft’s compliance and audit boundaries. This means Microsoft Product Terms, Data Protection Addendum, data residency commitments (EUDB) do not apply to use of xAI models. Instead, your use is governed by xAI’s Terms of Service and Data Processing Addendum. 

[What you can do to prepare]

If you intend to allow use of Grok 4.1 Fast in your tenant:

• Review your data governance, security, and compliance requirements before enabling external models.
• Use one of the following admin centers to opt in:
  • Microsoft admin center: Enable external models
  • Power Platform admin center: Allow external language models for generative responses
• Communicate to makers or helpdesk staff that Grok 4.1 Fast is optional and will only become available if enabled by an admin.
• Update internal documentation if you track approved LLMs or external model usage.

If you do not want users to access Grok models, no action is required.

Learn more: 

• Allow external language models for generative responses | Power Platform | Microsoft Learn
• Select a primary AI model for your agent | Microsoft Copilot Studio | Microsoft Learn
• xAI's Data Processing Addendum
• xAI’s Terms of Service