MC1387806: Anthropic Claude Fable 5 available in Copilot Cowork (Frontier)
Anthropic Claude Fable 5 (preview) is now available as an opt-in, admin-controlled model in Microsoft 365 Copilot Cowork (Frontier) for complex tasks. It requires data retention by Anthropic under separate terms. Admins must enable and manage access, ensuring compliance with data retention and pr...
[What and Why]
We’re expanding model choice in Microsoft 365 Copilot so you can pick the right model for the job. Claude Fable 5 (preview) is available as a default-off option in Copilot Cowork (Frontier), with limited private preview extensibility in Copilot in Excel and PowerPoint.
This model is designed to support longer, more complex tasks such as multi-step knowledge work, coding, and visual reasoning.
Claude Fable 5 is off by default and admin controlled. Unlike other models currently available in Microsoft 365 Copilot, this model requires data retention by the model provider Anthropic and is subject to Anthropic terms. Organizations can choose whether and how to enable the model to evaluate these advanced capabilities.
[Rollout Schedule]
- Frontier Preview (opt-in): Beginning in early June 2026 and expected to complete in early June 2026.
- Availability may vary by region and tenant configuration.
Note: Frontier is an opt-in private and public preview program.
[Impact on your organization]
Who is affected
- Admins managing Microsoft 365 Copilot
- Users in tenants where the model is enabled
Platforms/Services
- Microsoft 365 Copilot
- Copilot Cowork (Frontier)
What will happen
- Claude Fable 5 is off by default and must be explicitly enabled by an admin.
- Admins can enable the model and scope access to specific users or groups.
- This model is a preview model with data retention.
- When enabled, users will see the message: “Some models require data retention: your prompts and responses are retained by the model provider."
- Data used with this model is retained by Anthropic as an independent processor.
- Use of this model is subject to Anthropic terms, Data Protection Addendum, and data retention practices for Mythos-class models.
- No changes to data handling for other Microsoft 365 Copilot models.
- This model is intended for evaluation and experimentation, not production use.
[Action required / recommendations]
No action is required if you do not plan to enable this model.
If you plan to enable Claude Fable 5 (Preview):
- Review your organization’s compliance, privacy, and data retention requirements.
- Evaluate whether preview models with data retention meet your governance policies.
- Enable the model in the Microsoft 365 admin center and scope access appropriately.
- Communicate the data retention behavior and implications to users before enabling.
- Update internal documentation and helpdesk guidance.
Learn more:
- Anthropic models in Microsoft Online Services | Microsoft Support
- Get Started with Frontier | Microsoft Frontier
- Microsoft 365 Copilot release notes | Microsoft 365 Copilot | Microsoft 365 | Microsoft Learn
- Preview AI models in Microsoft Online Services | Microsoft Support
[Compliance considerations]
| Question | Answer |
| Does the change store new customer data, if so, where, and is the data cached or permanently stored? | Yes. Prompts and responses are retained by Anthropic for this preview model as part of its data retention requirements. |
| Does the change alter how existing customer data is processed, stored, or accessed (such as documents, emails, chats, etc.), if so how and to what extent? | Yes. Data is processed and stored by Anthropic as an independent processor under separate terms, rather than under Microsoft’s standard data processing model. |
| Does the change introduce or significantly modify AI/ML or agent capabilities that interact with or provide access to customer data, if so summarize changes? | Yes. This change introduces a new AI model with distinct processing and data retention characteristics compared to other models available in Microsoft 365 Copilot. |
| Does the change provide end users any new way of interacting with generative AI, if so how? | Yes. Users can select and use an additional AI model within Microsoft 365 Copilot experiences when enabled by an admin. |
| Does the change add any integration to third-party software products, and if so what? | Yes. Admins must explicitly enable the model and can scope access to specific users or groups. |