Microsoft Copilot: Choose Claude as Your AI Model

Microsoft 365 Copilot no longer runs exclusively on OpenAI's GPT models. Since June 2026, organizations can activate Anthropic's Claude as an alternative AI model. This means you pick the model that fits the task.

What changed?

Microsoft introduced model selection in Microsoft 365 Copilot in June 2026. Alongside the default GPT model, Anthropic's Claude is now available -- in Copilot Chat, Word, Excel, PowerPoint, and the new Copilot Cowork. Since July 2, 2026, Claude Sonnet 5 is available, and as of mid-July, GPT-5.6 serves as the new default alongside Claude as the alternative.

The key point: model selection costs nothing extra. Claude is included in the existing Copilot license ($30 per user per month).

Why does this matter?

Different AI models have different strengths. GPT excels at native Microsoft 365 integration -- it seamlessly accesses emails, calendars, Teams chats, and SharePoint. Claude is stronger at complex analysis, document understanding, and structured text generation.

In practice: for 'Summarize my last ten emails,' GPT is the better choice because it directly accesses Outlook. For 'Analyze this 80-page contract and find all clauses that put us at a disadvantage,' Claude may be the better pick.

How to enable Claude in your organization:

Step 1 -- Admin activation (IT department):

1. Open Microsoft 365 Admin Center
2. Settings -> Copilot -> Data Access -> AI Providers
3. Enable Anthropic

Without this activation, users will not see the model picker.

Step 2 -- Select the model (as a user):

1. Open Copilot in a supported app (Copilot Chat, Word, Excel, PowerPoint)
2. A dropdown menu appears in the upper-right corner of the Copilot pane
3. By default it shows 'Auto' (Microsoft chooses the model)
4. Click the dropdown and select 'Claude'
5. You can switch between models between prompts as often as you like

Where Claude is available:

- Copilot Chat: General queries, analysis, writing, summaries
- Word: Create, rewrite, and structure documents
- Excel: Generate formulas, analyze data, transform tables
- PowerPoint: Create slides, structure content
- Researcher: Deep research sessions with Claude Opus
- Copilot Cowork: Multi-step tasks across multiple Microsoft 365 apps

Copilot Cowork -- the new agent mode:

Alongside the Claude integration, Microsoft made Copilot Cowork generally available. Cowork is not a chat -- it is an agent: you assign a complex task, and Copilot works through it independently, across multiple apps, files, and data sources.

Example: 'Create a PowerPoint presentation with commentary from the quarterly figures in the Excel file and send it as a draft to my team.' Cowork opens the Excel file, creates the presentation, writes the commentary, and prepares the email.

Cowork uses Anthropic's models by default (Opus 4.8 and Sonnet 4.6). You can also choose GPT.

When to use Claude, when GPT?

| Task | Recommendation |
|---|---|
| Summarize emails | GPT (better Outlook integration) |
| Analyze long documents | Claude (stronger document understanding) |
| Summarize Teams meetings | GPT (native Teams connection) |
| Review a contract | Claude (precise text analysis) |
| Create Excel formulas | Both work equally well |
| Build a presentation from data | Claude (structured output) |
| SharePoint search | GPT (deeper Graph integration) |

Rule of thumb: if the task relies heavily on Microsoft data (emails, calendar, Teams), choose GPT. If the task primarily requires text understanding and analysis, try Claude.

Privacy note:

This is critical: Claude requests are currently not processed within the EU Data Boundary. All Claude processing runs on US servers. This affects organizations that rely on Microsoft's EU Data Boundary.

What this means:

- When you use Claude in Copilot, your data leaves the EU
- GPT requests stay within the EU Data Boundary (if your tenant is configured accordingly)
- For GDPR-sensitive tasks (employee data, customer data, health data), GPT is currently the safer choice
- In the UK, Claude is disabled by default and requires an explicit admin opt-in decision

Recommendation: Talk to your IT department before using Claude for business-critical or privacy-sensitive tasks. For general productivity tasks without sensitive data, Claude is a valuable addition.

Practical tips:

- Test both models: Ask the same question once with GPT and once with Claude. The differences in style and depth are often surprising
- Use 'Auto' as default: Auto mode lets Microsoft decide which model fits the task better. Switch manually when you want to test a specific model
- Claude for analysis sessions: When working through a long document, set Claude and stick with it. This avoids context switching
- GPT for everyday work: For quick tasks in the Microsoft ecosystem (drafting emails, meeting summaries, calendar planning), GPT remains the more seamless choice

Availability:

- Requirement: Microsoft 365 Copilot license ($30/user/month)
- Plans: Business Standard/Premium, E3, E5, E7
- Cost for Claude: No additional cost
- Admin activation: Required
- Rollout: Worldwide since June 2026

Assessment: Model selection in Microsoft 365 Copilot is a fundamental shift. For the first time, different AI providers compete directly within the same productivity software. For users, this means more control: you are no longer locked into one model but can choose what works best for each task. The most important caveat remains data privacy -- as long as Claude processing does not happen within the EU Data Boundary, organizations handling sensitive data need to be cautious.

Sources: microsoft.com/en-us/microsoft-365/blog/2026/06/16/copilot-cowork-is-now-generally-available, learn.microsoft.com/en-us/microsoft-365/copilot/copilot-anthropic-apps