Table of Contents
Summary
- GPT-5 is now the default model for Microsoft 365 Copilot, with three reasoning modes: Auto, Quick response, and Think deeper.
- Users can select their preferred mode, and their choice will be remembered for future chats.
- A new selector will appear in Copilot experiences, enabling mode changes without admin intervention.
- The feature is enabled by default for all users, with no required actions for administrators or users.
Admin Impact: Low
User Impact: Low
Release Start: 04 Dec 2025
Release End: 08 Dec 2025
Services: M365 Copilot Chat
Category: Plan for change
Tags: New Feature, User Adoption, Admin Action
History
12/4/2025 Item Added to Message Center
Microsoft Message
As announced in MC1176368 (October ’25) GPT-5 is now the default model and today we’re introducing the ability for your users to select how much reasoning to apply.
Users can choose from three modes:
- Auto (default): Copilot decides how long to think.
- Quick response (chat): Copilot answers right away.
- Think deeper (reasoning): Copilot thinks longer for better answers.
This change is associated with Microsoft 365 Roadmap ID: 532736
When this will happen
General Availability (Worldwide): Rollout will begin December 4, 2025, and we expect to complete by December 8, 2025.
How this affects your organization
Who is affected: All users of Microsoft 365 Copilot.
What will happen:
- Users will see a new selector in Copilot experiences.
- Default mode is Auto; users can switch to Quick response or Think deeper.
- User’s choice is remembered and retained for new chats.
- No admin configuration changes required. There are no admin controls for this feature.
- Feature is enabled by default for all tenants.
What you can do to prepare
- No action required; this is a standard rollout.
- Optional: Communicate the new modes to helpdesk staff and users.
Compliance considerations
No compliance impacts identified. Review your organization’s policies as needed.