Microsoft 365 Copilot now defaults to GPT-5 with a mode selector offering Auto, Quick response, and Think deeper options. The rollout begins December 3, 2025, affecting all users with no admin changes needed. User mode choices persist across chats and the feature is enabled by default.
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
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.
- No action required; this is a standard rollout.
- Optional: Communicate the new modes to helpdesk staff and users.
No compliance impacts identified. Review your organization’s policies as needed.