Access to Office App Context and Setting CEA as Default in Microsoft 365 Copilot

Hello everyone,

I’m exploring **Custom Engine Agents (CEA) in Microsoft 365 Copilot** and have two questions regarding their integration with Microsoft 365 applications.

### 1. Can a Custom Engine Agent access the current Office application context?

When a CEA is added to Microsoft 365 Copilot, is there a supported way for the CEA to access the content of the Office 365 application where Copilot is currently being used?

For example:

- **Word:** Can the CEA read and/or modify the document currently open in Word?

- **Outlook:** Can the CEA access the current email/thread and perform write operations such as drafting or modifying content?

- **PowerPoint:** Can the CEA access and modify the presentation currently open?

- Similarly, other Microsoft 365 applications where Copilot is available.

Essentially, I’m trying to understand whether a **Custom Engine Agent can leverage the same application context and read/write capabilities that the native Microsoft 365 Copilot has within these applications**.

If this is supported, what APIs, SDKs, or integration patterns should be used?

### 2. Can a Custom Engine Agent be configured as the default mode?

Is there a supported way to:

- Disable or bypass the default Microsoft 365 Copilot experience/mode, and

- Configure a **Custom Engine Agent as the default agent/mode** that users interact with when they open Copilot?

For example, if an organization has a custom agent that should handle the majority of Copilot interactions, can that agent be configured as the default instead of the standard Microsoft 365 Copilot?

I’d appreciate any clarification on the current capabilities, limitations, or recommended architecture for these scenarios.

Thanks