Licensing with custom Copilot Studio agent

Question

I want to build an Outlook add-in app that will proofread your email. I'm trying to use Copilot Studio to build a custom agent with specific logic that will do the proofreading. The user won't directly work with Copilot, it would just be a side window where the user would click a button that would send the text of the email to the agent and it would get back what the agent generated.

More context:
I would be using Node.js, Yeoman, Outlook Add-In Framework (Office.js) to create the add-in.
It would be specifically for people at my company, so we would deploy it through the Microsoft 365 Admin Center for the company.
The add-in app would send an api request to the agent to send and receive text? (not sure yet)

Questions:
Would the users need individual Copilot licensing? It's a "custom engine agent" and they're not using it directly. Everyone has the basic copilot chat (used to be Bing chat?) but not everyone has Copilot Studio license.
I was thinking it would be kind of like a customer service q&a chat bot, and customers don't need any licensing for that, which I thought was the whole point of Copilot Studio. It will only be text that's being sent back and forth so it won't be an issue with usage cost either?

Answer 1

Hi Hamin Han ,

Thank you for your inquiry regarding the integration of a custom Copilot Studio agent within an Outlook add-in for internal use. Please find below the clarifications based on Microsoft’s current licensing and deployment model:

User Licensing Requirements: Users interacting with the Copilot Studio agent indirectly via the Outlook add-in are not required to have individual Copilot Studio licenses. This is because the interaction occurs through a backend service (the add-in), not the Copilot Studio UI. The agent functions like a customer-facing chatbot, where end-user licenses are not necessary.

However, if users do not have Microsoft 365 Copilot licenses, message-based billing will apply under the Copilot Studio consumption model.

Billing Model: Copilot Studio provides two options for billing message consumption:

Message Packs: Prepaid 25,000 messages per tenant/month at $200/month.

  **Pay-as-you-go (PAYG)**: $0.01 per message sent/received.
  
  These charges apply to all user interactions without Microsoft 365 Copilot licenses, even when accessed indirectly through the add-in.
  
  **Deployment and Integration:** Your planned approach using **Node.js**, **Yeoman**, and **Office.js** for building the Outlook add-in is supported. The add-in can securely pass email content to the Copilot Studio agent via API and return the processed response.
  
  Key requirements:
  
     Ensure the agent is published and accessible via a secure endpoint.
     
        Confirm that Copilot Studio metering is enabled in the **Power Platform Admin Center** to track and manage usage.
        
        **Summary:**
        

Aspect	Requirement/Status
Direct user license	Not required for indirect add-in access
Direct user license	Not required for indirect add-in access
Microsoft 365 Copilot	Optional; reduces billing if available
Billing model	Message-based (Message Packs or PAYG)
Agent authoring	Requires Copilot Studio author license
Deployment	Supported via Microsoft 365 Admin Center

Thanks,  

Karan Shewale  

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