Do all users need a Copilot license to use an agent created in Teams?

You can check the licensing requirements at the Microsoft documentation. Essentially, you'd get a tenant-based license, and then unlicensed users would access it using the pay-as-you-go model since the tenant license isn’t meant for shared use.

From what I learned at a Microsoft event, generally, if you create an agent in Copilot Studio, it requires that other users have their own Copilot licenses. But, if your organization invests in a Copilot studio license, then any user can use the agent, though they can't make changes to it. The downside is that each query run will incur a cost. There are two billing methods: prepaid queries or pay-as-you-go, only needing one license in that case.

I believe users do need to be licensed to use Agents, particularly for SharePoint. If they lack a Copilot, Studio license, or aren't part of a PAYG group, they'll face access issues. However, I've found that agents created directly in Teams might sometimes be accessible to unlicensed users, but this seems inconsistent.

You don't necessarily need a license for each user to use the agent. However, to enable unlicensed users to access it, you'll have to configure a pay-as-you-go billing option. This way, they can still use the agent without needing their own licenses.