With the Apex REST integration with API Catalog, which is now generally available, you can bring Apex APIs into your API catalog. In your Apex code or by using API Catalog, you can activate and make invocable and agent actions available to use.
Where: This change applies to Lightning Experience in Developer, Enterprise, Performance, and Unlimited Editions.
How: Deploy an Apex REST class for an API that's activated for use in Agentforce. The deployment automatically adds the OpenAPI document and associated metadata to your API catalog. If your code includes tags to activate API actions, the deployment activates the actions. You can also activate and deactivate actions by using API Catalog. View the Apex APIs in the Apex list view in the catalog.