Use the Record Dependency Settings when creating a message action to define compatibility and ensure the action only appears in appropriate situations.

First, choose a Record Dependency Type:

• Single Record Only - Action only works for a single record.
• Record Collections Only - Action only works for multiple records.
• Both (One or More Records) - Works for single or multiple records.
• No Record Dependency - Action has no dependency on a related record.

Note: Flow actions currently only support "Single Record" and "No Record" types.

Next, select compatible data types or choose "Any Data Type". 

Here is an example for an action that launches a flow to convert a lead. The flow can only convert one lead at a time, so we'll select "Single Records (Only)". The flow only works with Lead records, so we'll deselect "Any Data Type" and select "Lead" from the list of available options:

Admins and developers can activate additional data types for message actions as needed.