Use Case: Enforce the completion of Checklist Items before a Taskfeed Task can be marked as completed or dragged to the Complete list.
This functionality is possible with some Salesforce customization by defining a validation rule on the Taskfeed Task object in Salesforce Setup.
Salesforce User Permissions Needed
To view field validation rules: View Setup and Configuration
To define or change field validation rules: Customize Application
Define a New Validation Rule:
Navigate to Setup.
Click Object Manager in Lightning Experience or select Create > Objects in Classic, then select the Taskfeed Task object.
Select Validation Rules.
Enter a Name and use the following Error Conditioning Formula:
(taskfeed1__Completed_Checklist_Items__c < taskfeed1__Checklist_Items__c)
Enter an Error Message, define any other properties and click Save.