Task Manager: Require Attachment Before Marking Task as "Prepared"

Hi everyone,

We have a requirement from our business users to make it mandatory to attach supporting documentation to certain tasks before they can be marked as "Prepared" in Task Manager.

We reached out to OneStream Support, and they confirmed this isn't supported out-of-the-box. They did advise that we could accomplish this by leveraging Business Rules or Event Handlers.

Has anyone in the community encountered this request and successfully solved it? If so, we would love to hear your approach. Specifically:

• Which Event Handler type did you find works best for intercepting a Task Manager status change?
• Do you have any code snippets for checking if a file attachment exists on a specific task?
• Are there any performance impacts or pitfalls to watch out for when implementing this?

Thanks in advance for any insights or examples!