There's a couple references to Writing Tools and Apple Intelligence. https://developer.apple.com/search/?q=%22writing%20tools%22&type=Documentation
That being said, I don't think anything is actually available in the first developer beta.
"Apple Intelligence will be available in an upcoming beta this summer." - https://developer.apple.com/apple-intelligence/
danx
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution