Can AI help with a FET file? What we found
We put an AI assistant next to the FET file check. It finds the FET rule for what you describe. Here is what it does well, and where it fails.
Blog Importing from FET
Blog
Tricks, tutorials and worked examples for building timetables.
Importing from FET Next term, start from this one: clone it or merge it Clone a timetable to start a new term, or bring only the standing rules into another one. What travels, what stays behind, and how to go back. 
The constraint that makes your FET timetable impossible
One wrong constraint can make a FET file impossible, and the search can run for hours before you know. Check the file first. It is free and takes seconds.
A group, a year, a subgroup — which one did you mean?
The vocabulary that stops new FET users in their tracks, explained with an actual school instead of a definition list.
Two shifts, one building
Half your school arrives at seven and leaves at noon. The other half arrives at noon. Most timetabling tools quietly assume you are one school.
Will it give me my file back?
Your .fet file is a term of work. Before you hand it to any tool, there is one question worth asking — and one two-minute test that answers it.