They are fine with corals, just no other inverts like shrimp, crabs, snails, etc. The mantis will kill them.
If it isn't a coral the mantis will go after it. TBH, I wouldn't put anything other than softies with a mantis. Sloppy eaters, just like eels, make keeping pristine water difficult. I also believe mantis don't like a strong flow that sps need anyway.