Validating list key

YANG
2

If you have something like this:

$ pyang -f tree utilities.yang
module: utilities
   +--rw utilities
   |  +--rw utility* [utility-name]
   |     +--rw utility-name     utility-enumeration
   |     +--rw util-a-config
            your must() expression here
   |        +--rw some-util-config
   |           +--rw some-util?   string

$ confd_cli -u admin -C
admin connected from 127.0.0.1
# devtools true
# config       
Entering configuration mode terminal
# utilities utility util-a-enum util-a-config some-util-config some-util test
# pwd
Current submode path:
  utilities utility util-a-enum
# xpath must "current()/utility-name = 'util-a-enum'"                        
true

I.e. your must expression could be something like must "current()/../utility-name = 'util-a-enum'"

And as @waitai replied to you some time ago: