Export VCF header

I wrote a VCF with hl.export_vcf, and all of the FORMAT fields have empty descriptions:

##FORMAT=<ID=AD,Number=.,Type=Integer,Description="">
##FORMAT=<ID=DP,Number=1,Type=Integer,Description="">
##FORMAT=<ID=GQ,Number=1,Type=Integer,Description="">
##FORMAT=<ID=GT,Number=1,Type=String,Description="">
##FORMAT=<ID=MIN_DP,Number=1,Type=Integer,Description="">
##FORMAT=<ID=PGT,Number=1,Type=String,Description="">
##FORMAT=<ID=PID,Number=1,Type=String,Description="">
##FORMAT=<ID=PL,Number=.,Type=Integer,Description="">
##FORMAT=<ID=SB,Number=.,Type=Integer,Description="">

Is this expected? Do I need to include these fields in my metadata dictionary?

yeah, Hail doesn’t have any default descriptions.

Metadata is the way to go, sorry.