git tag -a HEAD leads to ambiguous branch name

[git@xxxxxxxx]

Good evening,
today I encountered a warning using  git version 2.39.0.windows.2:
/warning: refname 'HEAD' is ambiguous./
It turned out, having written
/git tag -a HEAD -m "Some message."/
was the culprit.
As
/git branch HEAD/
yields the following error
/fatal: 'HEAD' is not a valid branch name/
I wanted to aks, whether a similar check should  be applied to tag names.
Best regards
Johannes Wilde