I want to org-capture (or something like it) to a non org file, in particular a bibtex file.

In more detail

If point is in an org-file in a link of the shape [myurl][mydescription] And I call org-capture, I want

• a prompt for a key
• An entry of the shape

  @online{prompted-key
    url   = {myurl};
    title = {mydescription}
}

to get appended to some designated .bib file