The documentation for autocompletion of citations within TeXShop appears to be fragmented around the web. The default suggestion is to use a service from BibDesk, but this requires BibDesk to be open. I don't use BibDesk and I don't want to keep selecting the correct .bib file.
Is there a standard way to accomplish this without BibDesk? I see from this decade-old discussion that there were some applescripts to accomplish this, so it's at least possible.