I'm not here to argue about the tag system or where the line gets drawn between lore tags and general tags.
I am here to suggest that within the current 'tag what you see' way of doing things, gender tagging gets pretty case by case to such an extent that justifying a tag solely off what bits the character in question has doesn't really help anyone.
For example:
Female reptilian/draconic/ect characters with a vulva/slit, but no breasts under 'tag what you see' could easily qualify as andromorphs. Most are accurately tagged female, because the species specific context is generally understood alongside creator intention. I have no problem with this, but I bring it up as an example of nuance within gender tagging.
Likewise,
If a femboy character is drawn with smaller a-cups while having a penis, it would make the most sense for those searching for art of characters like that for it to be tagged male. This is despite the fact that a character with breasts (size unspecified) and a penis could fall under many tags (gynomorph, herm, intersex) depending on the tagger's interpretation.
Let's say im looking for female/male posts. It would not be helpful for a post with a character who has breasts and a vulva BUT is referred to within image dialogue with masculine pronouns to be tagged female/male. In most cases, this is due to character lore with the particular character being trans. Even ignoring this, it would be more effective to tag the appropriate physical markers (breasts, vulva) while excluding the female/male tag.
Asking how defined the chest of an andromorph character has to be before they get categorized as female when other characters with no breasts so to speak are tagged female (calling back to my reptile example) is purely subjective.
I would personally suggest the addition of an androgynous or otherwise gender tag, but the exclusion of a gender tag entirely when best applicable could also work.
Again, I have to make it very clear I am not against the tag what you see rule. I just think it would benefit everyone's user experience to exercise even a little nuance regarding gender tags.