It's not clear why, but it looks like tconstruct tags have all vanished from all tool pieces. Unless I'm misunderstanding, and they were never there; but I seem to remember having a variety of choices for tags for different swords/axes, etc. Other tags, like those for tools, appear to still exist. tconstruct:parts still exists.

it looks like there weren't actually tags for the pieces because they're actually all the same tool piece, just with different NBT. however, on a related issue, the tags for the casts for tinkers archery and constructs armory were messed up, and eventually led to datapack related crashes. This has been fixed.