[RPG] How does barkskin work

Now the wording in the spell description is extremely vague and ambiguous making the spell effect up for interpretation.

It just says:

… the target's AC can't be less than 16, regardless of what kind of armor it is wearing.

Right off the bat you have to ask what AC is it referring to? Total AC, Base AC or just armor AC?

Now from the text you would be inclined to think it refers to armor AC since that's the only reference that's included in the text.

So in other words on interpretation could be that unless you are wearing an armor that equals or exceeds 16, such as full plate, your armor now have an armor AC of 16.

However the description mention the target's AC and not the armor's AC so a more likely interpretation would be that unless you are wearing an armor that equals or exceeds 16 your total AC is 16. So regardless if you run around in leather armor or buck naked you have an AC of 16.

But that just brings modifiers into the questions.

Like can you add you dex bonus to AC like you do to you base AC?

Now unlike the Mage Armor spell the Barkskin's spell description doesn't mention any dex bonus so a strict interpretation of the rules as they are written would say no.
Fair enough Barkskin apparently doesn't just make you look like a tree it also makes you stiff as one too. (Which in all honestly is a kind of cool flavor effect, though I doubt it was intentional.)

Yet that makes things very strange when you get characters with very high dexterity.

A character with maxed out dex will have a total AC 15 if he/she runs around naked which means the Barkskin spell will improve his/hers armor. However, if that character puts on any armor its AC will equal or exceed the 16 which means if you interpret the description literally that the spell no longer has any effect. So then you wonder why it mentions armor in the way it does?

And it gets even stranger if you start adding other modifiers like that from shields for example.

If the buck naked maxed out dex character picks up a shield its AC suddenly is 17 which invalidates barkskin.

But that's not the weird thing because that's probably the wrong interpretation of how Barkskin works.

Because since the spell description doesn't mention modifiers, dex bonus or otherwise, a literal interpretation is that once you cast the spell your AC is 16 regardless of modifiers.

Which means that Barkskin invalidates the existence of shields. In other words while under the effect of Barkskin it doesn't matter if you use a shield or not unless it pushes your total AC over 16.

The same is true for any feat, such as dual wielder or defensive duelist, or other effect, such as evasive footwork, that in some way modifies your AC.

In fact a strict interpretation of Barkskin as written has the spell invalidating every single rule about how AC is calculated and modified. Use the Barkskin and your AC is 16, no more or less regardless how skilled, agile or equipped your character is. Unless of course you manage to get a better AC which in all honestly is kind of hard not to do.

Now all this seems freaking weird because the result is that Barkskin breaks the spirit of the rules if not the letter.
Because instead of treating AC as the total sum of a character's skills, abilities and equipment Barkskin treats AC as a condition. Cast the spell and you have the condition of having AC 16, unless you break the spell.

And all because the wording of the spelldescription is so vauge.

Which has me asking if this is the way Barkskin really is meant to work?