Does Mindless limit my minions' ability to help build our kingdom?

Question

I'm currently about to join a game where we use the kingdom building and downtime rules to run a growing kingdom.

My character idea is a necromancer who uses their undead as a form of labor, making them build and perform menial tasks.

The issue I am running into though is I don't know what the actual limit of the undead are. They are mindless and thus have no skill points, but for example, can the necromancer give them orders to build something if they provide enough details? Are they stuck with just carrying stuff around and making things easier for living workers?

What are the limits to mindless beings used for labor tasks?

If there isn't an official ruling on this, what are other mindless beings used for in official settings? I believe I remember a setting where golems were used to build houses and maintain them, both are mindless so if the golems can do it I would say undead could as well. Please provide sources and names of settings if you use them in your answers.

I have looked up the Unseen Servant questions as well but due to the nature of the spell and how it lists tasks the Servant can do, unlike with undead spells such as Animate Dead which only details some combat stuff you can order them to do. The two are related but different enough.

Answer 1

Officially, you are better with a Lyre of Building than trying to find rules for undead laborer to build towns. The topic of wether mindless creatures can take simple orders or not is subject to GM fiat and normally will see table variation.

Now, if you happen to be interested on what Jason Nelson, the creator of the original kingdom building system for the Kingmaker AP, has designed for undead workers, you should take a look on the Ultimate Ruleship (3rd party book from Legendary Games). Which, among other things that improve the kingdom building system, brings some magical improvements like the Deathless Laborers, Animated Automation (animated objects as laborers), Hallow/Unhallow (to cast permanent spells on a building) and Permanent Teleportation Circle (exactly what the name says):

Deathless Laborers (2 BP per building or 10 BP per hex):

While incapable of skilled labor, mindless undead created with animate dead are utterly tireless in performing simple, repetitive tasks. Animated skeletons and zombies can be created and tasked to perform such simple labor, increasing economic productivity but making the general populace nervous about the possibility of the undead breaking loose and going on a rampage against the living. Effect Infamy +1. Deathless laborers in a city must be assigned to a specific building that provides a bonus to Productivity. They provide the following additional settlement modifiers: Economy +1, Productivity +1, Danger +1.

Alternatively, deathless laborers can be assigned to a hex with a Farm, Mine, Quarry, or Sawmill; undead in these hexes provide +1 additional BP of revenue (or increase Consumption reduction of a Farm by 1), while creating +1 Unrest and increasing Danger in that hex by 5.

Prerequisite Caster’s Tower or Temple; Tunnels or Graveyard.

As for your question: Yes, it does limit their work.

By how much: That's up to your GM.

Some GM's will say that mindless creatures cannot do anything related to math, or measure distance, or measure weight. Others will say that they can do anything as long as you explain it properly. While others will say that they can do anything as long as they are being supervised and directed, as long as someone with the proper Profession or Craft skill is directing them.

Crafting a simple item (like a spoon) is a DC 5 Craft check, while crafting something a little more complex (like an iron pot) is a DC 10 craft check. Considering that mindless creatures make Int-based checks with a +0 bonus, and that Craft can be used untrained, that means they could craft simple items with a take 10 on their skill check. If they have the proper tools (at least +2 bonus), they could even make simple weapons, like long bows and short swords, or leather armors and shields.

Answer 2

The PPC: Black Markets splat features the availability of undead slaves, and has this to say:

Unscrupulous business owners sometimes use mindless undead laborers. Mindless undead also make good soldiers and exceptional guards, as they attack without concern for their personal welfare. A standard human zombie costs about 90 gp, while a skeleton costs 45 gp, although most necromancers charge an additional fee of 50 to 100 gp to provide a body, and purchasers are expected to provide their own means of controlling their shambling laborers.

So it is clear that the use of undead servants for labour is fully supported, officially. When it comes to what they are actually capable of, mindless creatures have no skills or feats, but the Craft skills may be used untrained. Mindless creatures also have no intelligence score, but therefore simply make intelligence-based checks with a +0 modifier. They're the very definition of unskilled labor. If a task could be readily done by someone with no experience and no training but no signficant mental impairment besides a lack of free will and independence, your undead laborers can do it. Not as quickly as a skilled living laborer, but they work longer hours, at least. I would interpret that you probably want a non-mindless skilled worker to supervise them and give orders if you're doing anything more complicated than building a wall in a straight line, but they could do that just fine.