Procgen city sim with the LLM as director (not content generator) — am I reinventing the wheel? Anyone done this before?
Curious to hear from this crowd. I'm chewing on an architecture and want to know what I'm missing — prior art, failure stories, related work, anything.
The idea. Procedural simulation is the load-bearing core and is always sufficient on its own. The LLM, when present, doesn't generate content directly — it directs the procgen by translating open-ended natural language or random world events into parameters the engine can already act on. Two modes:
- Director. GM types "gold has been struck in the eastern hills." (or indeed the event engine forces the LLM to come up with an interesting event) The LLM receives the current state of the world and returns the shape of the gold rush — spawn coordinates, accelerated growth rate, characteristic service mix (brothels and taverns before smithies), demographic skew (transient single males, weapons-carry up, organised crime within 6 months), spillover on neighbours. The procgen then applies all of it deterministically.
- Flavourer. Engine produces a deterministic NPC with all the facts (parents, work history, debts, ownership chain). The LLM prosifies those facts into bio + voice + secrets. Never invents new facts, only narrates.
Why bother with the LLM at all. Pure procgen is rigid — you can pre-code plague mechanics, but you can't pre-code "the harvest god has died" or "a foreign queen visits" or "a comet is read as an omen of war." Those need cultural/symbolic reasoning. The LLM provides it, then steps out of the way. The engine stays deterministic and runs fine with the LLM off.
Context (briefly). I'm building this for a tabletop RPG city sim — the headline interaction is "who is at the inn at 2pm on a Tuesday, and why?" — but the architecture pattern feels more general than that, which is why I'm asking here rather than in r/RPGdesign.
Asks (broad on purpose):
- Have you seen this pattern — LLM as director rather than generator — used anywhere? Games, sims, worldbuilding tools, weird hobby experiments, anything.
- Is there a name for this when it's been done? "AI-Directed Procedural Generation" is my working term, happy to use whatever the field already calls it.
- War stories from anyone who's tried LLM-in-the-loop with procgen — what broke, what worked, what surprised you?
- Reading list — papers, blog posts, postmortems, side projects. Anything I should know about before I commit to this direction.
Genuinely just trying to learn what's out there before I go heads-down. Happy to share more detail in comments.