Game-Dev

TL;DR Last time I wrote about giving my Ultima Online shard’s NPCs a voice, a memory, and a small autonomous life. That post ended with “the peasant talks back now.” In the eight days since, the project grew six new systems: NPCs keep daily routines anchored to real places, every town runs a rumor board that traveling NPCs physically carry between cities, townsfolk gossip about players (your katana, your karma, your reputation), the GM avatar got actual powers governed by a genie rule, villagers hand out delivery quests, and a population director keeps every city stocked with 200 ambient “denizens” who hail you in the street. That’s ~3,200 new NPCs and maybe a dozen new LLM call sites, still running entirely on a local gemma-class model — the trick is that the model never gained a single new permission. Every new capability is deterministic code; the LLM still only ever produces words and picks verbs off allowlists. Also: I found out my RAG pipeline had been silently dead for days, and the lesson there is worth the price of admission. ...

TL;DR I run an Ultima Online shard on my homelab where the NPCs are driven by a local LLM instead of canned dialog trees. Each NPC rolls a persisted identity, remembers conversations with individual players across reboots, runs its own errands and cross-map journeys, and — the part I’m writing about today — strikes up ambient chatter with nearby NPCs on its own. The newest work extends all of that from townsfolk to language-speaking monsters: ogres, lizardmen, ratmen, gargoyles, daemons, and especially liches, who address each other like god-kings deigning to notice an insect. Inference is a local gemma-class model behind an in-cluster gateway, so it’s free and private, with the one tradeoff being cold-load latency. It’s single-shard hobby-scale and it absolutely shows the seams. I love it. ...

TL;DR I open-sourced the integration that puts a local LLM behind the NPCs on my Ultima Online (ServUO) shard. It’s about 7,500 lines of C# that drop into a shard’s Scripts/Custom/ directory and compile at boot — no separate build, no service to deploy. This post is the code-level companion to the story version of the project: how config hot-reloads, how the model client marshals async results back onto the game thread, how the LLM is kept entirely out of the simulation loop, and how a deterministic allowlist makes a non-deterministic model safe to put in a stateful world. The whole thing is fail-open: if the model is slow, down, or wrong, the NPC silently degrades to a vanilla ServUO NPC. Code is on GitHub: ZoltyMat/uo-llm-npc. ...