Most NPCs in most games are a menu. You walk up, you get the same four lines, you walk away. The illusion holds for about ninety seconds.
I wanted something else: characters who act on their own, notice you, and still be there — still remembering — the next time you log in.
An NPC is an actor, not a script
The load-bearing decision is architectural rather than conversational. In Mudiverse, an NPC is a real actor type. When one of them walks from the galley to the bar, that movement is resolved by the same command processor, against the same room and exit data, under the same rules that resolve your movement. There is no separate "NPC mover" that cheats.
That matters for a reason that is easy to miss. A scripted NPC can teleport, walk through a locked door, or hand you an item that never existed, because nothing is checking. An NPC that goes through the command queue can't do any of those things — the same validation that stops you stops them.
The AI proposes; deterministic code validates and clamps before anything is written. The model is never the thing holding the world together.
Memory is notes, not transcripts
When you talk to a character, they may write something down. Not a log of the conversation — a note. A short, subjective line in their own words about what they took from the exchange.
This turns out to be much better than a transcript, in both directions:
- It's cheap enough to keep forever. A transcript of every conversation with every player is a cost problem and a context-window problem. A handful of notes is neither.
- It's more true to a person. You don't remember what someone said to you last spring. You remember that they were rude about the shipping fee. The note is the part that survived, which is exactly what memory is.
It also produces the occasional perfect moment. A player once gestured at paying for a shelf of goods — described the act, without actually spending anything. The bartender didn't play along; nothing moved, because nothing had moved. Later, in her notes, the incident showed up as "gestured payment for shelf." Dry, accurate, and slightly unflattering. She had filed it.
What a described action is worth
You can act — describe what your character does, in the third person. act bows deeply to the room.
An act changes nothing. It writes one message and touches no state. That's what makes it safe to hand a free-text verb to anyone.
The interesting problem is what the AI characters do with it, because a described action is a submission, not a fact. If you announce that you are flying around the room as king of the world, an NPC that answers "Your Majesty!" has destroyed the setting in a single line. So they don't. They dismiss it, in character, dryly, and — this took a fix to get right — they stay dismissive on later turns. An NPC's own uncertainty is never evidence that the impossible thing might be real.
The honest limit
Here is the part that would be easy to leave out.
Nothing moves in an empty room. NPC turns fire when a player is present to see them. The world is not out there simulating itself while you sleep, and I'd rather say that plainly than let anyone discover it and feel misled.
Within a room you're standing in, though, the characters are genuinely going about their business — walking their circuits, wiping down counters, declining to be impressed by you.
Mudiverse is pre-alpha: playable, actively being built, not launched.