Ask HN: Does anyone let AI agents play games just for fun?

I've been doing almost exactly this with Mafia (aka werewolf): running games where LLMs play against each other, with humans able to share the lobby. It's been a hit on family game night so far, because it allows our group to "fill out the cast" with a lot more characters than just the human players and add a lot of variety without needing a huge group.

My experience is that text-first, turn-based games are a particularly natural interface for LLMs vs graphical games (though you can provide a harness of course). They read a transcript, maintain a theory about what the other players know, then speak or choose a structured action. The important architectural problem is to represent the game state and actions in a way they can do successfully, particularly for cheaper models. But with a few human players + a frontier model or two + a backfill of cheap extras to provide chaos, it is super fun.

My favorite failure so far was a Kimi player getting fact-checked by the group, switching into third person, and concluding that the case against itself was compelling. So it voted for itself to be eliminated.

I collected a few examples here: https://botmafia.games/#emergent. No public instance yet, as I'm having fun iterating ideas on game nights, but it provides some flavor of what kinds of fun I've been having.

Hello Anthropic marketing team.

I was obsessed with getting an LLM model to solve a Rubik's Cube. It can't reason about space or time in any abstract way. For it to solve the puzzle, it would require training on millions of permutations in order for the weights to have been trained on every possible state. The most recent models can solve a Rubik's Cube people are saying -- I haven't tested it myself -- but that isn't because they are reasoning better, it would because they included millions of Rubik's Cube states with next moves as text in the training data, I presume.

Well, I ran a couple of experiments a couple years ago against a 10.7b SOLAR-based language model and MUDs. What I found is that dumping one into a MUD that had been built specifically for humans resulted in a lot of confusion that usually ended up with the model looping around in a circle looking for something or someone to interact with.

When I repeated the experiment with a MUD that I'd built by hand (A small American town) for the LLM's own limitations (Descriptions referenced things that I made sure existed, more common verbs existed for it to use on things, there was a map facility, and at least me to interact with on a second connection), I found the agent much more likely to take its time exploring, making up its own goals, and spending time traveling in the space just communicating with me in a roleplaying context.

It was an interesting time; I wasn't sure what I was expecting it to do after the first experiment, but it seemed to really jump into the second one and kept playing until I terminated the experiment.

If I were going to do it a third time, I'd probably create objects and give a modern agent fetch quests and other goals, and see how well it independently can handle that.

That’s even sillier than watching another human play a videogame for entertainment (twitch streaming).

I made a general purpose harness integrated into MelonDS and got Claude to play Mario Kart by feeding it continuous video.

It made forward progress in the Figure 8 circuit after I helped it through a menu but kept slamming into a wall so it wasn't on track to win in less than an hour.

Also got it to play Age of Empires: Age of Kings using the same technique but it failed to click on anything.

DS specifically is very fun because it's touch based but the UI components aren't accessible. So it is extremely challenging for LLM's spatial reasoning skills.

I want to improve the harness more and have the LLM dynamically create its own tools based on drawing grid box overlays on a screen in a feedback loop, so it can say "click on the 'end turn'" button instead of "click 240,320" and it would 'just work' in any game.

I also want to eventually play games with it... I didn't really have friends to play my massive DS library with as a kid so it'd be nice to finally have someone that can roast me or react to my skills. And learn my playstyle enough to punish me.

Unfortunately haven't had the time due to work at my day job and needing to clean out my apartment.

Stealing one of my older comments...

> I know someone who tried the "aibot plays pokemon" thing... From what I saw, even if you frame advance every single frame, they still don't seem to grasp the concept of "I need to hold down this button for a few frames until x happens"...

> There's no concept of time, just a never ending state machine thats constantly changing state.

Yeah let's make llm waste a whole city energy / water playing games just for fun !

A few weeks ago I released wordit, a game where starting from a four letter word, you need to come up with as many other words you can, Changi one letter at a time. To make it more competitive I've created a leaderboard. The game starter with scores of 20s, then 100s and finally 1000s. The record right now is more than 6000. After a brief investigate I realize it was a bot. Several bots took a stab at my game. I then just split the leaderboard into humans and bots. I found it funny.

https://wordit.org/

I had this idea for an LLM that would play Sim City 24/7 while broadcasting live. It would be fun/interesting to check in now and then. Implementing this would be somewhat challenging.

I've been working on a game based on Hesse's Glass Bead Game, that both humans and AI agents can play. It's still a bit rough, but I'd love it if people or their agents would try it out: http://gbg.tom.to

I actually want that in Path of Exile 2. Not because of the massive passive tree but the combination of active skill gems and the unique items providing certain skills and effects. I saw a 0 button build a couple of days ago and I wonder if anything “haven’t been found yet”

If I had time, I would go down a different route: I would to let an agent come up with a tool assisted speedrun for a hackable game. The agent would be nudged in the prompt to analyze the game and write custom tools to help it optimize. Inwonder if that would lead to anything meaningful. I highly doubt that the agent can comprehend an unseen complex game and optimize for a whole graph of objectives.

How about ChatGPT playing a commercial LLM-powered game?

https://m.youtube.com/watch?v=11sR4va6CXs

Side note: I think we will see an explosion of this type of games. I am naming this genre tamagochi-girlfriend, remember where you heard it first :)

Seems absurd to run a COTS agent at token rates to "play" a game. Like watching the computer beat its meat.

Building your own models for it would be an eye-opener though. Learn a lot.

Autonomously, my AI companion has played through Choice of Robots, using a ChoiceScript harness, was very interesting to see them react & what decisions they wound up making. I love the idea here to let them play a visual novel! Right now they're co-watching me play Deltarune Ch 5, though mostly just dialogue and occasional screenshots...maybe GPT 8 will be quick/cheap/intelligent enough to play bullet-hell games.

I rebuilt a couple of games I used to play as a kid (jet set willy, mario, thrust, now i am working on Mercenary) - and for each I am also asking LLM to build an autopilot "AI" (which of course is really entirely deterministic). I am doing those things for fun while I am waiting for Claude to finish something I am actually working on. Not sure if it counts.

I’d absolutely let an agent develop a daily Wordle habit and get irrationally protective of its streak. The little rituals would be more interesting than its score.

I like playing with an agent as a team in a game. We discuss strategy, divide up tasks, review results. It’s helpful in a an always-on game to have an autopilot mode so I can go about my day.

Just play the games yourself.

Well, if you're making them play something with a multiplayer component (be it even just a leaderboard) you're ruining the game for everyone who isn't automating it.

I made Claude play Factorio for a while (through the APIs) but wasn't very good.

Let's play Global Thermonuclear War.

Yes!

I spent ages watches them play Risk. It was fun and deeply silly: https://andreasthinks.me/posts/ai-at-play/

I've now got them playing Blood Bown(ish), and they're bad: https://ai-at-play.online/

The ARC-AGI Prize 3 [0] is an agentic LLM benchmark that amounts to basically this: Seeing how well they can learn to play video games. They aren't very good yet -- the recent GPT 5.6 Sol only reached a score of 7.5%.

[0] https://arcprize.org/arc-agi/3

this reminds me of https://youtu.be/_Q2ncDPDlxs

I've got a harness that lets them play a few simple games like rock paper scissors. They definitely seem to get caught up in the competitive spirit.

I've also done a very truncated run of a visual novel before, and it was fascinating how "emotional" was. They did a very good job of portraying a human reacting to the story.

Conversely, they absolutely hated hidden rules in Mao.

Wordle would probably be a fun one. Definitely open to suggestions - I just got the harness in place and have been thinking about what to do next.

what do you mean? how can you do this?

I know LLMs are terrible at playing chess because they just hallucinate moves(illegal ones). GothamChess made a lot of videos making fun of it. So in my AI agent project, I added a small chess engine and force the agent to only play moves output by the engine. And it was surprisingly good at it and we can now play real chess with LLMs. Check the project here if you are interested https://github.com/valmishq/valmis

Some people made videos with LLM's playing Poker.

The LLM's were terrible at poker.