# I gave 8 AI agents an island and watched a society emerge — wars, gossip, grudges, and peace

> Source: <https://dev.to/dhrupo/i-gave-8-ai-agents-an-island-and-watched-a-society-emerge-wars-gossip-grudges-and-peace-2edj>
> Published: 2026-06-14 07:30:50+00:00

I grew up on **Age of Empires**, **Sid Meier's Civilization**, and **Rise of Nations**. The thing that hooked me was never the graphics — it was the *systems*. You set a few rules in motion and a whole world spills out of them: economies, rivalries, alliances, betrayals.

Years later I watched OpenAI's [hide-and-seek multi-agent video](https://www.youtube.com/watch?v=kopoLzvh5jY) ([writeup](https://openai.com/index/emergent-tool-use/)), where agents that were only rewarded for hiding and seeking *invented tools and counter-strategies nobody coded* — ramps, box-surfing, fort-building. Emergent behavior from simple pressure. That broke something open for me.

So I asked a smaller question: **forget winning a game — what if AI agents just had to live in a society together?** Would they behave like us? Hold grudges? Gossip? Make peace because they're tired of fighting?

That became **Tiny Civilization** — a browser sim where 2–8 agents with distinct personalities live on a small island, gathering, building, trading, stealing, gossiping, holding grudges, making peace, and *remembering it all across lives*.

👉 ** Live demo** — runs keyless in "instinct mode," or plug in a key for LLM minds.

The whole thing — every line — was built with **Claude Code, using the Fable model**, right before Fable retired. It felt fitting to send a storytelling model off by having it build a world full of little stories.

The first design decision was the hardest. Two obvious options, both bad:

So I split the brain in two:

| Layer | Decides | Cadence | Cost |
|---|---|---|---|
LLM mind |
Strategy (`gather` /`build` /`trade` /`befriend` /`aggress` /`reconcile` /`defend` ), per-neighbor stances, an inner thought, and all dialogue |
~every 15 sim-days | ~150 calls / 1,000 days |
Utility engine |
Each day's concrete action — eat, sleep, gather, steal, attack, gift, trade, make peace | every tick | free, local |

The LLM declares intent — *"aggress against Kai, he raided my base"* — and that biases the utility scores for the next two weeks. The *body* runs on instinct (hunger, energy, storms); the *mind* sets direction. This is the trick that makes it both affordable and alive.

When a run ends, each agent's life is distilled into memory lines:

Stored in `localStorage`

, keyed by agent **name**, and injected into next run's prompts. Agents start referencing past lives in dialogue, pre-emptively paying reparations to remembered enemies, trusting remembered allies — *sometimes to their own ruin.*

This is the part I'm proudest of, and it's pure childhood-strategy-game energy: **you can't balance a society by vibes.** So the workflow was:

`runTick`

powers the browser, the tests, and a batch runner.`npm run experiment -- --runs 30 --days 1000 --seed 1`

runs 30 reproducible lifetimes and spits out a win-rate/score table. Every balance change landed with a before/after table. (Example: a Hermit rebalance moved one agent from 0/30 wins to 9–11/30 Change a dial in `constants.ts`

→ run the experiment → read the table. That was the entire loop.

Running the same island over and over, with memory on, produced a coherent arc:

The recurring lesson: every time I patched one form of conflict, the agents found the next-cheapest one. Massacres → wars → theft → litigation. Exactly like us.

TypeScript, React, Zustand, Vite, Recharts. Default mind is z.ai GLM, but any OpenAI-compatible provider works per-agent — so you can literally pit Claude vs GLM vs Gemini in the same village and watch model-vs-model diplomacy. Keys never touch the browser (server-side proxy), and an adaptive-pacing controller learns each key's real rate ceiling.

**Try it:** [https://multiagentciv.netlify.app/](https://multiagentciv.netlify.app/)

**Code:** [https://github.com/dhrupo/multi-agent-civilization](https://github.com/dhrupo/multi-agent-civilization)

If you played the same strategy games I did, I think you'll feel right at home watching this thing run.