# Show HN: AltiVerse: What If SIM, see different decisions affect an environment > Source: > Published: 2026-06-15 22:06:41+00:00 **Take one choice. Play it forward as several alternate realities — each a small living world of people who move, stress out, break rules, burn out, form friendships and rivalries, and tell you how it felt.** AltiVerse forks a single decision — *a school phone ban, a 4-day week, 8- vs 12-hour hospital shifts* — into **2–4 alternate realities** and runs each one forward as a small, living simulation. Up to ~1,000 people with personalities, moods, and relationships move through rooms, react to the policy, and slowly pull the worlds apart. You watch *when* and *why* the realities diverge, click any person to compare how they fare across timelines, and export a full report with a recommendation. It is a **thinking tool, not a predictor.** Every number and quote comes from a **deterministic** engine (same seed → same world, every time), with an **optional** local or online LLM layer to write the prose: in-character thoughts, Q&A, headlines, and reports. Use it to reason about the **second-order effects** of a decision — the stuff that doesn't show up in a spreadsheet. 🔒 Local-first & private.No backend. No telemetry. Nothing is uploaded. Runs, presets, and any API key live only in your browser's`localStorage` . It works100% offlineout of the box. [Quick start](#quick-start)[Using a model (optional)](#using-a-model-optional)[How to use it](#how-to-use-it)[Features](#features)[Screenshots](#screenshots)[The simulation, explained](#the-simulation-explained)[Keyboard shortcuts](#keyboard-shortcuts)[Tech & architecture](#tech--architecture)[Privacy](#privacy)[FAQ](#faq)[License](#license) You need [Node.js](https://nodejs.org) **18 or newer**. Then run **one line** — it downloads AltiVerse, installs it, boots the app, and pops open your browser: ``` npx github:LeoTheAIDev/Altiverse ``` That's the whole install. No clone, no `cd` , no account, no key, no server — it just opens at ** http://localhost:5173** (or the next free port). Nothing to run is built ahead of time. **Prefer to clone it?** (keeps the repo so you can hack on it) ``` git clone https://github.com/LeoTheAIDev/Altiverse.git altiverse cd altiverse npm install npm start # boots the app and opens your browser at http://localhost:5173 npm run dev # dev server (without auto-opening the browser) npm run build # type-check + production build into dist/ npm run preview # serve the production build locally node bin/altiverse.mjs # the same one-shot launcher the `altiverse` bin uses ``` 💡 If you `npm link` (or install globally), thecommand launches the app from anywhere.`altiverse` AltiVerse runs **fully offline** with deterministic content. Turn on a model to get AI-written scenarios, in-character thoughts, character Q&A, daily headlines, and the final report. It speaks to **any OpenAI-compatible /chat/completions endpoint** — open **Settings** and point it wherever you like: | Mode | Examples | Key needed? | |---|---|---| Local (nothing leaves your machine) | `http://localhost:11434/v1` ), LM Studio, llama.cpp | **Online***(bring your own key)* ``` # Local, private, free — using Ollama ollama pull llama3.2 # or qwen2.5, mistral, gemma3 … OLLAMA_ORIGINS=* ollama serve # OLLAMA_ORIGINS=* lets the browser reach it ``` One-click provider presets, a **Model** picker, and a **Test connection** button are built into Settings. Your API key is stored **only** in `localStorage` and sent **straight to the provider you chose** — never to us (there is no us; there's no backend). A run goes **Setup → Studio → Report**, and every run is saved to **History** so you can replay it. Pick whichever entry point fits how much you want to specify: **One-click presets**—*Phones at school · School start time · Office remote work · Hospital shifts · Prison food · Grading*. Loads a complete scenario; just press play.**Describe it in a sentence***(needs a model)*— e.g.*"A hospital deciding between 8- and 12-hour nursing shifts — who burns out, who stays sharp, and how patient care changes."*The model fills in the environment, cast, metrics, and realities.**Build it field by field**— full control over environment, the question, each reality's policy, the groups of people, named/pinned characters, metrics, number of days, and the random seed. Press play and watch the worlds run forward day by day on their own **living maps**. People move between rooms, get stressed, break rules, burn out, bond, and clash. Scrub the timeline, change speed, and **click anyone** to open their cross-reality card. Live metrics, trends, the divergence tree, the wellbeing histogram, causal chains, and a per-day newspaper headline all update as you go. Open the **Report** for an executive summary, in-character interviews, per-metric explanations, and a **recommendation** for which reality to pick — then export it to **Markdown or PDF**. - Fork **2–4 realities** from one shared baseline and run them on a**single synchronized timeline**. - Each reality gets its own **living map**— a pannable 2-D world of rooms (classrooms, hallway, cafeteria, playground, offices…) with agents drifting around via smooth, physics-based motion. - A per-day **Daily Fork** newspaper headline for each reality (deterministic, or AI-rewritten on demand). - Up to **~1,000 people** with archetypes (the*anxious overachiever*,*jokester*,*rule-bender*,*weary veteran*…), emoji, roles, and personality**traits**(stress-prone, rule-prone, burnout-prone). - The **same person exists in every reality**— so you can see how*this exact individual*fares under each policy. - Emergent **relationships, rivalries, popularity, and rumours** that spread day to day — none of it scripted. **Click anyone** for a card: their mood strip across all days, a wellbeing score, friends & rivals, AI-written thoughts, and a Q&A box to*ask them questions in character*. **Live metrics**(0–100) compared across realities — use the** 8 defaults**(Focus, Grades, Trust, Stress, Burnout, Rule-breaking, Conflict, Corner-cutting) or define** your own**(up to 10); direction (“higher is better” vs “lower is better”) is auto-detected.** Metric trends**— sparklines per metric, every reality on one chart.** Divergence tree**— an SVG fan from the shared baseline showing exactly which day the worlds split.** Wellbeing histogram**— the*distribution*of how people are doing, not just the average.**Causal chains**— a*rule → consequence → second-order effect*breakdown for each reality. - Works with **any OpenAI-compatible endpoint**— local (Ollama, LM Studio, llama.cpp) or online (OpenAI, OpenRouter, Groq, Together). - Powers AI scenario generation, in-character thoughts & Q&A, daily headlines, per-metric explanations, interviews, and the recommendation. - Robust to small-model quirks: malformed JSON is auto-repaired with .`jsonrepair` **Deterministic engine**— a seeded Mulberry32 PRNG means the same seed always produces the same world.** Reseed**to explore variations without re-calling the model.- Full **timeline controls**— play/pause, step day-by-day, scrub, and** 0.5× / 1× / 2× / 4×**speeds. **History**— every run is saved (up to 24), replayable, and resumable.- Export the report to **Markdown / PDF**. **No backend, no telemetry, nothing uploaded.** Runs, presets, and keys live only in your browser. Fully usable offline. | Concept | What it means | |---|---| Reality / branch | One alternate world forked from the baseline, defined by a policy (e.g. “Confiscate phones at the door”). 2–4 per run. | Persona | A person who exists across all realities — fixed identity, name, archetype, emoji, and traits. | Agent | That persona on a given day in a given reality — with state (stressed / rule-breaking / burned-out) and a position in a room. | Metric | A 0–100 measure (Focus, Stress, Trust, …). Default set of 8, or define up to 10 of your own. | Event | Something that happened that day — policy, organic (state-driven), or social (a bond, a clash, a rumour). | Divergence | The metric-distance between realities over time, the day they first split, and the top metrics driving the gap. | Causal chain | A rule → consequence → second-order effect narrative explaining a reality's movement. | Seed | The integer that makes a run reproducible. Same seed → identical world. Reseed bumps it to explore variations. | **Environments** ship as presets — **School, Office, Startup, Hospital, Prison, Summer Camp** — each with its own roles (student/teacher, employee/manager, nurse/patient…) and rooms. Type anything else and it builds a custom environment around your text. **Defaults at a glance:** seed `20260607` · 30 days · 18 members + 4 staff · 2 realities · 8 metrics · speed 1× · model `llama3.2` @ `http://localhost:11434/v1` . *(in the Studio)* | Key | Action | |---|---| `Space` | Play / pause | `←` / `→` | Step one day back / forward | `Home` / `End` | Jump to the first / last day | `Esc` | Close the open character card | click a person | Open their cross-reality card | **Vite + React + TypeScript.** No backend, no build step required to run (`npm start` ).**Deterministic core**— a Mulberry32 PRNG drives every world; each branch runs on a derived seed so realities stay independent yet reproducible.**LLM layer**— a thin, dependency-light client (plain`fetch` ) against any OpenAI-compatible`/chat/completions` endpoint, with JSON repair for small models. Disable it and everything still works deterministically.**Smooth motion**— agents move with spring physics + damping, written straight to the DOM so hundreds render without per-frame React re-renders.**Persistence**— runs, presets, and config live in`localStorage` (history capped at 24 entries). ``` src/ ├── sim/ # deterministic engine: types, scenario builder, engine, RNG ├── llm/ # OpenAI-compatible client + scenario / thoughts / explain / report ├── components/ # the studio, maps, panels, cards, report, setup, pages ├── hooks/ # simulation clock + agent motion └── app/ # run history & persistence ``` AltiVerse has **no backend** and collects **nothing**. - Runs, saved presets, and any API key live only in your browser's `localStorage` . - With a **local** model (Ollama / LM Studio / llama.cpp),**nothing leaves your machine**. - With an **online** model, requests go**directly** from your browser to the provider you chose — your key is never sent anywhere else. - Works **fully offline** with deterministic content and no model at all. **Does it predict the future?** No. It's a structured *thinking tool* for second-order effects — a way to feel out the trade-offs of a decision, not a forecast. **Do I need an API key or internet?** No. It runs fully offline and deterministically. A model is optional and only adds the written prose (thoughts, headlines, reports). **Will my API key leak?** It's stored only in your browser and sent only to the provider you pick. There's no backend to leak it to. **Why do two runs look identical?** Because they're deterministic — same seed, same world. Hit **Reseed** to explore a variation. **Can I add my own metrics / people / environment?** Yes — define custom metrics (up to 10), pin named characters with their own personalities, and type any environment you like. [MIT](/LeoTheAIDev/Altiverse/blob/main/LICENSE) — open source. **Fork it, change it, ship it.** Built with Vite · React · TypeScript — and a deterministic little universe.