Test your startup idea on a crowd of AI customers

What it is

MiroFish is an open-source "swarm intelligence" engine (82,000+ stars on GitHub, AGPL-3.0). You give it your idea, a pitch deck or a prototype description. It builds a small digital world of AI people, each with a personality, a backstory, memory and opinions. They talk about your idea on a simulated social network. Then you get a report on what the crowd thought and why, and you can chat with any one of them.

What you need

the Claude desktop app with Claude Code;
about 20 minutes;
an API key for any OpenAI-compatible model provider (MiroFish runs its AI people on it, so it uses tokens);
a Zep Cloud API key (MiroFish uses it for the AI people's memory).
Claude installs the rest for you: Node.js 18+, Python 3.11–3.12 and uv.

Steps

Step 1. Make a folder

Create a folder called MiroFish. In the Claude app, open the Code tab and choose that folder.

Step 2. Paste this into Claude

Install MiroFish from https://github.com/666ghj/MiroFish in this folder.
Check that Node.js 18+, Python 3.11 or 3.12 and uv are installed. If anything is missing, tell me what you'll install and wait for my OK.
Copy .env.example to .env and open it for me. I'll paste my own keys into LLM_API_KEY, LLM_BASE_URL, LLM_MODEL_NAME and ZEP_API_KEY. Wait until I say "done".
Then run npm run setup:all and npm run dev, and open http://localhost:3000 when it's ready.
Explain each step in one short line.

Step 3. Run your first simulation

Upload your pitch (a PDF or plain text works). Write the question you want answered, for example: "Would freelance designers pay $19 a month for this?" Start small: a few agents and a few rounds. It's faster and uses fewer tokens.

Step 4. Read the report and ask questions

Open the report: who liked it, who passed, and why. Then pick any AI person and ask them directly: "What would make you pay for this?"

Good to know

Treat it as a focus group, not a crystal ball. Use it to find objections early.
Change one thing (price, headline, audience) and run it again to compare.
Bigger simulations cost more tokens. Scale up only when the small one is useful.

You need the Claude desktop app with Claude Code (any paid plan, Pro is enough). For setup we recommend Opus 5.5.