MCP server

Our MCP server opens the population model to anything that speaks the Model Context Protocol over HTTP: an agent framework, a workflow tool, a product of your own. This page is the reference for wiring it in. Setting up a chat client? Getting started is shorter. Building a product on Hiasynth? Start with Builder.

The server

Connecting and listing tools is free, and so is the attribute catalogue. Running a tool spends credits from the account the connection belongs to. There is no separate developer tier: the subscription on your Hiasynth account is what unlocks the tools, for every client and every key on it.

Authenticating

OAuth is the right choice for anything with a user and a browser. The server publishes its metadata at the standard well-known locations, supports client ID metadata documents, and falls back to dynamic client registration, so a compliant MCP client needs nothing but the address. The user signs in on hiasynth.co, sees which app is asking and where it will be sent back, and approves. Tokens are per user, per client, and can be revoked from the user's connector page.

API keys are for anything without a browser: scripts, cron jobs, a server-side agent. Create one under API keys on your connector page, and send it as a bearer token on every request. A key is shown once, can be labelled, and can be revoked at any time.

Authorization: Bearer YOUR_API_KEY

A key acts as the account that created it. Keep it server-side; never ship it in a client.

Configuring a client

Most JSON-configured clients take the server like this:

{
  "mcpServers": {
    "hiasynth": {
      "url": "https://mcp.hiasynth.co",
      "headers": { "Authorization": "Bearer YOUR_API_KEY" }
    }
  }
}

Drop the headers block for clients that sign in with OAuth. Claude Code:

claude mcp add --transport http hiasynth https://mcp.hiasynth.co

The tools

Nine tools, all read-only and idempotent. The nine tools lists what each one takes in, hands back and costs, and what you see there is what tools/list returns. Every tool answers with aggregates calibrated to official statistics. Nothing returns a person. list_attributes is the authoritative catalogue, and reading it is free.

Every tool also takes a place: a name in plain language, a NUTS or ISO code, or a point with radius_km. Name one and answers come back in seconds. Places and geography has the detail.

Credits and limits

A subscription carries a monthly allowance; credit packs sit behind it and never expire. The account owner sees the balance on their home page and can set a low-credit email under account settings. When an account has no active subscription, tool calls answer with a short message saying so, rather than an error, so an agent can surface it to the user. All tools are read-only and idempotent; retrying a failed call is safe.

For your model

The published docs are also available as plain markdown for language models: /llms.txt lists them, and every page has a .md twin, for example /docs/build.md.