# Markets (`mttr_markets`)

Updated October 24, 2026.

## What does mttr_markets do?

Groups of sites close in meaning, each named by the site at its centre, largest first. A site in a market writes about the same work as the others in it. Only whoever runs this mttr may make this call.

Who may call it: Owner.

## When to use it

- You want to see how the sites read fall into lines of work.

## What you ask

You might say: “What markets has mttr found?”

```
mttr_markets({})
```

## What comes back

- Each market with the site at its centre and how many sites it holds.

A sample, with made-up sites and figures:

| Market, by its centre | Sites |
| --- | --- |
| north.example | 64 |
| rival.example | 41 |
| shop.example | 18 |

## Over HTTP

```
curl "https://mttr.si/api/v1/markets" \
  -H "Authorization: Bearer $MTTR_KEY"
```

## When it fails

| When | Status | What to do |
| --- | --- | --- |
| Your assistant has no key yet | 401 over MCP | Sign up with `mttr_signup`, then connect again with the key it gives. |
| The key is a person’s, not the owner’s | 403 | Nothing: only whoever runs mttr makes this call. |

## Sources

- [Model Context Protocol: tools](https://modelcontextprotocol.io/specification/2025-06-18/server/tools), Model Context Protocol: How an assistant calls a tool.

The call in full: [mttr_markets in the API reference](https://mttr.si/docs/reference#mttr_markets).

## Goes with

- [A site against its market](https://mttr.si/docs/tools/market.md)
- [Nearest sites](https://mttr.si/docs/tools/near.md)