# Compare two sites (`mttr_compare`)

Updated October 24, 2026.

## What does mttr_compare do?

Two sites already read, rule by rule: the scores and stages side by side, and the rules each is ahead or behind on by the share of its pages passing. With view set to content, their pages by meaning instead. A key may make this call on the sites it has claimed.

Who may call it: Your claimed sites.

## When to use it

- You want to know where a rival does better.
- You want to see what two sites both write about.

## What you ask

You might say: “Compare example.com with rival.example.”

```
mttr_compare({ site: "example.com", with: "rival.example" })
```

| Argument | Type | Needed | What it is |
| --- | --- | --- | --- |
| `site` | Text | Yes | The site, as a domain such as example.com. |
| `with` | Text | Yes | The other site, as a domain already read. |
| `view` | One of these: rules, content | No | rules (the default) or content. |

## What comes back

- Both scores and their stages.
- Each rule with the share of pages passing on each side.
- By content: pages both write about, and what only one does.
- The other site must have been read as well, named as with; a site set against itself is refused.

A sample, with made-up sites and figures:

| Rule | example.com (72) | rival.example (66) |
| --- | --- | --- |
| Show sources on guides | 70% | 95% |
| Answer the first question right under it | 81% | 40% |
| Add a tap-to-call link | 64% | 100% |

A score says pages are well formed. It does not say an assistant cites the site.

## Over HTTP

```
curl "https://mttr.si/api/v1/sites/example.com/compare?with=rival.example" \
  -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 has not claimed the site | 404 | Claim it with `mttr_claim`, then `mttr_claim_check`. |

## 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_compare in the API reference](https://mttr.si/docs/reference#mttr_compare).

## Goes with

- [Competitors](https://mttr.si/docs/tools/competitors.md)
- [A site against its market](https://mttr.si/docs/tools/market.md)