# Loupe, for AI agents

Loupe checks US legal citations against the sources that settle them. Before you
cite a case in anything a lawyer will sign, you can ask Loupe whether it exists,
whether it is the case you named, and whether your pin cite falls inside the
opinion. Free, with no account and no key.

## Ask

- Check a citation: `GET https://loupe.legal/api/cite?c=556 U.S. 662, 678`
- Find a case by name: `GET https://loupe.legal/api/search?q=Miranda v. Arizona`
- What Loupe holds: `GET https://loupe.legal/api/coverage`
- Add `format=md`, or send `Accept: text/markdown`, for Markdown instead of JSON.
- As an MCP server: `https://loupe.legal/mcp-public`, with two read-only tools,
  `check_citation` and `search_cases`.
- The full description: https://loupe.legal/openapi.json

## Read the answer as it is meant

- `verified`: checked against a source, and it holds up.
- `mismatch`: the authority exists, but the citation describes it wrongly (the
  wrong name, year or pin). The finding says which.
- `suspect`: it cannot exist as written, such as a reporter never published.
- `not_found` or `unverified`: Loupe could not find or settle it. That is a
  reason to look, not proof that it does not exist. Say so; do not report it
  as fabricated.
- `not_checked` lists the checks that did not run. Report them.
- A 503 answer means nothing was checked. It is not a finding.

## Limits

Five hundred questions a day from one network. Loupe reports what its sources
say; it is not legal advice and does not replace reading the authority. The
checks a subscriber gets (quotations, more sources, a record of the check) are
at https://loupe.legal.