# OpenPredicate MCP server

> Provides a JSON-encoded, SQL-flavored predicate language for standardized API search filtering and MCP tool input schemas.

- Repository: https://github.com/OpenPredicate/open-predicate
- Page: https://hostedmcp.org/servers/openpredicate/open-predicate
- Transport: —
- Stars: 5
- License: MIT

## FAQ

### How do I install OpenPredicate?

You can install it via npm using the command `npm i @open-predicate/open-predicate` (requires Node >= 20.10).

### What is the difference between $exists and $isNull?

$exists tests if a key is present on the record, whereas $isNull tests if the value of a key is null.

### Does $in search inside arrays?

No, $in compares the value as a whole. To check for element membership in an array, you must use a quantifier like $some.

### How are sibling members in a JSON object treated?

Sibling members are treated as being joined by an AND operator at every level.