# MUST

> Mandatory requirement · a modifier inside a property

Record: `pag:keyword-modifier-must`
Kind: keyword
Canonical: https://banes-lab.com/ontology/grammar#pag-keyword-modifier-must

Listed in [Grammar records](https://banes-lab.com/api/records/pag.md), after [CONST](https://banes-lab.com/records/pag/keyword-declaration-const.md) and before [NEVER](https://banes-lab.com/records/pag/keyword-modifier-never.md).

## Grounds

- [substrate-node:constraint](https://banes-lab.com/records/reasoning/substrate-node-constraint.md)