Quiz Entry - updated: 2026.07.14
What are the modal verbs used in requirements templates and what do they indicate?
They signal how binding a requirement is: MUST/SHALL (mandatory) → SHOULD (recommended) → WILL (statement of intent) → MAY/CAN (optional).
| Modal Verb | German | Meaning |
|---|---|---|
| MUST/SHALL | MUSS | Mandatory requirement - legally binding |
| SHOULD | SOLL | Strongly recommended - expected unless good reason not to |
| WILL | WIRD | Statement of fact or future intent |
| MAY/CAN | KANN | Optional - nice to have |
Template structure:
[WHEN condition] THE SYSTEM <system name> MUST/SHOULD/WILL/MAY <process verb> [WITH <details>] <object> [<additional details>]
Example: "When the user clicks submit, THE SYSTEM SHALL validate all form fields WITH appropriate error messages."
Go deeper:
RFC 2119 — Key words for requirement levels — the internet-standard definitions of MUST/SHALL, SHOULD, and MAY that this modal-verb hierarchy mirrors.