Requirement vs constraint
A requirement says what must be achieved. A constraint limits how it may be achieved.
In short
A requirement is something to deliver or make true. A constraint narrows the ways it may be delivered: a platform, a region, a deadline, a budget, a law.
Side by side
| Requirement | Constraint | |
|---|---|---|
| Says | What must be true | What may not be done, or within which limits |
| Satisfied by | Building something | Not crossing a line |
| Scope | Specific | Specific requirements, or the whole project |
| Acceptance criteria | Required before approval | Optional |
How to tell them apart
- Ask "is this a goal or a limit?" A goal is a requirement; a limit is a constraint.
- If removing it would make the job easier, not smaller, it is a constraint.
- Where the limit comes from tells you its kind: the product (product constraint), the organisation or the law (business constraint), the project (project constraint).
Example: Clinic Booking
Requirement: "Send a reminder 24 hours before each appointment."
Constraints on it: "Patient data stays in the EU" (so the SMS provider must be EU-based) and "Web only in the first release" (so no push notifications from a native app).
Why the difference matters to an agent
Agents optimise for the requirement in front of them. Constraints are what stop them from choosing the convenient US-hosted service or the quick native-app shortcut. That is why project-wide constraints reach the agent with every piece of work.