Individual skill

constraint

Use this skill whenever the design must structurally prevent invalid actions — input validation, disabled states, required fields, type-restricted inputs, mode locks, role-based gates, hardware lockouts. Trigger when designing forms, picking input types, designing destructive flows, gating multi-step procedures, or thinking about how to prevent a class of errors from being possible at all. Constraint is one of the foundational principles in 'Universal Principles of Design' (Lidwell, Holden, Butler 2003) and one of the strongest design moves available — preventing wrong actions is more powerful than detecting them after the fact.

plugins/interaction-and-control-principles/skills/constraint/SKILL.md

Source commit 09b9858fc983fe917b7fedae67a9625d9e6655a6

What was checked

Matches the observed repository HEAD

Yes

Scanner rules are current

Yes

Repository scan complete

No

Skill scan complete

Yes

Observed behavior

Instructions only

Last checked

Nov 6, 2026

These are observations at the recorded commit, not a guarantee of safety. Review the source before running it.

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