What it means
Rules encode non-negotiables: coding standards, design tokens, refusal policies, file paths to avoid, and review requirements loaded automatically at task start.
Why designers should care
Designers should co-author rules with engineering so agents respect accessibility, component usage, and content voice, turning design system intent into machine-enforced defaults.
Example
A .cursor/rules file requires WCAG AA contrast checks and bans raw hex colors; every agent UI task inherits these constraints before generating components.
Common mistakes
- Rules that duplicate skills with conflicting guidance.
- Overlong rule files that consume context window before user content.
- No ownership or changelog when rules change team behavior overnight.
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Frequently asked questions
What is Project Rules?
Project rules are always-on instructions that shape agent behavior for a repo or workspace, often stored as .cursor/rules, AGENTS.md, or team policy files.
Why should designers care about Project Rules?
Designers should co-author rules with engineering so agents respect accessibility, component usage, and content voice, turning design system intent into machine-enforced defaults.
What are common mistakes with Project Rules?
Rules that duplicate skills with conflicting guidance; Overlong rule files that consume context window before user content; No ownership or changelog when rules change team behavior overnight.