Cursor rules best practices: write rules your agent won't ignore

Cursor Rules (.cursorrules) only work if the agent can follow them. Most teams write a wall of text and wonder why nothing changes.

Be specific and actionable

Replace "write clean code" with "run pnpm lint before marking a task done." Agents follow concrete commands far better than adjectives.

Keep it short

The rules are injected into context on every request. A 200-line file burns tokens and buries the important bits. Aim for the load-bearing conventions only.

One rule, one concern

• Imports: barrel files only, no deep relative paths.
• Tests: co-locate next to source, name *.test.ts.
• Types: prefer inferred; explicit only at module boundaries.

Generate, then trim

Start from a scan-based draft so the rules reflect your actual repo, then cut anything generic. Generate Cursor rules from your repository and keep the 10% that matters.