System Design: 100 Interview Questions by X.Y. Wang

How can I use system prompts to improve AI coding assistance?

A system prompt sets persistent instructions for every interaction — for example: "You are a TypeScript expert. Always use strict types, never use 'any', prefer functional patterns, and handle errors with Result types." Tools like Cursor allow custom system prompts per project via a .cursorrules file. This is one of the highest-leverage ways to improve AI output consistency across a codebase.