Most Cursor rules I see online are wish lists. "Write clean code." "Follow best practices." "Be concise." Cursor reads them, nods politely, and ships exactly the same code it would have without them.
The reason is simple: vague rules give the model nothing to act on. A rule only changes output if it's specific, enforceable, and scoped to when it matters. After rewriting my rules around those three properties, Cursor went from "code that works but I'd reject in review" to "code that passes review the first time" on most requests.
Here's what actually moved the needle, with real .mdc rules you can paste in.
The format: .cursor/rules/*.mdc, not .cursorrules
Cursor has moved to Project Rules stored as .mdc files in .cursor/rules/. The big advantage over the old single .cursorrules file is scoping: each rule has frontmatter that controls when it loads.
