Cursor project rules must be .mdc files, or they're ignored
Rules in .cursor/rules need the .mdc extension plus frontmatter. A plain .md file there is silently skipped; use AGENTS.md for plain markdown.
Cursor tips & tricks
Keep Cursor rules minimal; move occasional workflows to skills
Every rule costs context in every chat. Cursor recommends short, specific rules (<500 lines) and skills for things you need only sometimes.