I built this because I use Claude Code, Cursor, and Codex — and got tired of maintaining the same rules in three different formats (.md, .mdc, AGENTS.md).

  ai-nexus lets you write rules once and deploy to all three tools. The key feature is a semantic router that runs on each      
  prompt via a Claude Code hook — it picks only 2-3 relevant rules out of 30+ installed, so you're not wasting context on       
  irrelevant rules.

  AI routing costs ~$0.50/month (GPT-4o-mini or Claude Haiku). Also works with free keyword matching.

  npx ai-nexus install to try it.