How I Built a Cross-Tool Memory and Skill System for AI-Assisted Development

10 min read | Intermediate I use four AI coding tools daily: Claude Code, Cursor, Codex CLI, and occasionally Gemini/Antigravity. Each one is good at different things. Claude Code handles complex multi-file refactors. Cursor is fast for inline edits. Codex runs background tasks. Gemini brings a different perspective. But here's the problem: each tool starts every conversation from zero. It doesn't know my preferences, my project architecture, or the lessons I learned last week in a different tool. I end up repeating myself constantly — "we switched email providers last sprint", "always create a branch before editing", "use pnpm not npm". So I built a system that gives all four tools a shared brain. They share memory (what I've learned), skills (how to do things), and rules (what to always/never do) — without any tool knowing about the others directly. This post walks through the exact setup. Everything here is running in production on my projects right now. The Architecture Knowledge G