Every AI coding tool faces the same fundamental problem: your codebase is too large to fit in a context window, but the model needs to understand it to help you. How a tool solves that problem shapes everything about what it can and can't do. GitHub Copilot and Claude Code solve it in opposite ways — and the gap between them isn't a matter of polish or features. It's a genuine architectural disagreement. How Copilot Works: Index First, Retrieve Later If your repository is hos