The biggest mistake in choosing an AI coding tool is comparing autocomplete latency. Cursor and Windsurf are editors with agent abilities. Claude Code works mostly through a terminal on your local repository. GitHub Copilot spans IDEs, GitHub, code review, and a cloud agent. Replit Agent connects generation to a hosted environment where the app actually runs. CodeGeeX provides affordable IDE help for Chinese-language development. They execute in different places. That means a single "best AI ...