How I Use Codex, Claude Code, and Cursor Together Without Burning Money

The fastest way to waste money on AI coding tools is to treat all of them like interchangeable magic IDEs. I did that at first, and the result was predictable: vague prompts, duplicated work, too many open sessions, and a bill that grew faster than the product. The fix was simple. I stopped asking every tool to do everything. Codex is my execution engine inside a real repository. I use it when the task is concrete: implement a feature, fix a bug, update tests, review a diff. Claude Code is my heavy researcher.