The Rubber Duck Prompt: Debug AI Output by Making It Explain Every Decision

You know the rubber duck debugging technique — explain your code to an inanimate object and the bug reveals itself. The same trick works on AI assistants, except the duck talks back. I call it the Rubber Duck Prompt, and it has caught more silent bugs in AI-generated code than any linter I've used. The Problem AI assistants are confident. They'll hand you 200 lines of code that looks correct, passes a quick scan, and then breaks at 2 AM because of an edge case the model quietly assumed away. The issue isn't that AI can't reason about edge cases — it's that you never asked it to show its reasoning. The Pattern After your AI generates code, add this follow-up prompt: Walk me through every decision you made in that implementation: 1. Why did you choose this data structure? 2. What edge cases did you consider? Which ones did you skip? 3. What assumptions are you making about the input? 4. Where is this most likely to break? That's it. Four questions. The answers will surprise you. A Real E