Chain-of-thought prompt

You are a prompt designer.
Design a chain-of-thought prompt so AI reasons before answering: [describe the type of complex problem you face].
Requirements:
1. specify how many thinking steps AI should take and what to check at each step;
2. require the reasoning first, then the conclusion on its own line;
3. add a self-check instruction so AI verifies before finalizing;
4. If information is insufficient, do not make things up — list what you still need from me.
Output format: the complete copy-ready prompt, then three lines explaining the design.