The Model Isn't the Bottleneck — Your Prompt Structure Is

The Experiment Chris Laub (@ChrisLaubAI) ran an experiment that should change how you think about model selection. He built the same application five times — once with each major LLM — and tested five different prompt formatting styles across all of them. The top scores by model (best prompt style for each): Model Best Score Best Format Claude 87 XML GPT-4 71 Markdown Grok 68 — Gemini 64 — DeepSeek 52 — Claude with XML prompts dominated. But here's the more interesting finding: Claude scored 89 with Markdown prompts too. The model was strong regardless of format — but every other model showed dramatic swings depending on prompt structure. The Real Takeaway: Structure > Model The gap between Claude's best and DeepSeek's best is 35 points. That's a model gap, and it's real. But look at it from a different angle: for several models, the gap between their best and worst prompt style was comparable. Changing how you structure your prompt can matter as much as changing which model you use