Make No Mistakes

The whole prompt. Nothing else.

Make a modern to-do app. Single HTML file. Make no mistakes.

Raw API, no system prompt, one shot. Every build is live: play it, or put two side by side.

The numbers

Click a column to sort. Cost is what OpenRouter billed for that one call. Time is wall clock from request to last token.

How it was made

One request per build

Each build is a single call through OpenRouter with one user message: the prompt above. No system prompt, no temperature, no examples, no retries for quality. If the call failed before any output, it was retried (counted on the card); a bad build stays bad.

The only knob that changes is reasoning. Same model, different effort: you can see what thinking harder buys.

The request body


    

    

      
Honest footnotes

      
    
        
  • Reasoning off exists only where the model allows it: Haiku 5.5 and GPT-6.1 Terra. Opus 5.5 and GPT-6.1 Sol refuse to switch it off, and Sonnet 5.5's off switch isn't exposed through OpenRouter, so those three start at low.
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  • Code is cut out of the response as-is. Every build page gets one tiny script that gives it its own storage, so two to-do apps don't read each other's lists. The untouched response is linked on every build.
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  • Thumbnails are a screenshot 2.5 seconds after load, before anyone touched anything.
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