Sanity Check

What I Asked For

The concept was simple: a web app where you type in an idea and an AI tells you whether it’s a good one. Not a paragraph of hedged advice, not a list of 12 considerations. A verdict. Good or bad. A score. A reason. Any major concerns worth knowing about.

The structure of the output mattered as much as the output itself. The AI needed to return something specific and consistent: a verdict label (good idea or bad idea), a numerical score from 1 to 10, two or three sentences of reasoning, and a callout for any real concerns. No rambling. No qualifiers. Just the call.

The design direction was dark and intentional. Space-gradient background, glass morphism card, the kind of UI that feels like it’s doing something serious even when it’s evaluating whether your idea for a guitar pedal subscription box has legs.

What It Is

Sanity Check is a React app that calls the Claude API directly from the client. You type your idea, hit the button or press Ctrl+Enter, and the app sends it to Claude with a tightly constrained prompt that forces a JSON response in a fixed shape: verdict, score, reasoning, concerns. That structure is what makes the result feel like a verdict rather than a conversation.

The result screen shows a green checkmark for good ideas, a red X for bad ones, the score as a badge, and the reasoning and concerns in separate sections. There’s a reset button to run another idea through immediately.

It is deployed at sanity-check-gilt.vercel.app. The whole thing started as a five-minute concept and became a working app in a single session. That’s sort of the point.