Paste the exact error and ask for three things: what it means in plain English, the smallest change that would fix it, and what it is not. Without that last part you get a rewrite of something that mostly worked.
The prompt
Here is the exact error: [paste it]. Explain in plain English what it means, tell me the smallest change that would fix it, and tell me what this error is NOT caused by. Do not rewrite anything else.
| When to use it | The first time you see an error, before trying anything. Especially if you cannot read code. |
|---|---|
| Why it is worded that way | Handed an error, a builder tends to regenerate a whole component — which often works and leaves you with new code you understand even less. Asking for the smallest change keeps the app one you can still reason about. Asking what it is not stops you from chasing the wrong thing for an hour. |
Paste the error, not your summary of it
'It says something about undefined' removes the part that identifies the problem. The exact text, including the line and the file, is what turns a guess into a diagnosis.
One error at a time
Errors cascade: one real failure produces five messages. Fix the first one and the rest usually disappear. Handing over all five invites five changes, four of which were unnecessary.
When to stop asking and start reverting
If two attempts have not fixed it, go back to your last working version and make the change again in smaller steps. Continuing to patch a broken state is how a ten-minute problem becomes an evening.
The Build Prompt Pack
This is one of 57 prompts, from the phase "When it breaks". The pack has the rest, each with the same reasoning underneath, plus the research they are built on and a house-rules file you paste in once.
Tools this applies to
| Tool | What it does | Price |
|---|---|---|
| Lovable | Builds complete apps from a prompt. The most finished output of the group. | Free tier, then ~$25/mo |
| Bolt | Fast full-stack prototypes, entirely in the browser. | Free tier, Pro ~$25/mo |
| Replit | Building and hosting in one place, agent included. | Free tier, Core ~$20/mo |
| Emergent | AI that builds and iterates on working software rather than snippets. | Free tier, then ~$20/mo |
Every tool has its own page with what it costs and who should skip it. Some links are affiliate links.
More prompts like this
The prompt that stops an AI agent going in circles
What do you do when an AI coding agent keeps trying fixes that do not work?
The prompt to ask before you change anything
How do you change something in an AI-built app without breaking the rest?