Common Vibe Coding Mistakes and What Each One Costs

The most common vibe coding mistakes are asking for too much at once, not saving working versions and believing the AI when it says "done". You do not need to learn programming to avoid them, only a few habits.

What do these mistakes look like in a real project?

Here is an invented diary. Priya is making Dusk Moths, a small game where you guide moths to a lamp before dawn.

• Day 1: everything in one message. She asks for moths, twenty levels, a shop, a night cycle and saving. She gets five screens, and none of them quite work. Cost: three days of untangling. Instead: ask for one moth, one lamp and one screen.
• Day 4: art before fun. She spends an evening on moth pictures before she knows whether guiding moths is any fun. Cost: pictures for a game that then changes. Instead: keep grey squares until someone asks for a second round.
• Day 6: no saved versions. One change wrecks the night cycle, and there is no way back. Cost: a whole day, rebuilt from memory. Instead: have your AI save a version each time something works. Undoing AI changes with Git shows how.
• Day 8: believing "done". The AI reports that the shop is finished. The buy button takes the coins and gives nothing back. Cost: her sister finds it a week later, in front of friends. Instead: ask what it actually tried.
• Day 11: a secret key inside the game. She wants funny moth names from an online AI, so she pastes her key into the game. A key is a password for a paid service. Google's guide warns that keys in a web app can be pulled out by users, and says to make those calls from a small server instead. Cost: a stranger could spend her money. Instead: keep keys out of anything players download.
• Day 14: starting over. She opens a new project. Cost: all of the above, again. Instead: read how to finish instead of restarting.

Which mistake should you fix first?

Sort them by how much damage they can do, not by how often they happen:

1. The key. It is the only one here that can cost real money by next week.
2. Saved versions. Once you have them, every other mistake gets cheap.
3. Believing "done". This is what lets broken things pile up unseen.
4. Too much at once, then art too early. These waste evenings, but they break nothing.

If you only have ten minutes today, check for keys and save one version. If your game keeps falling apart after that, go on to my game keeps breaking.

Paste this to your AI

Look through my game project for mistakes, but start with a map.

First draw how the game is meant to flow as a Mermaid diagram: every screen and button, and where each should lead. Follow each arrow through the real game and mark every spot where the two differ. Show me this before anything else.

Then report these five mistakes, worst first:

1. A secret key or password in any file that players could get at.
2. No saved versions, or unsaved work sitting there right now.
3. Things that look finished but lead nowhere. The map will show you these.
4. One feature spread over so many places that a small change would touch all of them.
5. Finished art for parts of the game that may still change.

For each finding, name the file and the place in the game, and quote the line or tell me what you tried. A finding with nothing behind it does not count, so leave it out. For anything you could not look at, write "I could not check this" and tell me what you would need. Do not change anything yet.

Or skip this and connect the MCP: your AI then finds all of this by itself.Connect the MCP

How to check it worked

• Read the map first. It is a plain drawing of your game, so you can judge it without knowing any code. If it reaches you as text, ask your AI how to view it as a picture. Is this the game you meant?
• Follow one finding. Go to the place your AI named. Is it really what the AI says it is?
• Press every button once. Write down any that do nothing, then compare with the AI's list. If you found one it missed, tell it.
• Ask about the key directly. Ask where your key is kept and whether a player could reach it. It should name the place, or say it found no key and where it looked.
• Practise the way back. Make a silly small change, such as a pink moth, then ask for the last saved version.