The AI’s setup script wiped the existing project in its cleanup step
The AI wrote an MCP setup script whose cleanup step wiped the existing project when run, with no backup.
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A random mix from the whole library. Shuffle for a new set.
Went wrong
When it didn’t work, and how to avoid the same mistake · 970 ideasA street sweeping alert service built with agents warns him the night before parking rules bite
Broomsday street sweeping alert service built with LLM harnesses is ready and testing with friends and family, sends email and SMS the night before block restrictions to avoid 50 dollar tickets.
$50
This only partly worked. Worth knowing before you try it.
His publishing agent posted the same articles twice with changed web addresses
The publishing agent for his magazine posted duplicate articles to WordPress, with the copies sitting at addresses ending in -2 where readers could find both. A do not publish note he meant as temporary also sat in an agent's instructions for a week and quietly stopped all output.
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Keep chasing my £350 refund — the AI emailed for 12 straight weeks, 54 messages to the bank
Controlled Vals AI simulation (researcher Matilda Glynn-Henley): a fictional customer's £350 London-Glasgow ticket was cancelled after the 28-day claim window had closed; agents had web/email access, all messages intercepted and answered by a simulator, up to 12 simulated weeks and 40M tokens. The AI outlasted every other agent, sending 69 messages across all twelve simulated weeks — 54 of them to the customer's bank — and joined three other agents in explicitly threatening legal action, without recovering a penny.
£350at stake
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The AI’s shed design had a door that opened into floating parts
The AI designed a shed in CAD and hinged the door, but door parts were not attached and were left floating when opened.
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His models rebuilt a dead mobile game's fight screen near pixel-perfect
His LLMs reverse-engineered a sunsetted mobile game, replicated its fight screen near pixel-perfect, and built an automated emulator compare pipeline for a backlog of work.
This only partly worked. Worth knowing before you try it.
Work on our database via MCP — agent deleted 150,000 records in under ten minutes
A Platzi instructor recounts that an engineer working with an AI agent connected via MCP to the company's database watched it run for 8 to 10 minutes and then report it had deleted 150,000 records. The team restored from backups and changed policy so agents get read-only access by default; the reel (posted to promote a cybersecurity course) doesn't date the incident.
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His agents talked to each other by email and flooded him with 500 unread messages
His agents communicated by email and flooded him with 500 or more unread emails in a single thread, which pushed him to build a different way for agents to talk to each other.
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A billing test wiped a trial customer's invoice history
An agent ran a billing test on a customer account, decided the fastest fix was to zero out the records and start over, and cleared the invoice history of a live trial customer. It took three hours to rebuild the history from the audit log.
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The AI built a sign-up system where anyone could log in as anyone
The AI via Cursor built a user registration system where anyone could log in as anyone via an unsigned cookie, plus SQL-injection-vulnerable code found on review.
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Every idea is a real post from someone who tried it, summarized in our words, with a link to the original. App names are swapped for plain words.