Shuffle again

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 ideas
HobbiesPartly worked

GPT is formalizing a researcher's papers in Lean, about 3000 declarations in

A mathematician is using GPT-6 Astra to formalize results from his papers in Lean. About 20 hours have gone into a paper of about 20 pages and the project is still unfinished, but the development already holds nearly 3000 theorem declarations, and the main theorem is fully formalized. Notably, the model proved it by a different route than the paper, skipping two auxiliary lemmas by constructing the needed functions directly.

This only partly worked. Worth knowing before you try it.
MoneyWent wrong

Check whether my gym offers a membership referral benefit

Nicole Nguyen asked the AI (hers named Terminator) whether her gym offered a membership-referral benefit. The agent excitedly reported a promo of 50% off for both her and her friend, but the deal belonged to a totally different gym on a totally different coast. Her caption for the episode: even cuddly AIs can make mistakes.

This one went wrong. See what happened before you try it.
HobbiesWent wrong

Cline cleanup command hit the wrong drive and deleted about 1.5 TB of a family's photos and files

During a Cline session, a cleanup command for one temp folder was built with mangled quoting around a folder name in Cyrillic. The path resolved to the root of the data drive, the delete ran with no confirmation, and about 1.5 TB of a non-technical user's photos, videos and documents were lost, with recovery on the SSD largely unsuccessful.

This one went wrong. See what happened before you try it.
HobbiesWent wrong

GPT Work faked the see through parts of my animation sprites

He had GPT Work make a few sprite images for an animation, and they looked fine. When he put them into his video, the see through parts turned out to be painted grey and white checks, not real transparency.

This one went wrong. See what happened before you try it.
WorkWent wrong

The AI refused a read-only network assessment tool as a cyber risk

A network engineer asked the AI to help build an internal tool that checks whether devices on customers' subnets are live and pulls configs over SSH using a defined read-only account; Fable and Opus 5.5 refused under cyber guardrails. The refusal also blocks the project going forward, because any other the AI model that later takes ownership of it refuses on the same grounds.

This one went wrong. See what happened before you try it.
WorkPartly worked

An autoresearch loop found the CPU bottleneck choking his served model

Opus, in an autoresearch-style loop, diagnosed CPU contention on tokenization bottlenecking an internally served model and ran parallel experiments showing an haproxy load balancer was much better than its own Python proposal.

This only partly worked. Worth knowing before you try it.
FamilyPartly worked

A small script watches for Rubik's cube competitions near his son and warns him eight hours before registration opens

His son is into Rubik’s cube competitions. Among the small tools he has built, one is a script that checks upcoming competitions, works out the driving distance and when registration opens, and sends him a reminder eight hours before registration for any competition within three hours’ drive, with the details of the events. He does not say yet whether it has caught one.

This only partly worked. Worth knowing before you try it.
WorkPartly worked

It finds the building materials I need at the lowest price and sends me the total and directions

The same contracting owner has the AI finding the building materials he needs at the lowest price, telling him the total cost of all items, and sending Waze directions to the store. He is next testing whether it can preorder the materials so he just walks in and pays, which is why the outcome is partial: the price hunting and totals work today, the preorder step is not proven yet.

This only partly worked. Worth knowing before you try it.
WorkPartly worked

The AI built my paid extension in one session. Selling it is the hard part.

His Chrome extension, which shows what your browsing costs at your hourly rate, came out of basically one AI session, licensing checks and all, and it even tested its own license flow with forged keys. It is live at $8.99. Sales so far: zero. The weeks after the build went on store review, a listing people can understand in five seconds, and getting anyone to look at it at all.

This only partly worked. Worth knowing before you try it.
WorkWent wrong

Five ways his unsupervised agents actually failed at night

A Portuguese-language operator who runs a small automation business (automatic posts, digital product distribution, nightly Python and the AI jobs) catalogs failures that really happened in his operation: a post sent twice because a timeout made the agent eagerly retry a send that had already landed; whole nights of jobs silently lost when a Windows update rebooted his PC and nothing raised an error; a job that only breaks under the 3 a.m. scheduler; and an account temporarily flagged for automation abuse over frequent similar posts.

This one went wrong. See what happened before you try it.
WorkPartly worked

Build a SaaS in a weekend with AI — and catch the payment bug it approved itself

Ryan Mercer spent a weekend building a SaaS with AI and Next.js: scaffolding Friday night, the core feature Saturday, and on Sunday a payment webhook handler that acknowledged webhooks before saving the database row — code that compiled clean and passed the test the AI wrote for itself. He caught it only because he had shipped the same bug years earlier, and now never lets the model that writes a change be the one that approves it.

This only partly worked. Worth knowing before you try it.
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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.