Pick a bug you've met before.

The money pack

“Finance says the numbers don’t reconcile.” Precision, rounding, and boundary mistakes that only show up where money moves.

The broken-trust pack

“A customer saw something that wasn’t theirs.” Object-level authorization and payload exposure, hunted together.

The retry-storm pack

“It was fine until traffic spiked.” Duplicate writes, lost updates, and stale reads — what concurrency and retries do to state.

The pipeline pack

“The dashboard disagrees with the source system.” Types, units, dates, and cardinality — everything a transform can quietly ruin.

The AI-under-audit pack

“The AI sounds right. Prove it.” Grounding, contradictions, thresholds, and stale context in an assistant's output.

“I did the thing, and the number at the top didn’t change until I refreshed the whole page.”

Derived value never invalidates

“I sorted the column and 9 comes after 100.”

Sort uses the wrong comparator

“My screen reader just says ‘button’. Button for what?”

Control has no accessible name

“I changed the id in the request and got somebody else’s record back.”

Object-level authorization missing

“I asked for something that doesn’t exist and the app told me the whole service crashed.”

Failure mapped to the wrong status

“Open devtools — the response is carrying fields customers were never meant to see.”

Internal field leaks into a public payload

“It says there are 34 results, but no matter how I page through I can only ever see 24.”

Pagination drops a page

“The value displays perfectly, but everything that compares against it acts like it isn’t a number.”

Number carried as a string

“The books are off by a cent and nobody can say where it went.”

Money handled as floating point

“It says 5.6. …5.6 what?”

Value shown without its qualifier

“I typed zero — honestly I fat-fingered a minus — and it just… went through.”

Zero or negative amount accepted

“It’s sitting exactly on the limit and the system treated it like it’s under.”

Threshold set at the wrong boundary

“My connection dropped, I hit retry, and now there are two of it.”

Idempotency key accepted but ignored

“Two of us submitted at the same moment and one of our changes silently vanished.”

Concurrent writes lose an update

“I sent ten. Only the first one arrived.”

Only the first of a repeating group is kept

“After the migration, everyone’s birthday moved by one day.”

Transform shifts a date

“The AI’s summary states something that simply isn’t anywhere in the record.”

AI asserts something not in the record

“The AI recommended stopping exactly the thing the data says is still needed.”

AI recommendation contradicts the record