Field notes · No. 005
Senior DevOps Engineer building in public. Shipped features across Local Fitness, Ghostwriter, and more — the tradeoffs behind them, and what broke.
An agent skill spent a minute of every run hand-transcribing API responses into its own JSON, and that transcription was the main way data got mangled. The fix is a contract: raw tool output hits disk verbatim, and one deterministic ingest step does all the reshaping.
A generator that proposes additions to a user-owned rule set has to subtract what those rules already claim, and the dangerous overlap is not the duplicate. Building the claimed-set filter, and reporting what it excludes.
An authorisation check that keys on the object alone answers a question nobody asked. Same item, same approved plan, and the verb decides whether the outcome is filing or destruction.
A guard on an irreversible bulk action should over-match on purpose, because a false positive and a false negative are not two versions of the same mistake.
