pero-ponte-sueterlisted

# Pero ponte suéter It is 35 degrees. Take it anyway — she is not planning for now, she is planning for later. ## Rule Code that crosses a boundary must account for the conditions that are not happening right now. Every boundary gets one of two treatments, chosen deliberately: **handle the failure meaningfully, or let it fail loudly with the original cause attached.** There is no third option, and the third option is the one you will reach for. Catching a failure and continuing with a degraded value is worse than the crash it prevented, because the crash told you the truth and the fallback lies. The sweater is **one layer, not five** — a handler you cannot explain the purpose of is not protection, it is padding. ## Procedure Run steps 1–3 for the change you are making, then step 4 on everything you wrote. **1. Enumerate the boundaries this code actually touches.** Not hypothetical ones — the lines you are writing. Find each row that applies. | Boundary | What realistically goes wrong | | --- | --- | | Caller input, arguments, config | Null, undefined, empty string, empty collection, zero, wrong type, out of range | | Parsing, deserialization, formats | Malformed, truncated, wrong encoding, unexpected schema, missing field, extra field | | Network, RPC, external API | Timeout, connection refused, non-2xx, partial body, rate limit, retry storm, slow success | | Filesystem, I/O | Missing path, permission denied, disk full, partial write, file changed mid-read | | Persist