Reproduce problems, gather evidence and verify causes and fixes systematically.
Debugging discipline that cures 'try a tweak'. First, fix the symptom in place: the exact error, its trigger, the shortest path that reproduces it reliably. Second, instead of patching next to the symptom, walk up the chain asking 'who called this?' until you reach the original trigger — padding beside the symptom only guarantees a repeat. Third, hold exactly one current hypothesis and design the smallest experiment that could falsify it. Fourth, before fixing, create a test that fails — it nails the symptom and proves the patch killed the real bug. Afterwards, set guards at the entry point, in the business rules and with environment checks, so the whole class of problem stops recurring silently.
The references cover three routinely ignored skills: when to leave breadcrumbs along the trace, how to find which test pollutes shared state, and waiting on conditions instead of the clock.
Reading code uses the task's tools; tests run with the project's own commands in its authorized environment. The quick patch is not the deliverable — the root cause and its regression test are.
Examples describe the request and the shape of the expected deliverable; they are not completed run results.
This callback intermittently sees an empty directory: don't bolt on a guard — trace from symptom back to the original trigger, with evidence at every hop.
A hop-by-hop trace and trigger verdict; the fix proposal carries its regression test.
The suite passes all together but case two fails alone: find the test mutating shared state and propose the minimal isolation fix.
Evidence naming the culprit case, plus a minimal isolation change.
iOS · Android
iOS
Android
MIT
MIT (root LICENSE)
The pinned skill subtree and shipped references were audited; full applicable license and per-file adaptation/asset notes are preserved under references/licenses/ and references/PROVENANCE.md.
Publication commit 25e07dbeeb, audited source 84c524b6fb; catalog digest iOS 46196ba57ed7… · Android 16de89d019e2….
Version records ship with the signed catalog; the target and released versions are shown below.
