Two failure classes the repository paid for are not covered by the isolation,
synchronization, and teardown rules already in the skill.
A value the operating system owns is not guaranteed to return as written. A
test may write one back only where the assertion tolerates that write-back
failing; where the assertion depends on it, the expected value comes from a
fresh read. NTFS truncating a fractional-millisecond mtime and Windows folding
environment variable name case are the two instances seen so far.
A describe or case timeout overrides the runner's --testTimeout rather than
yielding to it, so a value below the lane budget lowers what CI granted, while
the same literal reads as a widening where the host default is smaller. The
hook budget travels with the test budget, and a case asserting a timeout keeps
its outer wait far larger than the timeout under test. Restoring a granted
budget, or sizing a bounded retry to measured contention, is named as distinct
from the masking fixes the skill rejects.
The diagnosis reference gains the platform differences under its platform
class, a classification path for self-hosted pools that expose no host metrics,
and the stopping rule for a signature no available host can reproduce.
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