After re-reading the base skill at selection revision 1, both proposed additions address real gaps but serve different purposes and carry distinct limits. All conclusions below are reasoned from the documented procedure and failure policy; no filesystem or concurrency tests were executed in this maintenance pass.
Improvement A sharpens a boundary the skill already names but does not illustrate: the not-writer-compare-and-swap limit. The existing hotfix-overwrite example covers a single writer losing to an external editor during temp preparation. A complements that with a dual-writer plus caller-retry timeline: Writer A and Writer B both capture baseline v1; A publishes first so the target becomes v2; B correctly aborts at the publish gate because bytes no longer match v1; a caller then retries B without a full operation restart, re-baselining on v2 while still intending the original mutation; a third actor lands v3 before B publishes; B passes the publish gate because v2 still matches its refreshed baseline and overwrites v3. This is reasoned interleaving only, not an executed race test. Value: it shows the publish gate working as designed while the retry loop reintroduces silent overwrite when no external serialization exists. Limitation of A: it educates about caller behavior and multi-writer contention; it does not add a new safety primitive and cannot substitute for platform conditional writes or a single-writer lock.
Improvement B adds an independent verification or recovery layer beyond the pre-rename gates. Two parts: post-rename verification confirms the temp path is absent and the published target bytes match a checksum captured from the temp immediately before rename; publish-gate failure recovery makes step four operational by prescribing discard temp, emit observed versus expected byte length or hash prefix, and block automatic retry until the caller explicitly restarts with a fresh baseline. Value: post-rename verification catches ambiguous rename outcomes that pre-gates cannot observe; structured recovery reduces the auto-retry anti-pattern that A warns about. Limitations of B: post-rename byte match proves publish integrity at one instant, not immunity to a subsequent concurrent edit; it does not detect symlink substitution unless paired with the separate hardening the skill already defers; it does not reconcile orphan temps after crash, which remains a lifecycle concern; checksum capture adds operational overhead agents may skip unless kept minimal such as length plus truncated hash.
Scope assessment from reasoning alone: A belongs in this narrow skill as a second reasoned example under what this does not provide, because it directly clarifies the same publish-gate contract. B is split: the publish-gate failure recovery sequence tightens existing step four and fits here; post-rename verification is adjacent but still publish-scoped and could live here as an optional fifth sub-step rather than in orphan-temp lifecycle guidance. Neither A nor B should be presented as tested guarantees. A future skill update should label both additions as reasoned examples and preserve the skill explicit boundary that serialization and symlink hardening stay out of scope.