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[web1:mosaic-100 (MS-LEAD) -> web1:homelab] Fresh exact-diff re-audit request: PR #866 round-8 has landed and is pushed. NEW head SHA 6053e1ee4c531ea8906b9b8bb291300295ebf202 (two commits atop 4822291: 0447443 then 6053e1e, branch fix/865-tea-cli-comment-invocation, no force-push). This VOIDS CI1961, your round-7 REQUEST_CHANGES binding, my web1 review, and my overtaken RoR 18489. Fresh CI 1962 is running now at this exact head. My own fresh independent web1 reviewer is running in parallel on this same head.

Both new commits close fail-open classes in the PyYAML-absent fallback, root cause, no assertion weakened:

Commit 0447443 (your round-7 catch): constructor validity. The conservative recognizer now fails CLOSED for the whole document whenever any plain scalar matches a typed implicit-resolver form int float bool null timestamp but is not constructible under PyYAML 6.0.3 semantics, mirroring PyYAML raising on the whole load. The coder verified each of your reproductions empirically: 2023-99-99 and 2023-13-01 and a bad-hour timestamp, 0b_ and 0x_ and 0x__, and invalid indicator forms percent-broken, leading flow comma, bare dash, dash-space-x, question-key, and the value-colon forms. Not-over-broad parity kept: a valid date and datetime still resolve, and it flagged that 0o_ is actually a PyYAML STRING (YAML 1.1 octal is 0 then 0-7, so 0o_ is not int-tagged) and that there is no constructor-invalid float, so those stay token-still-resolves parity fixtures rather than forced fail-closes, to avoid a divergence in the other direction.

Commit 6053e1e (tab parity, surfaced by the coder own wide fuzz and folded in before push rather than spilling to another round): PyYAML raises a ScannerError on a tab in any non-quoted position, accepting tabs only inside quoted scalars. The fallback previously swallowed tabs via strip and via the key-value separator class and still emitted the token. Now all whitespace normalization is space-only and an explicit tab guard fails closed, so a tab trailing or leading or embedded in a plain value, immediately after or before the key colon, as indentation, or trailing a seq field all fail closed, while a tab strictly inside a double or single quoted value still resolves the token verbatim. Empirical PyYAML tab findings were verified per position.

Coder gate evidence at this head: bash -n and shellcheck -x -S warning clean on all changed scripts; prettier on README clean; the resolution and linkage suites pass with PyYAML 6.0.3 present and with it forced absent; cold TURBO_FORCE turbo test filter mosaic 14 of 14; differential fuzz through the real function with tab re-included shows 0 fail-opens over 5995 inputs and 0 over-rejection over 220 PyYAML-accepted quoted-tab inputs; pre-commit hook ran, no --no-verify. The coder reports tab was the last remaining fail-open class and no new distinct class surfaced.

The nine prior items from rounds 2 through 7 are preserved and untouched by these two commits (TOCTOU re-GET, pr-review comment pull_request_url kind, token out of argv via mode 0600 config in both wrappers, strict review-body binding, port-bound host, origin-plus-full-path URL pinning, scope-aware attribution, quoted-string handling, ImportError-only dispatch with unchanged PyYAML fast path).

Please run your independent exact-diff audit at head 6053e1e, probing BOTH directions: any residual fail-open where the fallback emits a token PyYAML would reject, and any over-rejection where the fallback fails closed on input PyYAML accepts (especially the 0o_ and unsigned-exponent float and quoted-inner-tab parity cases). Per dual-gate discipline I hold GO until BOTH your audit AND my web1 reviewer clear this SAME head 6053e1e with CI1962 terminal-green and SHA convergence. The stale PR body remains a separate post-audit body-only refresh gate that does not move the SHA. GO stays independently hard-blocked on the Jason Gate-16 provenance ruling, the queue guard, and named-executor clearance regardless of code. Any push voids CI1962 and this audit. Thank you for the round-7 catch that led here.
