Reproducible lab · Synthetic metadata
Test the release boundary, not a fabricated Google result
This checked-in benchmark exercises the real metadata comparison engine against safe, blocking, uncertain, malformed and adversarial inputs. It reports engine behavior and export integrity only.
Worked synthetic benchmarkResults below come from reserved
.test fixtures and the checked-in test command. They are not live Search results, Google measurements, production traffic or independent human certification.Method
- Read exact UTF-8 fixture bytes and tokenize supported head metadata without executing HTML.
- Run complete, blocking and uncertain comparisons through
fasttool-metadata-release-gate/1.2.0. - Preserve browser-first duplicate attributes, use HTML ASCII whitespace, and fail closed on malformed comments, raw-text/head-exit wrappers or parser coverage gaps.
- Reject malformed, NUL-containing and greater-than-64-KiB head input before artifact generation.
- Export active metadata only for PASS; other verdicts receive a non-executable review plan.
- Generate all text artifacts twice and compare exact bytes and SHA-256 hashes.
node scripts/snippet_release_gate_engine_test.mjs
node scripts/build_snippet_benchmark_receipt_20260804.mjsExpected versus observed
| Scenario | Expected | Observed | Evidence |
|---|---|---|---|
| Complete supported change | PASS | PASS | Supported metadata and parser coverage complete |
| Noindex + duplicate canonical | BLOCK | BLOCK | robots_noindex and duplicate_canonical retained |
| Approximate title boundary | INDETERMINATE | INDETERMINATE | Fixed local mobile-width threshold crossed |
| Duplicate content attribute decoy | BLOCK | BLOCK | First HTML attribute remains authoritative; duplicate coverage is disclosed |
| Unclosed comment decoy | Reject | Rejected | No artifact is minted from an unfinished comment scope |
| RCDATA/RAWTEXT and head-exit wrappers | Not PASS | Rejected or BLOCK | Metadata-looking text outside the real head scope is never trusted |
| NBSP parser divergence | Not PASS | BLOCK or INDETERMINATE | Only HTML ASCII whitespace separates tag, attribute and rel tokens |
| Malformed or oversized head | Reject | Rejected | No artifacts produced outside the input boundary |
| BLOCK implementation output | Non-executable | Non-executable | Review comments only; dangerous metadata is not emitted |
What the boundary means
Measured
Parser coverage, explicit metadata policy, verdict precedence, deterministic glyph-class estimates, export escaping and exact artifact bytes.
Not measured
Google title-link or snippet selection, device-specific Search UI, rewrite frequency, index status, rank, CTR, traffic or revenue.
The width model exists to make a release review repeatable. It deliberately produces INDETERMINATE when the local estimate crosses a stated threshold; it never claims that Google will truncate the same text.
Fixture provenance and SHA-256
- pass-baseline-head.txt097334ec9460a83a4e33562064febb1a2272f4f3234874d6c28d2e0cc9f23656
- pass-current-head.txt61a66bd0a59b7a020169ed4e978af455b28754525f7c6b3d636bc67d22de2672
- block-current-head.txt72e11eeabc5d9d853b8e96f494ea2fa41b9b9bd47f0be63ccc079c404915cd4b
- duplicate-attribute-current-head.txt52d677a7a9c3e001b1963c0863bf4591efc375217b3d3e9652e1a5b184fdee5c
- unclosed-comment-current-head.txtb84e2f4c27c265c67da6e4712f574bbf6f95522e2c3d3a87794a804fbf2b6604
- malformed-head.txt890ac1b4c3d59d91368a6942e09d17cac97e2018e2ae858bb761304cf72ff752
- rcdata-decoy-current-head.txt72de2745d477292db2fefd7c19c43dbf27c23b25a6cc53c052b203eca8cd97e4
- parser-adversarial-cases.json21300dff2a9806a71925015e77a7b1b75722233ba81cf0cfcd1fa1eadc967204
Downloadable benchmark evidence
Machine results
Download JSON6416d644d335bf8dfa6a64e016b1bef84533a395d66c3c63b6432b975500949eScenario ledger
Download CSV4e0c7f48d8b5de0b601b037e55a264f31766c52b8e28764c349f825e210b06cbMethodology
Download Markdownb1d93ccdae6ed4ff350a5dc468c845d268ee3d09566bc5ebb0bb78cbbea363ffReceipt v1
Download receipt4cd6d5e612be6d4d4e21c59dd2dd2c5ed61f97842b26d2719285079eb610d833Receipt-core SHA-256
904bb052475b354cb868567e71c1d41ba35f785689b7fa8cd5e9b3f709bc5c62Sources, limits and correction
- Google Search Central: title links
- Google Search Central: snippets
- Canonical consolidation
- Robots meta directives
FastTool is independent from Google. Report a fixture, method, hash or result defect to [email protected]. Include the artifact hash, runtime and observed assertion.