Head hygiene is cheap, deterministic, and the first thing every crawler reads. Reference: references/schema-tier1.md for the structured-data layer that sits alongside the head (owned by M5).
Inputs
Work from the PageSnapshot named in your dispatch envelope: read parsed from <run_dir>/pages/<slug>.json (title, metas[], robots_meta[], canonicals[], word_count) plus headers (content-language, x-robots-tag); Grep pages/<slug>.html for verbatim evidence; site artifacts live in <run_dir>/site/{robots.json,sitemaps.json,discovery.json}. Deterministic findings already emitted by audit.mjs are listed in <run_dir>/findings.deterministic.json — do not re-emit those ids; add model-judged findings only. If invoked directly with a URL/path and no snapshot exists, first run node "${CLAUDE_PLUGIN_ROOT}/scripts/snapshot.mjs" <target> --out "${CLAUDE_PLUGIN_DATA}/runs" and use the printed snapshot path.
Audits
Working from the PageSnapshot (parsed_rendered when render.used is not none, else parsed):
- Title — exactly one
<title>. Length is judged against the shared bands inscripts/lib/bands.mjs(the single source;parse-html.mjs, the on-page checks and this skill all read it): pass 30-60 characters, recommended 50-60. Inside 50-60 the verdict isrecommended; inside 30-60 but outside that,pass; below 30short, above 60long— both arewarn, neverfail. Fail only when the title is missing or empty, or duplicated site-wide across distinct URLs. Not all caps; not a pure keyword list. - Meta description — present, judged against the same shared bands: pass 70-160 characters, recommended 150-160. Outside the pass band is
warn, neverfail— Google rewrites descriptions freely. Not duplicated site-wide; describes this page, not boilerplate. - Viewport —
<meta name="viewport" content="width=device-width, initial-scale=1">present (fail if missing — mobile rendering/indexing depends on it). - Charset —
<meta charset="utf-8">present and in the first 1024 bytes of<head>. - Language —
<html lang="…">present and a valid BCP-47 tag. - Robots meta — sanity-check
<meta name="robots">: flag an accidentalnoindex/nofollowon a page meant to rank. Full indexability/canonical logic (including the canonical tag) is owned by seo-indexability (M2) — here only note presence of<link rel="canonical">, do not adjudicate it.
Fixes
- AUTO — add missing
viewport,charset(utf-8), and<html lang>(inferred fromContent-Languageheader or page text; leave a TODO if ambiguous). These are deterministic, additive, verifiable writes → diff forfix. - PROPOSED — generate/trim a
<title>andmeta descriptionfrom<h1>, lead paragraph, and primary topic: length-bounded, keyword-aware but not stuffed, brand suffix only if the site uses one. Each is a draft requiring per-item accept (humans own messaging). - ADVISORY — removing an intentional
noindexis never auto-written; surface it and let the user decide. - Never fabricate a title, description, or
lang— when content is too thin to derive a value, leave a clearly-markedTODO:placeholder for the user to fill.
Verification
- Method
dom_assert:node "${CLAUDE_PLUGIN_ROOT}/scripts/parse-html.mjs" --snapshot <pages/<slug>.json>(or--url <u>/--file <path>) — returnstitle(value/length/ok),meta_description(value/length/ok),robots_meta,canonical, andhead_hygiene(viewport/charset/lang) so each head element's presence and length is asserted directly against the snapshot. - Duplicate-title/description checks need the full crawl set; when only a single page is available the cross-URL assertion is reported
needs_api, never a falsepass.
Findings
Findings conform to schema/finding.schema.json. Severity policy: 5 is reserved for catastrophic, eligibility-killing facts at site/template scope; 4 major · 3 moderate · 2 minor · 1 cosmetic · 0 informational — and only an established severity-5 fail in an active category can cap a score (references/scoring-model.md). Head hygiene never reaches 5. Examples:
M7.title.missing— no<title>(fail, severity 3,fixable: proposed, axissearch, confidenceestablished).M7.title.length_out_of_band— title 78 chars, outside the 30-60 pass band and likely truncated in the SERP (warn, severity 3,fixable: proposed, axissearch, confidencedirectional). Quote the length and the band that produced the verdict.M7.description.length_out_of_band— description outside the 70-160 pass band (warn, severity 2,fixable: proposed, axissearch, confidencedirectional).M7.viewport.missing— no responsive viewport (fail, severity 3,fixable: auto, axissearch, confidenceestablished).M7.title.duplicate_across_urls— the same<title>is served from several sampled URLs (warn, severity 3,fixable: proposed, axissearch, confidencedirectional). One finding per duplicate cluster, quoting the shared title and the URLs.M7.description.duplicate_across_urls— the same meta description is served from several sampled URLs (warn, severity 2,fixable: proposed, axissearch, confidencedirectional). Both duplicate checks are cross-URL: with fewer than two content pages in the run they are reported once asM7.title.duplicate_across_urlswith statusneeds_api(severity 0, unscored), never as a pass. Platform-conditional ids. This module also emits 6 ids that fire only whenprofile.jsonnames the platform (shopify,wordpress,nextjs,gatsby,jekyll,react-router). They are indexed inreferences/routing.md§ Platform-conditional finding ids and specified inreferences/platforms/<id>.md§10.
Each finding: evidence.observed quotes the head verbatim (e.g. the exact title string + its length); verification.reproduce is the runnable parse-html.mjs command above; expected_impact is banded + confidence-tagged (no naked %).
Honesty
- The "meta keywords" tag is dead — Google ignores it; do not add or recommend it.
- Title/description length bands are SERP-display heuristics (Google truncates on pixel width, not characters), not ranking factors — out-of-band values are
warn, neverfail, and impact isdirectionalat most. The pass band is deliberately wider than the recommended band so a 35-character title is not reported as a defect; both bands come fromscripts/lib/bands.mjsso the script, the report, and this skill can never disagree. - Google frequently rewrites the displayed title/description from on-page content; a perfect tag is not guaranteed to appear, so never promise a SERP snippet as a ranking gain.