seo-meta-onpage (M7)

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 in scripts/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 is recommended; inside 30-60 but outside that, pass; below 30 short, above 60 long — both are warn, never fail. 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, never fail — 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 accidental noindex/nofollow on 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.