$npx -y skills add Hainrixz/claude-seo-ai --skill seo-renderingAudit a page's rendering strategy and JavaScript dependency — diff raw HTML against the rendered DOM to measure how much primary content, links, headings, and JSON-LD exist only after JS executes, classify CSR-only / SSR / SSG / ISR, and emit framework-specific guidance. Module M
| 1 | # seo-rendering (M4) |
| 2 | |
| 3 | Most AI crawlers do not execute JavaScript, so content that only exists after hydration is invisible to them — CSR-only is a hard AI gate. JS dependency also delays first paint; see `references/cwv-thresholds.md` for how this feeds LCP/INP. |
| 4 | |
| 5 | ## Audits |
| 6 | Working from the PageSnapshot (`rendered_dom` if present, else `raw_html`) and the raw HTML the server first returned: |
| 7 | 1. **Content delta**: diff `raw_html` vs `rendered_dom` — measure the share of primary text, internal links, headings (h1–h3), and `<script type="application/ld+json">` blocks that appear **only** after JavaScript runs. |
| 8 | 2. **Classify the strategy**: CSR-only (empty/near-empty raw shell, content injected client-side) / SSR / SSG (prerendered static) / ISR (prerendered + revalidated). Use raw-HTML completeness and framework signals (`__NEXT_DATA__`, hydration markers, `data-reactroot`, build manifests). |
| 9 | 3. **Hydration-blocked text**: primary content present in raw HTML but hidden/empty until hydration, or rendered only into a client-only island. |
| 10 | 4. **Lazy-loaded main content**: above-the-fold or primary content that requires scroll/intersection/interaction to load — invisible to a non-interacting crawler. |
| 11 | 5. **AI gate**: if the h1, primary body, or JSON-LD exist only in `rendered_dom`, flag the page as not reliably consumable by non-JS AI crawlers. |
| 12 | |
| 13 | ## Fixes (fixable: advisory) |
| 14 | Rendering strategy is a framework/architecture decision with high breakage risk, so M4 is **ADVISORY only** — it diagnoses and prioritizes, it never auto-edits build/server code. |
| 15 | - Emit framework-specific guidance: e.g. move CSR-only routes to SSG/ISR or SSR (Next.js App Router server components / `generateStaticParams` + `revalidate`; Nuxt/Astro/SvelteKit equivalents). |
| 16 | - Recommend prerendering or partial prerendering for primary content; reserve client-only islands for genuinely interactive widgets. |
| 17 | - Where the right strategy depends on data freshness or constraints the snapshot can't reveal, leave a clearly-marked TODO for the user — **never** fabricate a `revalidate` interval or assert a strategy choice. Every finding carries `fixable: advisory`. |
| 18 | |
| 19 | ## Verification |
| 20 | - `render_diff`: compute the content-delta ratio of `raw_html` vs `rendered_dom` (primary text / links / headings / JSON-LD present in rendered but absent in raw). A high delta on primary content confirms the JS dependency. |
| 21 | - Rendering an accurate `rendered_dom` requires a headless-browser data tier. When that tier is unavailable, status is `needs_api` — never a false `pass`. |
| 22 | |
| 23 | ## Findings |
| 24 | Emit findings per `schema/finding.schema.json`. Examples: |
| 25 | - `M4.render.csr_only_primary_content` — h1 and body text exist only in `rendered_dom`, raw HTML is an empty shell (status `fail`, severity 5, axis `both`, `fixable: advisory`, confidence `established`). |
| 26 | - `M4.render.jsonld_js_injected` — JSON-LD blocks present only after hydration, so non-JS crawlers see no structured data (status `warn`, severity 4, axis `ai`, `fixable: advisory`, confidence `established`). |
| 27 | - `M4.render.lazy_main_content` — primary content loads only on scroll/interaction (status `warn`, severity 4, axis `both`, `fixable: advisory`, confidence `directional`). |
| 28 | Each finding: `evidence.observed` quotes the raw vs rendered delta on the page; `verification.reproduce` is a runnable `render_diff` assertion; `expected_impact` is banded + confidence-tagged (no naked %). |
| 29 | |
| 30 | ## Honesty |
| 31 | - Googlebot **does** render JavaScript (second-wave, queued), so a well-built CSR app can still rank in classic Search — frame CSR-only as an AI-visibility and crawl-efficiency problem, not an automatic Google-ranking failure. |
| 32 | - Don't claim "SSR ranks higher than CSR" as a ranking factor; the documented effect is content **availability** to non-JS consumers and faster paint, not a rendering-mode boost. Keep CSR if the page is interactive-by-nature and primary content is still server-delivered. |