Detect SEO regressions across site changes

Capture SEO baselines and detect regressions via page-level diffs

Catching SEO regressions during site migrations, rewrites, or CMS updates where before/after diffs with triggered rules save investigation time.

• · target URL
• · optional: existing baseline ID (for targeted comparison)

• · baseline snapshot (title, meta, canonical, h1-h3, schema, OG, CWV, status code, HTML/schema hashes)
• · comparison diff report (triggered rules, old/new values, severity)
• · change history across all baselines and comparisons
• · HTML report with visual diff (optional)

• · fetch_page.py (HTML fetch)
• · parse_html.py (HTML parsing)
• · pagespeed_check.py (optional, CWV fetch)

• · target is live and accessible
• · SQLite directory ~/.cache/claude-seo/drift/ is writable

• · baseline not found — no prior snapshot exists, compare creates first baseline instead
• · CWV fetch fails (opt-in, --skip-cwv to bypass)
• · URL normalization mismatch — same page stored twice under different URL formats

• · 17 comparison rules across 3 severity levels (CRITICAL, WARNING, INFO)
• · 13-element baseline capture (title, meta, canonical, robots, h1-h3, schema, OG, CWV, status code, HTML hash, schema hash)
• · URL normalization (lowercase scheme/host, strip default ports 80/443, sort query params, remove UTM, strip trailing slashes)
• · SQLite storage with baselines and comparisons tables
• · git-style history tracking (all baselines per URL, newest first)
• · optional HTML diff report generation