SEO Drift Monitor (April 2026)

SEO Drift Monitor (April 2026)

Git for your SEO. Capture baselines, detect regressions, track changes over time.

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Commands

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What It Captures

Every baseline records these SEO-critical elements:

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How Comparison Works

The comparison engine applies 17 rules across 3 severity levels. Load references/​comparison-rules.md for the full rule set with thresholds, recommended actions, and cross-skill references.

Severity Levels

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Storage

All data is stored locally in SQLite:

~/​.cache/​claude-seo/​drift/​baselines.db

Tables

• baselines: Captured snapshots with all SEO elements
• comparisons: Diff results with triggered rules and severities

URL normalization ensures consistent matching: lowercase scheme/​host, strip default ports (80/​443), sort query parameters, remove UTM parameters, strip trailing slashes.

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Command: baseline

Captures the current state of a page and stores it.

Steps:

1. Validate URL (SSRF protection via google_auth.validate_url())
2. Fetch page via scripts/​fetch_page.py
3. Parse HTML via scripts/​parse_html.py
4. Optionally fetch CWV via scripts/​pagespeed_check.py (use --skip-cwv to skip)
5. Hash HTML body and schema content (SHA-256)
6. Store snapshot in SQLite

Execution:

python3 scripts/​drift_baseline.py <url>
python3 scripts/​drift_baseline.py <url> --skip-cwv

Output: JSON with baseline ID, timestamp, URL, and summary of captured elements.

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Command: compare

Fetches the current page state and diffs it against the most recent baseline.

Steps:

1. Validate URL
2. Load most recent baseline from SQLite (or specific --baseline-id)
3. Fetch and parse current page state
4. Run all 17 comparison rules
5. Classify findings by severity
6. Store comparison result
7. Output JSON diff report

Execution:

python3 scripts/​drift_compare.py <url>
python3 scripts/​drift_compare.py <url> --baseline-id 5
python3 scripts/​drift_compare.py <url> --skip-cwv

Output: JSON with all triggered rules, old/​new values, severity, and actions.

After comparison, offer to generate an HTML report:

python3 scripts/​drift_report.py <comparison_json_file> --output drift-report.html

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Command: history

Shows all baselines and comparisons for a URL.

Execution:

python3 scripts/​drift_history.py <url>
python3 scripts/​drift_history.py <url> --limit 10

Output: JSON array of baselines (newest first) with timestamps and comparison summaries.

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Cross-Skill Integration

When drift is detected, recommend the appropriate specialized skill:

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Error Handling

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Security

• All URL fetching goes through scripts/​fetch_page.py which enforces SSRF protection (blocks private IPs, loopback, reserved ranges, GCP metadata endpoints)
• No curl, no subprocess HTTP calls -- only the project's validated fetch pipeline
• All SQLite queries use parameterized placeholders (?), never string interpolation
• TLS always verified -- no verify=False anywhere in the pipeline

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Typical Workflows

Pre/​Post Deployment Check

/​seo drift baseline https://example.com     # Before deploy
# ... deploy happens ...
/​seo drift compare https://example.com      # After deploy

Ongoing Monitoring

/​seo drift baseline https://example.com     # Initial capture
# ... weeks later ...
/​seo drift compare https://example.com      # Check for drift
/​seo drift history https://example.com      # Review all changes

Investigating a Traffic Drop

/​seo drift compare https://example.com      # What changed?
/​seo drift history https://example.com      # When did it change?