| name | seo-migration-check |
| description | Validate SEO preservation during site migrations. Checks redirect chains (301 vs 302, hop count), canonical consistency, title/meta preservation, HTTP status codes, content similarity, and schema preservation. Accepts single URL pair or CSV file of URL pairs. Use when user says "migration check", "site migration", "redirect audit", "URL mapping", "domain change", "relaunch", "site move".
|
| allowed-tools | ["Read","Bash","Glob","WebFetch"] |
Site Migration SEO Validator
Validates redirect chains, canonical tags, metadata, and content preservation during site migrations.
Inputs
Either:
old and new: Two URLs for a single-page check (e.g., https://old.com/page https://new.com/page)file: Path to CSV/text file with URL pairs, one per line: old_url,new_url
If file provided: Read it and process each line. Skip blank lines and lines starting with #.
For large files (>50 URL pairs), process first 50 and note truncation.
Execution
For each URL pair, run checks a-f:
Check a: Redirect Chain Validation
Fetch old URL with WebFetch and follow redirects (track each hop):
- Record redirect type: 301 (permanent), 302 (temporary), 307, 308
- Count redirect hops
- Record final destination URL
Evaluate:
- Final destination matches expected
new URL: PASS — mismatch: FAIL
- Redirect type is 301: PASS — 302/307: WARN (temporary redirects pass less link equity)
- Hop count 1: PASS — hop count 2: WARN — hop count >2: FAIL (redirect chain too long)
- Direct 200 on old URL (no redirect): FAIL (old page still live, not redirected)
Check b: Canonical Consistency
Fetch new URL, extract <link rel="canonical" href="..."> from <head>.
- Canonical matches new URL exactly: PASS
- Canonical missing: WARN (Google will infer, but explicit is better)
- Canonical points to old URL: FAIL (critical — tells Google old is authoritative)
- Canonical points to third URL: WARN
Check c: Title and Meta Preservation
Compare title and meta description between old URL (before redirect) and new URL.
Note: old URL may already redirect, so if old URL is not directly fetchable, skip comparison and note.
If comparable:
- Title: Extract both. Compare word overlap.
-
70% word overlap: PASS
- 40-70% overlap: WARN (may be intentional change)
- <40% overlap: WARN with note ("significant title change — verify this was intentional")
- Meta description: Extract both.
- Present on both: PASS
- Missing on new URL: WARN
- Both missing: NOTE
Check d: HTTP Status
Verify new URL returns 200 OK:
- 200: PASS
- 301/302 (new URL also redirects): WARN with destination
- 404: FAIL
- 500/5xx: FAIL
Check e: Content Similarity
If both old and new pages are fetchable, compare word counts:
- New page word count >= 80% of old: PASS
- New page word count 50-80% of old: WARN (possible content reduction)
- New page word count < 50% of old: FAIL (significant content loss)
If old URL not directly fetchable (already redirects): skip and note.
Check f: Schema Preservation
Extract @type values from JSON-LD blocks on both pages.
- Same schema types present: PASS
- Schema types reduced: WARN (lost structured data)
- Key schema missing on new (e.g., Product, Article, LocalBusiness): WARN
- No schema on either: NOTE (not a regression)
Overall Per-URL Result
FAIL: any check is FAIL
WARN: no FAILs but any check is WARN
PASS: all checks PASS or NOTE
Output Format
## Migration Validation: [old URL] → [new URL]
(or: ## Migration Validation: [N] URL pairs from [filename])
### Summary
| Status | Count |
|--------|-------|
| PASS | N |
| WARN | N |
| FAIL | N |
| Total | N |
### Per-URL Results
| Old URL | New URL | Redirect | Canonical | Title | Meta | Status Code | Schema | Overall |
|---|---|---|---|---|---|---|---|---|
| /old | /new | 301✓ | PASS | PASS | WARN | 200 | PASS | WARN |
### Failed Items Detail
For each FAIL result, expanded information:
**[old URL] → [new URL]**
- Redirect: [issue description]
- Canonical: [issue description]
- [etc.]
- Recommended fix: [specific action]
### Recommendations
[Prioritized list of actions based on failures and warnings]
## Data Sources
- Live URL fetching via WebFetch
- Redirect chain analysis (following HTTP headers)
