🤔 Don't know what an MCP is? Read this 30-second explainer
Model Context Protocol (MCP) is the open standard that lets AI assistants like Claude, Cursor, or Codex call external tools. Think of it as "USB for AI assistants" — you plug a tool in, the AI can use it. librecrawl-technical-seo-audit-mcp is one of those tools. Once installed, you just ask your AI assistant to audit a site, and it does. No GUI. No dashboard. No exports.
New to all this?
🪄 The whole pitch in 4 lines
You: Audit https://acme.com — full site, no caps, give me the zip
Agent: → librecrawl_start_chunked_audit · polls until done · saves zip locally
You: Show me broken pages + broken external links + hreflang errors
Agent: → reads CSVs, prints filtered tables. Server already forgot the audit.
That's the product. Your AI assistant runs a full technical SEO audit for you. You get a branded PDF + 7 CSVs covering 50+ technical checks, ready to hand a client. The server wipes everything the moment you download.
🔥 Why this exists
There are great desktop SEO crawlers (you know the ones). There are great cloud SEO suites. There was no AI-native crawler. librecrawl-technical-seo-audit-mcp fills that gap with five things no comparable open-source MCP server does:
⚡ It runs inside your AI assistant
37 MCP tools your agent calls directly. No GUI app to babysit, no SaaS dashboard to log into, no CSV exports to upload to ChatGPT. You just ask.
🚀 Chunked-progressive crawler that never times out
Most SEO MCP servers (SiteAudit MCP, AgentAEO, SE Ranking MCP) run synchronously and disconnect on sites over a few hundred pages. librecrawl-technical-seo-audit-mcp runs the crawl in a background worker thread, persists progress to SQLite WAL, and returns a session_id in under 2 seconds. Your agent polls a tiny status tool until done. 10,000-page enterprise sites work the same as 50-page blogs. Survives PM2 / MCP-client restarts mid-crawl.
🛡️ Catches WAF challenges other crawlers silently misreport
Cloudflare, Akamai, DataDome, Imperva, and PerimeterX challenge pages are served as 200 OK but contain a JavaScript challenge instead of your content. Most crawlers report these as "page OK, all good". librecrawl-technical-seo-audit-mcp fingerprints the challenge in the response body and flags bot_block_challenge_detected. You see what's actually broken.
🤖 An AIMD controller tunes crawl delay live
Additive-Increase / Multiplicative-Decrease — the same algorithm TCP congestion control uses. Error rate > 10% → halve chunk, double delay. p95 latency > 1.5× target → 1.5× delay. Clean signals → additive decrease. Polite by construction. No rate-limit blow-ups. No manual tuning. Respects robots.txt Crawl-Delay floor.
🧹 Ephemeral by design — the agency-safe default
Once you download the zip, the server deletes the session row, every artifact file on disk, AND the upstream LibreCrawl crawl record. Per-audit server footprint after cleanup: 0 bytes, 0 rows. Auditing 50 client sites? Zero data persists where another operator could see it.
📄 Branded PDF reports ready to hand a client
WeasyPrint, A4, page numbers, footer on every page. Open in any PDF viewer. No SaaS watermark. Hand it to a client as your work.
⚡ Install in 60 seconds
curl -fsSL https://raw.githubusercontent.com/adityaarsharma/librecrawl-technical-seo-audit-mcp/main/install.sh | bash
The installer asks 3 questions (target client, optional Google PageSpeed API key, optional GSC integration) and writes a ready-to-use MCP entry into your Claude / Cursor / Codex / Windsurf config. Done.
What if I'm not a developer?
You don't need to be. If you can:
- Open a terminal (macOS: Cmd+Space → "Terminal" · Windows: Win+R → "powershell")
- Paste the
curl command above
- Answer 3 yes/no questions
…you're done. The installer handles Python, Docker, the LibreCrawl backend, and your AI client config. First-audit-to-zip is under 10 minutes from cold start.
Manual install (Python 3.10+, Docker for LibreCrawl backend)
git clone https://github.com/adityaarsharma/librecrawl-technical-seo-audit-mcp.git
cd librecrawl-technical-seo-audit-mcp
python3 -m venv venv && source venv/bin/activate
pip install httpx mcp weasyprint markdown fpdf2
# Start LibreCrawl backend on :5080 (see install.sh for Docker compose)
python server.py
Add to your client config (Claude Desktop example):
{
"mcpServers": {
"librecrawl": {
"command": "npx",
"args": ["-y", "mcp-remote", "http://127.0.0.1:5081/mcp"]
}
}
}
🚀 50+ checks every audit
🔒 Security & headers
missing_hsts · missing_csp · missing_x_frame_options · missing_x_content_type_options · missing_referrer_policy · x_robots_tag_vs_meta_mismatch · mixed_content
🛡️ WAF / bot-block detection
bot_block_challenge_detected — fingerprints Cloudflare · Akamai · DataDome · Imperva · PerimeterX
🗺️ Sitemap & robots
sitemap_url_noindex · sitemap_url_3xx · sitemap_url_disallowed_in_robots · sitemap_contains_canonicalized · sitemap_over_50k_urls · sitemap_over_50mb
🌍 Hreflang full audit
missing_return_tag · missing_self_reference · missing_x_default · invalid_codes · to_noindex · to_broken · conflicts_lang_attr
🔗 Canonical health
canonical_chain_depth · canonical_to_relative · canonical_to_redirect · canonical_outside_head · bad_canonical
🔁 Redirects (every flavour)
redirect_chains · meta_refresh_redirect · js_redirect · http_refresh_redirect
🏷️ Schema.org (16 types)
Article · Product · Recipe · FAQPage · BreadcrumbList · Event · JobPosting · VideoObject · HowTo · Organization · LocalBusiness · Person · Review · AggregateRating · Course · NewsArticle — validates schema.org spec AND Google Rich Results required fields. Handles @graph (Yoast / Rank Math / WPRM).
|
🔤 URL quality
url_contains_space · url_multiple_slashes · url_non_ascii · url_underscores · url_repetitive_path · long_urls · uppercase_urls · url_params_heavy
⚓ Anchor text
non_descriptive_anchor_text · empty_anchor_text · anchor_image_no_alt · broken_bookmarks
🕸️ Internal linking
internal_nofollow_outlinks · nofollow_only_inbound · follow_and_nofollow_mixed · orphan_pages
🖼️ Image performance + CLS
lazy_load_attr_missing · srcset_missing · image_dimensions_missing · next_gen_image_format · image_oversized_kb · missing_alt_pages · broken_img_pages
📐 HTML structure
html_over_2mb · noscript_in_head · broken_or_invalid_html · dom_size_excessive · lorem_ipsum_detected
♿ Accessibility / metadata
iframes_present · iframe_missing_title · missing_favicon · missing_html_lang · invalid_html_lang · missing_charset · missing_viewport
🪤 Crawl-budget killers
spider_trap_calendar · url_session_id_high_entropy · faceted_url_explosion
✍️ Content quality
low_readability (Flesch) · long_sentences · passive_voice_pct · missing_terminal_punctuation · boilerplate_ratio · ai_tell_tokens_found (delve · unlock · seamlessly · leverage) · has_lorem_ipsum
🚨 Dev leaks
outlinks_to_localhost (RFC1918 in production)
|
🔗 Every outbound URL HEAD/GET-validated into 17 status classes — ok · redirect · forbidden · not_found · timeout · dns_error · ssl_error · connection_refused · etc. Per-target: final URL after redirects, source pages, anchor text, response time, server header.
📈 GSC merge — pull Google Search Console data, call librecrawl_merge_gsc_data(crawl_id, gsc_data). URLs normalised before joining. Emits 4 extra CSVs: per-page-with-gsc · gsc-winners · gsc-losers (high impr + CTR <2%) · gsc-quick-wins (position 11–20 + impr ≥100).
🆚 Feature comparison to other on-site SEO crawlers
This is a factual feature comparison. Prices were checked at publication and may have changed — see each vendor's site for current pricing. Brand names belong to their respective owners.
| Capability | Desktop crawler (Screaming Frog SEO Spider™)1 | Desktop+cloud crawler (Sitebulb™)2 | Cloud site-audit (Ahrefs™)3 | librecrawl-technical-seo-audit-mcp |
|---|
| Pricing model | Free tier (500 URLs) · paid annual licence | Paid monthly subscription | Bundled with main subscription | Free, MIT-licensed, self-hosted |
| Page cap | 500 free / unlimited paid | Unlimited | Tiered by subscription plan | ♾️ Unlimited |
| Runs inside your AI assistant | ❌ | ❌ | ❌ | ✅ |
| Chunked / background crawl (no timeout) | ❌ | ❌ | Cloud only | ✅ |
| Auto-adaptive crawl delay (AIMD) | ❌ | Manual | Hidden | ✅ |
| WAF / bot-block detection on 200-OK pages | ❌ | ❌ | ❌ | ✅ |
| Sitemap-orphan fill (URLs not internally linked) | ❌ | ❌ | ❌ | ✅ |
| Ephemeral by default (zero server footprint) | N/A | N/A | N/A | ✅ |
| Broken links (4xx/5xx/timeout/DNS/SSL) | ✅ | ✅ | ✅ | ✅ |
| Redirect chains with destination | ✅ | ✅ | ✅ | ✅ |
| Title / meta / H1 + duplicates | ✅ | ✅ | ✅ | ✅ |
| Canonical full audit | ✅ | ✅ | ✅ | ✅ |
| Hreflang full audit (incl. return-tag graph) | ✅ | ✅ | Partial | ✅ |
| Sitemap full cross-checks | ✅ | ✅ | Partial | ✅ |
| Schema.org validation (16 types + Rich Results) | ✅ | ✅ | Partial | ✅ |
| Soft-404 fingerprinting | ✅ | ✅ | ✅ | ✅ |
| Mixed content (HTTPS → HTTP) | ✅ | ✅ | ✅ | ✅ |
| Security headers pack | ✅ | ✅ | Partial | ✅ |
| Image performance + CLS | ✅ | ✅ | ✅ | ✅ |
| Content quality (Flesch · AI-tells · boilerplate) | ❌ | Partial | ❌ | ✅ |
| Crawl-budget traps (calendar · session-id · facets) | ✅ | ✅ | ✅ | ✅ |
| Branded PDF report | ❌ | ✅ | ❌ | ✅ |
| GSC clicks/impressions merge | Paid add-on | Paid add-on | Native | ✅ |
| JavaScript rendering | ✅ | ✅ | Cloud only | 🛣️ Roadmap |
1 Screaming Frog SEO Spider is a trademark of Screaming Frog Ltd, UK. We are not affiliated.
2 Sitebulb is a trademark of Sitebulb Ltd, UK. We are not affiliated.
3 Ahrefs is a trademark of Ahrefs Pte. Ltd., Singapore. We are not affiliated.
Reading guide: if you currently use a paid on-site crawler and your workflow is "crawl → export CSVs → analyse", librecrawl-technical-seo-audit-mcp covers that flow inside your AI assistant for £0 with no page caps. If your workflow depends on JavaScript-rendered SPAs, that's on the roadmap but not shipped yet — use the desktop tool for now.
📊 What every audit produces
Single zip, 8 files:
| File | Use |
|---|
SUMMARY.txt | One-page orientation |
<domain>-<ts>.pdf | Branded human-readable PDF (open in any viewer) |
<domain>-<ts>.md | Markdown source of the PDF (grep-friendly) |
per-page.csv | 1 row per URL × 30 columns of check booleans + failed_checks_list |
sitemap-recon.csv | Sitemap-vs-crawl diff |
external-links.csv | Every outbound URL + status |
content-audit.csv | Per-page readability + AI-tells |
extended-checks.csv | 1 row per (URL × check × severity × detail) — all 50+ checks |
📖 Your first audit
You: Audit https://example.com — full site, no caps
Agent: → librecrawl_start_chunked_audit(url=..., total_max_pages=10000)
returns session_id in <2s
→ polls librecrawl_audit_status every 25s
status: crawling, pages_done: 47, current_delay_ms: 250
status: crawling, pages_done: 312, last chunk p95: 480ms, err_rate: 0%
status: done, pages_done: 534, artifacts_ready: true
→ librecrawl_audit_zip(session_id, auto_cleanup=True)
returns base64 zip (8 files, 320 KB)
SAVES LOCALLY as example.com-1780572742.zip
Server wiped: session_rows=4, files=8, upstream_crawl=1
You: Show me broken pages + broken external links
Agent: → unzips, reads per-page.csv (filters status_4xx OR status_5xx)
→ reads external-links.csv (filters not_found · forbidden · 5xx · timeout)
→ prints both tables
Local zip is the only copy. Server is back to zero state.
🛣️ Roadmap
| Status |
|---|
| JavaScript rendering (Playwright headless, DOM diff vs raw HTML) — catches SPA / React / Next.js apps | 🟡 Designed |
| Core Web Vitals from CrUX — real-user 28-day field data, not just lab PSI | 🟡 Designed |
| axe-core accessibility audit — contrast, ARIA, focus order, alt-text quality | 🟡 Planned |
White-label PDF theming (--brand-config for agencies) | 🟡 Planned |
| Diff mode — audit A vs audit B, "what regressed since last week?" | 🟡 Planned |
| Webhook on completion (Slack / Discord) — ping when long crawls finish | 🟡 Planned |
Not planned: keyword research, backlink analysis, SERP tracking. Those are different problems with different MCP servers (DataForSEO, etc.). This tool is laser-focused on technical on-site SEO crawling.
Open an issue to bump priorities or request a check.
🏗️ Architecture
┌─────────────────────────────────────────────────────────────┐
│ MCP client (Claude Code / Desktop / Cursor / Codex …) │
└────────────────────────────┬────────────────────────────────┘
│ streamable HTTP or stdio
▼
┌─────────────────────────────────────────────────────────────┐
│ librecrawl-technical-seo-audit-mcp wrapper (server.py — FastMCP, 37 tools) │
│ ┌─────────────────┐ ┌──────────────────────────────┐ │
│ │ runner.py │ │ external_links / schema / │ │
│ │ background │ │ content_audit / extended_ │ │
│ │ worker thread │ │ checks / sitemap_fill / │ │
│ │ AIMD controller │ │ pdf_report │ │
│ └────────┬────────┘ └──────────────────────────────┘ │
│ │ │
│ ┌────────▼────────┐ ┌──────────────────────────────┐ │
│ │ state.py │ │ libreclient.py — typed │ │
│ │ SQLite WAL │ │ wrapper to upstream API │ │
│ │ session state │ └──────────────┬───────────────┘ │
│ └─────────────────┘ │ │
└─────────────────────────────────────────┼────────────────────┘
│
▼
┌──────────────────────────────┐
│ LibreCrawl Flask backend │
│ :5080 — single-tenant │
│ crawls + extracts SEO data │
└──────────────────────────────┘
⚙️ Configuration
| Env var | Default | Purpose |
|---|
LIBRECRAWL_PORT | 5080 | LibreCrawl backend port |
MCP_PORT | 5081 | MCP wrapper port |
MCP_TRANSPORT | http | http (streamable) or stdio |
REPORTS_DIR | ~/librecrawl-reports | Where audit artifacts land |
PAGESPEED_API_KEY | unset | Optional — enables librecrawl_pagespeed* |
LIBRECRAWL_STATE_DB | ~/librecrawl-state.db | SQLite WAL state store |
🛠️ 37 MCP tools
Expand the full tool reference
Chunked audit (95% of work):
librecrawl_start_chunked_audit · librecrawl_audit_status · librecrawl_audit_ziplibrecrawl_audit_pause · librecrawl_audit_resume · librecrawl_audit_cancel · librecrawl_audit_force_advancelibrecrawl_audit_artifacts · librecrawl_audit_pdf · librecrawl_report_content
Specialist:
librecrawl_external_links_audit — re-run external-link validation on a specific crawllibrecrawl_schema_validate · librecrawl_schema_check · librecrawl_schema_auditlibrecrawl_merge_gsc_data · librecrawl_append_gsc_section — Google Search Console data mergelibrecrawl_pagespeed · librecrawl_pagespeed_audit · librecrawl_pagespeed_audit_all_crawl_pages — PageSpeed Insightslibrecrawl_site_check — instant site-level checklibrecrawl_internal_links_analysis · librecrawl_filter_issues · librecrawl_visualization_data
Maintenance:
librecrawl_wipe_everything — nuclear reset to zerolibrecrawl_brain_purge_audit — purge a single audit
Legacy (kept for backwards compat, avoid for big sites):
librecrawl_audit · librecrawl_full_audit_strict · librecrawl_generate_report · librecrawl_export_results · librecrawl_get_status · librecrawl_get_settings · librecrawl_list_crawls · librecrawl_start_crawl · librecrawl_stop_crawl · librecrawl_pause_crawl · librecrawl_resume_crawl · librecrawl_resume_from_crawl_id
📜 License & trademarks
Code: MIT. Use it on client work, agency work, internal tools, anything. No attribution required (but appreciated). See LICENSE.
Trademarks. All third-party product names mentioned in this README (including any names referenced in the comparison table) are property of their respective owners. This project is not affiliated with, endorsed by, or sponsored by any third-party tool vendor. Comparisons are based on publicly available information at the time of writing and exist for the purpose of informing readers evaluating different categories of SEO tooling.
🙏 Credits
- LibreCrawl — the upstream open-source crawler this MCP server wraps. MIT. Please go star them — this project would not exist without that work.
- Anthropic Model Context Protocol — the protocol this server speaks
- WeasyPrint — Markdown → HTML → PDF rendering
- FastMCP — the Python MCP server framework
Built by Aditya Sharma · MIT · No telemetry · No SaaS · No vendor lock-in
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