MCP Toolbelt

A small set of pay-per-call tools, exposed over MCP and metered with thex402 protocol. No API key, no signup — pay in USDC on Base as you call.

Tools available (19)

Page & HTTP

url_to_markdown $0.0001 — fetch a URL, return cleaned readable text.
security_headers_audit $0.0002 — audit HSTS/CSP/X-Frame-Options and other security headers, with a score.
redirect_chain_check $0.0002 — follow every redirect hop, flag loops and HTTPS→HTTP downgrades.
page_performance_check $0.0002 — TTFB, total fetch time, response size, compression/cache-control checks.
cors_policy_check $0.0002 — probe CORS response headers, flag wildcard+credentials and origin reflection.
tech_stack_fingerprint $0.0002 — best-effort CMS/framework detection from headers and HTML markers.
ssl_cert_check $0.0002 — TLS certificate expiry, issuer, and subject for a host.
check_open_ports $0.0003 — TCP-connect scan of common (or specified) ports on a host.
websocket_endpoint_check $0.0002 — test a ws:// / wss:// handshake, report time-to-open and close code.
broken_link_check $0.001 — crawl a site (same-origin, bounded) and report broken links.

SEO & metadata

seo_audit $0.0003 — title/description, canonical, Open Graph & Twitter Card, lang, viewport, heading structure, alt-text coverage, link analysis, robots meta, structured data, and a score.
check_robots_sitemap $0.0001 — fetch and return a site's robots.txt and sitemap.xml contents.
favicon_manifest_check $0.0001 — favicon, apple-touch-icon, web app manifest, and theme-color presence.
json_ld_schema_validator $0.0002 — validate JSON-LD blocks against common schema.org type requirements.
sitemap_url_validator $0.0005 — parse sitemap.xml (incl. sitemap-index) and check every listed URL's status.

DNS, domain & email

domain_health_check $0.0005 — WHOIS expiry plus nameserver/A/MX/SPF/DMARC sanity checks.
dns_propagation_check $0.0003 — compare a record across Google/Cloudflare/Quad9/OpenDNS resolvers.
ip_geolocation_asn_lookup $0.0003 — ASN, network prefix, and country for a hostname's IPs (Team Cymru, no API key).
email_deliverability_check $0.0007 — MX/PTR, DKIM selector probing, SPF lookup-count, DMARC policy, and DNSBL blacklist checks.

Connect (pay-per-call, no key)

Each tool has its own endpoint, gated by x402 on theBase network. The first request comes back 402 Payment Required with payment details; an x402-aware HTTP client pays and retries automatically.

POST https://papacasper.com/mcp/pay/{tool}
Content-Type: application/json

{"url": "https://example.com"}

Price varies per tool, from $0.0001 to $0.001, paid in USDC on Base — see the price next to each tool above. Replace {tool} with any tool name listed above, e.g. seo_audit or ssl_cert_check.

Any x402-compatible client works — see thex402 docsfor client libraries that handle the 402 → pay → retry flow for you.

MCP clients

The same tools are also reachable as a standard MCP server over JSON-RPC at https://papacasper.com/mcp/ (methods: initialize,tools/list, tools/call). This endpoint is currently access-restricted — reach out if you'd like a key for higher-volume or client-based (Claude, ChatGPT, etc.) use.

WebMCP (in-browser agents)

The homepage also registers two tools via the draftWebMCPstandard (navigator.modelContext, Chrome 146+): an agent browsing the page in-session can call list_products_and_linksor subscribe_email directly, no separate connection needed.