MCP serverme.drwho/tools

Decode base64 to UTF-8 text. Accepts the standard and the URL-safe alphabet, with or without padding or line breaks. Fails when the input is not valid base64 or does not decode to

Encode UTF-8 text as base64. Set url_safe for the URL-safe alphabet (- and _ in place of + and /, no padding), as used in JSON Web Tokens. Runs locally. Returns the encoded string.

Resolve one DNS record type (A, AAAA, MX, TXT, NS, CNAME, SOA, CAA or SRV) for a name and return the raw answers. Use for a quick, targeted lookup, including on subdomains and name

Report what a domain's robots.txt says to the major AI crawlers (GPTBot, ClaudeBot, Google-Extended, PerplexityBot, CCBot, meta-externalagent): allowed, blocked or unspecified for

Send a CORS preflight (OPTIONS) to https://<domain>/ and return the access-control-* headers in the answer. Use to check whether a site accepts cross-origin requests from a given o

List subdomains of a domain that appear in Certificate Transparency logs. Use to map what hosts a domain has exposed through the certificates issued for it. Queries crt.sh, then ce

Probe a domain for DKIM public keys at <selector>._domainkey.<domain>. Pass selectors when you know them; omit to probe a built-in list of common selectors used by large mail provi

Find and parse the DMARC policy at _dmarc.<domain> into its tags (p, sp, pct, rua, ruf, adkim, aspf). Use to see whether spoofed mail is rejected, quarantined or only reported. Que

Fetch a domain's A, AAAA, NS, SOA, CAA and TXT records in one call. Use as the first step of a DNS review; prefer dns_lookup for a single record type or for MX, CNAME and SRV. Send

Check whether a domain's zone is signed with DNSSEC and validates: DS and DNSKEY records plus the resolver's AD (authenticated data) flag. Queries Cloudflare DNS-over-HTTPS with DO

Fetch https://<domain>/ and return every response header, so you can review Strict-Transport-Security, Content-Security-Policy, X-Frame-Options, X-Content-Type-Options, Referrer-Po

Check whether a domain publishes an llms.txt, the markdown index some sites provide for AI agents. Requires a non-HTML content type and a leading markdown heading, so a catch-all p

Fetch and validate a domain's MTA-STS policy (mode, mx, max_age). Use to confirm inbound mail to the domain must be delivered over TLS. Resolves the _mta-sts TXT record, then fetch

List a domain's MX (mail exchanger) records sorted by priority. Use to see where a domain's inbound mail goes, or before checking SPF and DMARC. Queries Cloudflare DNS-over-HTTPS,

Trace the redirect chain from https://<domain>/, one entry per hop with its status code and target, up to 10 hops. Use to debug redirect loops or confirm an HTTP to HTTPS or apex t

Check whether a domain publishes /.well-known/security.txt (RFC 9116), the standard way to tell researchers where to report a vulnerability. Returns the Contact and Expires fields.

Find and parse a domain's SPF record into its mechanisms. Use to check which servers may send mail for a domain, or to debug delivery failures; pair with dossier_dmarc and dossier_

Run the nine DNS, email-authentication and TLS checks on a domain in parallel and return one graded line per check: DNS records, MX, SPF, DMARC, DKIM, DNSSEC, TLS-RPT, MTA-STS and

Read the TLS certificate a domain presents on port 443: subject, issuer, validity dates, days remaining, subject alternative names, SHA-256 fingerprint and whether the chain valida

Look up a domain's SMTP TLS Reporting policy at _smtp._tls.<domain>. Use to confirm the domain receives reports about failed TLS delivery of its inbound mail. Queries Cloudflare DN

Summarise a domain's public web surface: robots.txt, sitemap.xml and the home page's title, description, OpenGraph and Twitter card tags. Use for a quick SEO or link-preview review

Look up a domain's registrar, creation date, expiry date and registry statuses. Use for an ownership or expiry check. Tries WHOIS over TCP port 43, then RDAP over HTTPS when the re

Look up an IPv4 or IPv6 address: city, region, country, coordinates, timezone and the network (ASN and organisation) that announces it. Use when you need location or ownership cont

Validate JSON and re-print it with an indent of 2 or 4 spaces, or minified with indent 0. Use to check whether a string is valid JSON or to make it readable. Runs locally. Returns

Decode a JSON Web Token's header and payload. It does NOT verify the signature, so never treat the claims as trusted on the strength of this tool. Use to inspect claims such as exp

Decode percent-encoded text. Fails on a malformed sequence such as a lone % sign. A plus sign is left as a plus; replace it with a space first if the text came from an HTML form. R

Percent-encode text for use in a URL query value or path segment (encodeURIComponent rules: everything except letters, digits and - _ . ! ~ * ' ( ) is encoded). Runs locally. Retur

Parse a User-Agent header into browser, operating system, device and rendering engine. Use when reading server logs or request headers. Runs locally with no network call. Returns J

Generate UUIDs. Version 4 is fully random. Version 7 starts with a millisecond timestamp, so values sort by creation time, which suits database keys. Runs locally with a cryptograp