Email deliverability checks: SPF, DKIM, DMARC, BIMI, MTA-STS, blacklists, headers, spam words
Scored across 5 tools
Each tool targets a distinct layer of email diagnostics: headers, IP/domain blacklists, whole-domain audit, single DNS record, and content scanning. However, check_domain is an aggregate that subsumes check_record and check_blacklists, so an agent may occasionally pick the broad tool when the narrow one was requested (or vice versa); the descriptions do mitigate this by explicitly framing check_domain as the 'start here' aggregator.
All five tools follow a clean snake_case verb_noun pattern (analyze_headers, check_blacklists, check_domain, check_record, check_spam_words). The shared 'check_' prefix groups four closely related diagnostics, and 'analyze_' is still a verb-noun form, so there is no convention mixing.
Five tools is well-scoped for an email-diagnostics server, with each tool earning its place as a distinct diagnostic capability. No redundant or filler tools are present.
The surface covers header/authentication forensics, IP and domain blacklist status, full domain authentication scoring with prioritized fixes, individual record lookup, and content spam scoring — a solid lifecycle for auditing email sendability. Minor gaps remain (no outbound SMTP/port-connectivity test, no PTR/rDNS or sending-IP reputation check as a standalone tool, no blacklist delisting help), but agents can largely work around these.
Parse raw email headers: the Received delivery path with per-hop delays, the receiving server's SPF/DKIM/DMARC verdicts, DMARC alignment of the From domain, DKIM signatures, the sending IP, and bulk-sender requirements such as one-click unsubscribe.
Inputs: headers (required).
Check an IPv4 address against about 18 IP blacklists (SpamCop, Barracuda, UCEPROTECT, PSBL, Mailspike, ...) or a domain against domain blacklists. Each list is verified with its test entries first, so lists that refuse public resolvers (such as Spamhaus) are reported as unavailable rather than clean.
Inputs: target (required).
Run every email-authentication check on a domain (SPF, DKIM, DMARC, MX, MTA-STS, TLS-RPT, BIMI, plus domain and mail-server blacklists) and return a score out of 100, per-check findings and a prioritized fix list. Use this first when asked whether a domain is set up correctly to send email.
Inputs: domain (required), dkim_selector.
Look up and validate a single email DNS record for a domain, explaining each tag. record is one of spf, dmarc, dkim, bimi, mta-sts, tls-rpt, mx. SPF counts the 10-lookup limit; DMARC checks policy, reporting and external report authorization; DKIM sizes the key; MTA-STS fetches the policy file and compares it with the MX hosts; BIMI checks the logo (SVG Tiny PS) and mark certificate.
Inputs: domain (required), record (required), policy, selector.
Scan an email subject and body (plain text or HTML) for spam-trigger phrases by category, ALL-CAPS, exclamation runs, emoji, URL shorteners and image-heavy HTML. Returns a low/medium/high risk reading and, optionally, a rule-based rewrite.
Inputs: body, rewrite, subject.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
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Check any domain's email deliverability: MX, SPF, DKIM, DMARC, MTA-STS, TLS-RPT, BIMI, blacklists.
Email deliverability check: MX, SPF, DKIM, DMARC, blacklists, MTA-STS, DNSSEC, BIMI. Graded, no key.
Domain checks: SPF, DKIM, DMARC, BIMI, MTA-STS, SSL/TLS and HTTP security headers.
Check SPF/DKIM/DMARC/BIMI, blacklists, SMTP/IMAP; DNS lookups; generate email DNS records.
Add one secure layer between your agents and this server.
