From email-deliverability
Diagnoses and fixes email deliverability issues by checking SPF, DKIM, DMARC, BIMI records, blacklist status, and SMTP/IMAP server connectivity. Generates DNS records for email authentication. Activates when the task involves email going to spam, domain reputation, DNS authentication setup, mail server configuration, sender verification, or email infrastructure troubleshooting.
npx claudepluginhub mailwarm/mailx-skills --plugin email-deliverabilityThis skill uses the workspace's default tool permissions.
Use the MailX MCP tools (`mailx` server) to diagnose, audit, and fix email authentication and delivery issues.
Triggers research for existing libraries, tools, and patterns before coding new features. Searches npm, PyPI, MCP/skills, GitHub; evaluates matches and decides adopt/extend/build.
Audits cross-stack repos (C++/Android/iOS/Web), classifies files as project/third-party/artifacts, detects embedded libraries, assigns module verdicts, generates interactive HTML reports.
Reorganizes X and LinkedIn networks: review-first pruning of low-value follows, priority-based add/follow recommendations, and drafts warm outreach in user's voice.
Share bugs, ideas, or general feedback.
Use the MailX MCP tools (mailx server) to diagnose, audit, and fix email authentication and delivery issues.
All tools are on the mailx MCP server. Use fully qualified names (mailx:tool-name):
| Tool | Purpose |
|---|---|
mailx:bimi-check | Check if a domain has a valid BIMI (Brand Indicators for Message Identification) DNS record. BIMI allows brands to display their logo next to authenticated emails in supporting email clients. |
mailx:bimi-host | Host and serve your BIMI SVG file for email authentication |
mailx:blacklist-check | Check if a domain or IP address is listed in popular email blacklists (DNSBLs). Being blacklisted can severely impact email deliverability. |
mailx:dkim-check | Check if a domain has a valid DKIM (DomainKeys Identified Mail) DNS record for a given selector. DKIM allows the receiver to verify that an email was sent by the domain owner. |
mailx:dmarc-check | Check if a domain has a valid DMARC (Domain-based Message Authentication, Reporting & Conformance) DNS record. DMARC tells receiving servers what to do with emails that fail SPF or DKIM checks. |
mailx:dmarc-generate | Generate a DMARC DNS record for a domain. Returns the record name, value, and type ready to be added to DNS. |
mailx:imap-check | Test an IMAP server connection by attempting to connect and authenticate. Use this to verify email receiving configuration. |
mailx:imap-finder | Look up IMAP server settings (host, port, encryption) for a given email provider. Use this to find the correct IMAP configuration for services like Gmail, Outlook, Yahoo, etc. |
mailx:smtp-check | Test an SMTP server connection by attempting to connect and authenticate. Optionally sends a test email to verify full sending capability. |
mailx:smtp-finder | Look up SMTP server settings (host, port, encryption) for a given email provider. Use this to find the correct SMTP configuration for services like Gmail, Outlook, SendGrid, etc. |
mailx:spf-check | Check if a domain has a valid SPF (Sender Policy Framework) DNS record. SPF specifies which mail servers are authorized to send email on behalf of a domain. |
mailx:spf-generate | Generate an SPF DNS record for a domain based on the email provider being used. Returns the record name, value, and type ready to be added to DNS. |
When diagnosing why emails go to spam or auditing a domain's setup:
Audit Progress:
- [ ] Run DNS checks (SPF, DMARC, DKIM)
- [ ] Check blacklist status
- [ ] Analyze combined results
- [ ] Generate missing records
- [ ] Report findings with fixes
mailx:spf-check, mailx:dmarc-check, and mailx:dkim-check for the domain. For DKIM, ask for the selector if unknown — try common ones: google, default, selector1, selector2, k1.mailx:blacklist-check.mailx:spf-generate or mailx:dmarc-generate.When setting up email authentication from scratch:
mailx:spf-generate using their provider.mailx:dmarc-generate — default to none policy, recommend upgrading to quarantine/reject after monitoring.When a user has issues sending or receiving email:
mailx:smtp-finder or mailx:imap-finder.mailx:smtp-check or mailx:imap-check using their credentials.include: into one.google, selector1/selector2, k1, default.p=none → monitor → p=quarantine → p=reject. Always include rua=.