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    Email Auth Deliverability Doctor

    Email Auth Deliverability Doctor

    by JustHandled Labs

    Audit your SPF, DKIM, and DMARC records for the misconfigurations that get mail rejected or sent to spam. Flags a missing DMARC record or p=none, missing rua reporting, a missing or duplicated SPF record, SPF over the 10-lookup limit, permissive +all/?all, a missing DKIM selector, and SPF/DKIM domain-alignment mismatches. Paste a DNS zone file or dig/nslookup output.

    Updated Jun 2026
    Security scanned
    Cursor

    $12

    · or 60 credits

    30-day refund guarantee

    Secure checkout via Stripe

    Included in download

    • Identify SPF records exceeding the 10-lookup limit
    • Detect missing or misconfigured DMARC enforcement policies
    • terminal, file_read automation included
    • Ready for Cursor
    • Instant install

    Sample input

    Audit the following DNS records for my domain and tell me why my emails are landing in spam: v=spf1 include:_spf.google.com include:sendgrid.net ~all and v=DMARC1; p=none;

    Sample output

    Audit Findings

    • Rule ID: SPF-MULTIPLE-INCLUDE
    • Severity: High
    • Finding: SPF record looks valid but DMARC is set to p=none.
    • Evidence: p=none provides no protection against spoofing.
    • Remediation: Once delivery is confirmed, upgrade DMARC to p=quarantine.

    About This Skill

    What it does

    The Email Auth Deliverability Doctor is a diagnostic tool designed to audit SPF, DKIM, and DMARC records for common misconfigurations that lead to high bounce rates and spam folder placement. It analyzes DNS zone files, dig outputs, or nslookup text to identify technical errors and alignment issues.

    Why use this skill

    Manually debugging email authentication records is error-prone. This skill automates the process by checking your records against a comprehensive audit checklist. It helps you catch syntax errors, multiple SPF records, missing DMARC policies, and misalignment between signing domains and sender addresses without the risk of an automated tool making unauthorized changes to your live DNS.

    Supported inputs

    • DNS zone file exports
    • Terminal output from dig or nslookup
    • Local DNS configuration text files

    What the output looks like

    The skill produces a structured audit report including the specific rule violated, the severity of the issue, direct evidence from your records, and clear remediation guidance to fix the deliverability problem.

    Use Cases

    • Identify SPF records exceeding the 10-lookup limit
    • Detect missing or misconfigured DMARC enforcement policies
    • Verify DKIM selector alignment across DNS zone exports
    • Troubleshoot why legitimate emails are being rejected by major providers

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    Security Scanned

    Passed automated security review

    Permissions

    Terminal / Shell
    Read Files

    File Scopes

    email-auth-deliverability-doctor/**
    **/*.zone
    **/*.dns
    **/dns*.txt
    **/*dig*.txt

    Also accepts pasted records via --stdin. Read-only, standard library only, no environment variables.

    Tags

    email-deliverability
    dns-audit
    postmaster
    devops
    sysadmin

    Works with any agent that can read a file and run a local Python script (Claude Code, Cursor, Codex CLI, and other SKILL.md-compatible agents). Standard library only, no install step. Reads zone/dig text from a file or stdin. It does not perform live DNS queries, so you supply the records.

    Creator

    JustHandled Labs

    JustHandled Labs creates focused agent skills and workflow packs for Claude, Codex, Cursor, and AI-assisted builders. Each tool is designed around a real repeatable task: cleaner commits, better PRs, stronger handoffs, safer repo hygiene, clearer documentation, and less copy-paste chaos. The goal is not generic AI productivity. The goal is specific workflows that are easier to run, review, and repeat. Maintained by H.J. Westerfield, with a background in communications, editing, project coordination, customer support, and practical AI systems. JustHandled Labs builds tools for people who want useful automation without theatrical complexity.

    Frequently Asked Questions

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