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com.postboxservices/postbox-tools

by postboxservices.com · remote · no sign-in to list tools · v0.1.1 · published by com.postboxservices

Free email checks: 24 blacklists, spoofing/BEC grade, redirect tracing, email spam test, WHOIS.

Changes · 5
CompareRegistry entry

8 tools: 5 change things and 3 only read.

Scanned Oct 21, 2026

1 check matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http postbox-tools https://mcp.postboxservices.com/mcp

Findings

Matches of fixed checks, with the text they matched.

1 warn
  • Warnanalyze_eml

    The server marks "analyze_eml" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

    Matched text

    annotations: {"readOnlyHint":true}; The name "analyze_eml" says "analyze": a word for reading.

    What this check looks for

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

8 tools

Changes things 5Claude Code: ask
  • analyze_emlRun a deliverability/content analysis on a raw RFC 822 email (.eml source: full headers + body).1 finding

    Why it is in this group

    • The name "analyze_eml" says "analyze": a word for reading.
    • The description's first verb is "run": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

      The server marks "analyze_eml" read-only (readOnlyHint: true), and its own name, description or input give the class "write".

      Matched text

      annotations: {"readOnlyHint":true}; The name "analyze_eml" says "analyze": a word for reading.

      What this check looks for
    Description, as the server wrote it
    Run a deliverability/content analysis on a raw RFC 822 email (.eml source: full headers + body). IMPORTANT LIMITS: with no live SMTP session, SPF, blacklist and reverse-DNS cannot be verified from a file - for the authoritative score use create_mailtest instead.

    Annotations the server declares

    • title: Analyze a raw email file (.eml)
    • readOnlyHint: true
  • check_blacklistCheck a domain against domain blacklists (Spamhaus DBL, SURBL, URIBL and others), or an IP address against 24 IP blacklists including Spamhaus ZEN, Barracuda and SpamCop.No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Check a domain against domain blacklists (Spamhaus DBL, SURBL, URIBL and others), or an IP address against 24 IP blacklists including Spamhaus ZEN, Barracuda and SpamCop. Checks the exact target given: domains are not resolved to IPs. Returns per-list listing status.

    Annotations the server declares

    • title: Email blacklist check
    • readOnlyHint: true
  • check_spoofabilityGrade how exposed a domain is to email spoofing and business email compromise, from its public DNS (SPF, DMARC policy strength, alignment, live lookalike domains).No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Grade how exposed a domain is to email spoofing and business email compromise, from its public DNS (SPF, DMARC policy strength, alignment, live lookalike domains). Returns an A-F grade with findings.

    Annotations the server declares

    • title: Spoofing / BEC exposure check (A-F grade)
    • readOnlyHint: true
  • create_mailtestCreate a disposable test address for a full email deliverability audit (score /10: SPF, DKIM, DMARC + alignment, blacklists, reverse DNS, SpamAssassin content, Gmail/Yahoo bulk-sen…No findings

    Why it is in this group

    • The name "create_mailtest" says "create": a word for a change.
    Description, as the server wrote it
    Create a disposable test address for a full email deliverability audit (score /10: SPF, DKIM, DMARC + alignment, blacklists, reverse DNS, SpamAssassin content, Gmail/Yahoo bulk-sender compliance). The USER must then send an email from the system they want to test to the returned address, after which get_mailtest_result returns the score.

    Annotations the server declares

    • title: Start an email deliverability test
    • readOnlyHint: false
    • destructiveHint: false
  • trace_redirectFollow a URL server-side through every HTTP redirect hop to its real final destination - per-hop status, IP, TLS and timing, plus phishing/deliverability flags (cross-domain jumps,…No findings

    Why it is in this group

    • Nothing in its name or description says what it does, so it is counted as a write.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
    Description, as the server wrote it
    Follow a URL server-side through every HTTP redirect hop to its real final destination - per-hop status, IP, TLS and timing, plus phishing/deliverability flags (cross-domain jumps, https downgrades, meta/JS redirects). Fetching is SSRF-hardened (private ranges blocked, HTTPS-only, per-hop validation); how it works: https://redirect.postboxservices.com/

    Annotations the server declares

    • title: URL redirect chain tracer
    • readOnlyHint: true
Only reads 3Claude Code: allow
  • get_domain_ageGet a domain's registration date and age (young domains have weak sending reputation).No findings

    Why it is in this group

    • The name "get_domain_age" says "get": a word for reading.
    Description, as the server wrote it
    Get a domain's registration date and age (young domains have weak sending reputation).

    Annotations the server declares

    • title: Domain age lookup
    • readOnlyHint: true
  • get_mailtest_resultFetch the score and breakdown of a mail test created with create_mailtest, once the user has sent their email to the disposable address.No findings

    Why it is in this group

    • The name "get_mailtest_result" says "get": a word for reading.
    Description, as the server wrote it
    Fetch the score and breakdown of a mail test created with create_mailtest, once the user has sent their email to the disposable address.

    Annotations the server declares

    • title: Get an email deliverability test result
    • readOnlyHint: true
  • whois_lookupWHOIS summary for a domain: registrar, created/updated/expires dates, nameservers, DNSSEC, status flags.No findings

    Why it is in this group

    • The name "whois_lookup" says "lookup": a word for reading.
    Description, as the server wrote it
    WHOIS summary for a domain: registrar, created/updated/expires dates, nameservers, DNSSEC, status flags.

    Annotations the server declares

    • title: WHOIS lookup
    • readOnlyHint: true

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Install

Pinned to version 0.1.1. Values in angle brackets are yours to fill in.

claude mcp add --transport http postbox-tools https://mcp.postboxservices.com/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__postbox-tools__get_mailtest_result",
      "mcp__postbox-tools__get_domain_age",
      "mcp__postbox-tools__whois_lookup"
    ],
    "ask": [
      "mcp__postbox-tools__check_blacklist",
      "mcp__postbox-tools__check_spoofability",
      "mcp__postbox-tools__trace_redirect",
      "mcp__postbox-tools__create_mailtest",
      "mcp__postbox-tools__analyze_eml"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. It assumes the server is installed as postbox-tools. Review it before you use it.