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PopNx MCPMCP servers for people who use AI · explained in plain words

Postbox Tools

by postboxservices.comversion 0.2.0i★ –iRuns in the cloud
Registry namecom.postboxservices/postbox-tools

How to install

Overview

Description from the maker (original English)

Free email checks: 24 blacklists, spoofing grade, redirects, spam test, WHOIS, BIMI, AI readiness.

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

  • Connection: Runs in the cloud
  • Transport: Streamable HTTP
  • Category: Chat & email

Install

Pick the AI app you use, then copy the settings.

Passed 2/3 checks · What you ask goes through the maker’s server (mcp.postboxservices.com)

First: which AI do you use?

Pick your app and the steps appear below.

Works with Claude · about 2 min

No key, nothing to install · Set it up once on claude.ai or the desktop app, then use it in chat · free accounts can add 1

  1. Open Claude’s Connectors page

    CustomizeConnectors

    CustomizeConnectors1+ Add2https://…3Add4
  2. Click “+ Add” → “Add custom connector” and fill in these 2 fields

    Copy each value into the field with the same name in Claude, then click Continue

    Name · NamePostbox Tools
    Remote MCP server URL · Addresshttps://mcp.postboxservices.com/mcp

    Leave Authentication as Claude detected it, then click Add

  3. Turn it on in a chat

    +ConnectorsPostbox Tools

  4. Try it

    Use Postbox Tools and tell me what you can do for me, then show me one thing

    ✓ If Claude says it is using Postbox Tools or shows a Postbox Tools tool in the answer, you are connected

Menu names checked against Anthropic’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with ChatGPT on business plans only

ChatGPT Business, Enterprise or Edu on the web, added by a workspace admin or owner · On Free, Plus or Pro: your ChatGPT plan cannot connect MCP yet

  1. Open ChatGPT’s add-MCP page on the web

    Plugins+Add custom MCP server

    ChatGPTPlugins1+2https://…3Create4
  2. Fill in the name and address

    Enter a name, paste the address under Connection, tick the risk warning and click Create as a plugin

    Name · NamePostbox Tools
    Connection · Addresshttps://mcp.postboxservices.com/mcp
  3. Pick Postbox Tools in a chat

    Start a new chat and pick Postbox Tools from your plugins before typing

  4. Try it

    Use Postbox Tools and tell me what you can do for me, then show me one thing

    ✓ If ChatGPT says it is using Postbox Tools or shows a Postbox Tools tool in the answer, you are connected

Menu names checked against OpenAI’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with Claude Code · about 2 min

No key, nothing to install

  1. Open Terminal

    Mac: press Command+Space and type Terminal · Windows: open PowerShell

  2. Paste this command and press Enter

    claude mcp add --transport http postbox-tools https://mcp.postboxservices.com/mcp
  3. Type /mcp in Claude Code

    You should see Postbox Tools listed as connected

  4. Try it

    Use Postbox Tools and tell me what you can do for me, then show me one thing

    ✓ If Claude Code says it is using Postbox Tools or shows a Postbox Tools tool in the answer, you are connected

Menu names checked against Anthropic’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with Cursor · about 2 min

No key, nothing to install

  1. Click this button to open Cursor

    Open in Cursor

    Cursor asks you to confirm; click Install

  2. Open the AI chat in Cursor in Agent mode

  3. Try it

    Use Postbox Tools and tell me what you can do for me, then show me one thing

    ✓ If Cursor says it is using Postbox Tools or shows a Postbox Tools tool in the answer, you are connected

Menu names checked against Cursor’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with VS Code · about 2 min

No key, nothing to install

  1. Click this button to open VS Code

    Open in VS Code

    VS Code asks you to confirm; click Install

  2. Open the AI chat in VS Code in Agent mode

  3. Try it

    Use Postbox Tools and tell me what you can do for me, then show me one thing

    ✓ If VS Code says it is using Postbox Tools or shows a Postbox Tools tool in the answer, you are connected

Menu names checked against VS Code’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Other apps that use MCP, such as Windsurf, Zed or Gemini CLI, each add servers differently. See how in the app list.

See every app that uses MCP →

Address for apps that connect over the web

Addresshttps://mcp.postboxservices.com/mcp

JSON settings are under “For developers” below

Stuck? Ask people who use Postbox Tools💬 Discussion →
For developers: Terminal commands and JSON settings

Over the web

Claude Code

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

Cursor (~/.cursor/mcp.json)

{
  "mcpServers": {
    "postbox-tools": {
      "url": "https://mcp.postboxservices.com/mcp"
    }
  }
}

VS Code (mcp.json)

{
  "servers": {
    "postbox-tools": {
      "type": "http",
      "url": "https://mcp.postboxservices.com/mcp"
    }
  }
}

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

At a glance

Downloads per weeki
Not on npm/PyPI
Verified domain
✓ postboxservices.com
Licencei
No licence stated
Connection
Runs in the cloud
Transport
streamable-http
Latest versioni
0.2.0
Published to registryi
Nov 6, 2026
Code last changedi
–
Maker
postboxservices.com
Repo
–
Registry status
Active

Which apps can use it

Based on how this server connects and on each app’s own docs, checked Nov 10, 2026.

Connect over the internet in

ClaudeChatGPTGooseLM StudioMsty StudioCherry StudioCursorVS Code + GitHub CopilotVisual StudioWindsurf (Devin Desktop)ZedKiroClineContinueJetBrains AI AssistantClaude CodeCodex CLIGemini CLIOpenCodenodecodeWarpLibreChatOpen WebUIRaycast

All apps, with pros and cons →

Related guides

What it can do

Tool names and descriptions exactly as the server reported them on Nov 11, 2026. The maker wrote them, not us; we show them as plain text.

  • check_blacklist

    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.

  • check_spoofability

    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.

  • trace_redirect

    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

  • create_mailtest

    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

  • get_mailtest_result

    Fetch the score and breakdown of a mail test created with create_mailtest, once the user has sent their email to the disposable address.

  • analyze_eml

    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.

  • get_domain_age

    Get a domain's registration date and age (young domains have weak sending reputation).

  • whois_lookup

    WHOIS summary for a domain: registrar, created/updated/expires dates, nameservers, DNSSEC, status flags.

  • check_bimi

    Check a domain's BIMI setup: looks up the default._bimi TXT record, fetches the logo it points to (l=) and validates the SVG against the BIMI SVG Tiny Portable/Secure profile, and reports whether a certificate (a=, VMC or CMC) is referenced. Does not verify the certificate itself

  • check_ai_discoverability

    Grade how discoverable a website is to AI answer engines (ChatGPT search, Perplexity, Claude, Google AI Overviews, Copilot and others) from its public files: robots.txt access for each major AI crawler (answer-engine vs training), sitemap.xml, plus llms.txt and ai.txt as informat

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 11, 2026

  • ! Caution

    Maker matches the repo

    The registry lists no source repo, so we cannot match the publisher (postboxservices.com) to the code

  • … Not checked yet

    Still maintained

    We have not read this repo from GitHub yet

  • … Not checked yet

    Has a licence

    We have not read this repo from GitHub yet

  • ✓ Pass

    Endpoint responds

    Responded in 415 ms (HTTP 200)

  • – Not applicable

    Sign-in with OAuth

    No sign-in needed

  • ✓ Pass

    No hidden instructions in tool descriptions

    Read 10 tool descriptions and found no hidden instructions to the AI

Discussion

Ask, share a tip or report that it does not work. Sorted by what people marked helpful.

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Posts here are written by users, not the PopNx team.

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User reviews

No reviews yet

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Compared with others in Chat & emaili

  • More stars than 0% of the other 1947 servers in this category
  • Published to the registry more recently than 82% of the other 1947 servers in this category
  • Basic checks equal to or better than 48% of the other 1947 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Postbox Tools safe?

It passed 2 of 3 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs in the maker’s cloud. Connect over the internet with nothing to install, but what you send passes through the maker’s servers.

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.2.0) reached the registry 6 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT Business and above.

What can I use instead?

In the same category: Inbox Zero, Agent-Native Chat, draw.io

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:↓ Downloads per weeki★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

Inbox Zero

Search Gmail and Outlook, save drafts, manage email rules, and view email stats.

by elie222Widely used★ 13KUpdated 41 days ago

Runs in the cloud

Agent-Native Chat

Minimal chat-first app with durable threads, actions, and the app-agent loop

by BuilderIOWidely used★ 7.7K Stars for the whole repoUpdated 2 months ago

Runs in the cloud

draw.io

Create draw.io diagrams in chat from Mermaid or XML, shown live and interactive. 10,000+ shapes.

by jgraphWidely used★ 5.8KUpdated yesterday

Runs in the cloud✓ draw.io

README from the maker

No README found in the repo