Mailsnail

Name: Mailsnail
Author: iancollins27

作者：iancollins27版本 0.6.0i★ –i在你的电脑上运行

注册名称io.github.iancollins27/mailsnail

安装

概览

作者提供的说明（英文原文）

Send USPS letters, postcards & certified mail from any agent. No signup; pay-per-piece via Stripe.

PopNx MCP 的三大支柱

这三项永远不会合并成一个分数：意见、测量和人气是不同的东西。

用户评价i暂无评价评价功能将在后续阶段与账户功能一起开放
我们的基础检查i1 项中通过 1 项依据公开信息检查；尚未扫描代码
使用情况i尚未统计★ –

它能帮你做什么

我们还没有为它写通俗的介绍。下面是我们从注册中心读取到的事实。

连接方式: 在你的电脑上运行
传输方式: stdio
分类: 网店与支付
你需要填写：MAIL_PROVIDER, CLICK2MAIL_PASSWORD, LOB_API_KEY

安装

选择你使用的 AI 应用，然后复制设置。

安装之前

基础检查：1 项中通过 1 项
在你的电脑上运行，拥有你的用户账户的权限（文件、网络、应用）。
需要你自己填写： MAIL_PROVIDER, MAIL_API_BASE_URL, CLICK2MAIL_USERNAME, CLICK2MAIL_PASSWORD, LOB_API_KEY, MAIL_MCP_ALLOW_LIVE, MAIL_MCP_SPEND_CAP_USD

标为机密的值是你账户的钥匙。千万不要分享给别人，也不要粘贴到聊天里。

你需要

npm已安装 Node.js（用于 npx 命令）

你用的是哪个应用？

ClaudeClaude CodeCursorVS CodeChatGPT

在上方选择你的应用。我们会记住它，下次按钮会显示“安装到 …”。

打开 Claude Desktop → Settings → Developer → Edit Config，把下面的内容粘贴到 claude_desktop_config.json

{
  "mcpServers": {
    "mailsnail": {
      "command": "npx",
      "args": [
        "-y",
        "mailsnail"
      ],
      "env": {
        "MAIL_PROVIDER": "your-value",
        "MAIL_API_BASE_URL": "your-value",
        "CLICK2MAIL_USERNAME": "your-value",
        "CLICK2MAIL_PASSWORD": "your-value",
        "LOB_API_KEY": "your-value",
        "MAIL_MCP_ALLOW_LIVE": "your-value",
        "MAIL_MCP_SPEND_CAP_USD": "your-value"
      }
    }
  }
}

在终端中运行这条命令

claude mcp add mailsnail --env MAIL_PROVIDER=your-value --env MAIL_API_BASE_URL=your-value --env CLICK2MAIL_USERNAME=your-value --env CLICK2MAIL_PASSWORD=your-value --env LOB_API_KEY=your-value --env MAIL_MCP_ALLOW_LIVE=your-value --env MAIL_MCP_SPEND_CAP_USD=your-value -- npx -y mailsnail

运行前请先填写空着的值。

在 Cursor 中打开

或者自己复制设置

粘贴到项目中的 .cursor/mcp.json，或 ~/.cursor/mcp.json

{
  "mcpServers": {
    "mailsnail": {
      "command": "npx",
      "args": [
        "-y",
        "mailsnail"
      ],
      "env": {
        "MAIL_PROVIDER": "your-value",
        "MAIL_API_BASE_URL": "your-value",
        "CLICK2MAIL_USERNAME": "your-value",
        "CLICK2MAIL_PASSWORD": "your-value",
        "LOB_API_KEY": "your-value",
        "MAIL_MCP_ALLOW_LIVE": "your-value",
        "MAIL_MCP_SPEND_CAP_USD": "your-value"
      }
    }
  }
}

浏览器会先询问是否打开应用，然后应用会显示设置并请你确认。密钥的值会留空，由你自己填写。

在 VS Code 中打开

或者自己复制设置

粘贴到项目中的 .vscode/mcp.json

{
  "servers": {
    "mailsnail": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "mailsnail"
      ],
      "env": {
        "MAIL_PROVIDER": "your-value",
        "MAIL_API_BASE_URL": "your-value",
        "CLICK2MAIL_USERNAME": "your-value",
        "CLICK2MAIL_PASSWORD": "your-value",
        "LOB_API_KEY": "your-value",
        "MAIL_MCP_ALLOW_LIVE": "your-value",
        "MAIL_MCP_SPEND_CAP_USD": "your-value"
      }
    }
  }
}

浏览器会先询问是否打开应用，然后应用会显示设置并请你确认。密钥的值会留空，由你自己填写。

这个服务器在你的电脑上运行，而 ChatGPT 只能连接互联网上的服务器。请选择其他应用。

你的选择通过 Cookie 保存在这台设备上，无需账户。

需要你填写的值

MAIL_PROVIDER 必填 env
Where to mail from: 'managed' (default, no signup, pay-per-piece via Stripe), 'click2mail' (BYO account), or 'lob' (BYO key).
MAIL_API_BASE_URL env
Hosted Mailsnail backend. Required when MAIL_PROVIDER=managed.
CLICK2MAIL_USERNAME env
Click2Mail account username. Required when MAIL_PROVIDER=click2mail.
CLICK2MAIL_PASSWORD 机密 env
Click2Mail account password. Required when MAIL_PROVIDER=click2mail.
LOB_API_KEY 机密 env
Lob API key. Required when MAIL_PROVIDER=lob. test_* is free; live_* actually mails.
MAIL_MCP_ALLOW_LIVE env
Set to '1' to actually mail in BYOK modes. Default '0' is dry-run.
MAIL_MCP_SPEND_CAP_USD env
Per-session estimated spend cap. Server refuses sends past this.

这些设置是根据作者在注册中心的条目生成的。如果 README 的写法不同，请以 README 为准。

它能做什么

它在你的电脑上运行；安装后，工具列表会显示在你的 AI 应用中。

基础检查i

我们检查的是任何人都能看到的信息；我们没有阅读代码。不适用的检查项不计入总数。 · 检查于 2026年11月7日

✓ 通过
作者与仓库一致
注册名称已通过 GitHub 账户 iancollins27 验证，该账户拥有此仓库
… 尚未检查
仍在维护
我们还没有从 GitHub 读取这个仓库
… 尚未检查
有许可证
我们还没有从 GitHub 读取这个仓库
– 不适用
端点有响应
它在你的电脑上运行，没有互联网端点
– 不适用
使用 OAuth 登录
在你的电脑上运行，改用本地设置
… 尚未检查
工具描述中没有隐藏指令
它在你的电脑上运行；我们只能读取互联网端点的工具列表

与“网店与支付”中的其他服务器比较i

星标数多于此分类中其他 1752 个服务器的 0%
发布到注册中心的时间比此分类中其他 1752 个服务器的 21% 更新
基础检查结果等于或优于此分类中其他 1752 个服务器的 100%

与注册中心里这个分类中所有活跃的服务器比较。只有当发布者拥有该仓库时，星标数才计入。

常见问题

Mailsnail 安全吗？

它在 1 项适用的基础检查中通过了 1 项。我们没有阅读代码。在添加密钥或令牌之前，请先看看这个服务器要求哪些权限，并使用只具备所需权限的密钥。

它需要哪些密钥或代码？

你需要填写：MAIL_PROVIDER, CLICK2MAIL_PASSWORD, LOB_API_KEY

它在我的电脑上运行还是在云端？

它在你的电脑上运行。你的 AI 应用会在需要时启动它，数据不会经过作者的服务器（除非它自己调用在线服务）。

它还在维护吗？

GitHub 仓库最后更新于–，最新版本（0.6.0）于4个月前进入注册中心。

哪些应用可以使用它？

支持 MCP 的应用，例如 Claude Desktop、Claude Code、Cursor 和 VS Code。你的电脑上还需要有 Node.js。

有什么可以替代它？

同一分类中有：Spree Commerce: open-source B2B and marketplace ecommerce, Stripe MCP, MCP Cn Commerce

替代选择

同一分类中其他作者的服务器，按星标数排序。

如何看卡片：★ GitHub 星标i三大支柱：评价 · 检查 · 使用情况i更新 = 最新版本发布到注册中心的时间i

Spree Commerce: open-source B2B and marketplace ecommerce

作者：spree

Open-source B2B and marketplace ecommerce; new stores include an MCP server for AI agents.

在云端运行★ 15,812BSD-3-Clause7天前更新

安装

Stripe MCP

作者：stripe

MCP server integrating with Stripe - tools for customers, products, payments, and more.

在云端运行★ 2,043MIT12个月前更新

安装

MCP Cn Commerce

作者：TonyWang-hub

8 read-only MCP platform entries; support is operation-specific; merchant live acceptance pending

在你的电脑上运行★ 96MIT28天前更新

安装

作者的 README

打开 README

按原文从作者的仓库复制。PopNx MCP 没有审查或背书其内容。HTML、图片和脚本已被移除。链接会离开本站。

Mailsnail

Open-source, provider-agnostic physical mail for AI agents.

Agents have every channel except one. They can email, text, call, and post to every feed — but until now, putting a real, postmarked envelope in a mailbox meant a human signing up for a print-provider account, provisioning API keys, and wiring billing. Mailsnail closes that gap:

Nothing to install. Add one URL to Claude, ChatGPT, Cursor or any MCP client and sign in. Pay for one letter by card or fund a balance, priced at our cost: from $1.21 first-class and $8.61 certified, no subscription. Agents that can mint a Stripe Shared Payment Token can also pay per piece with no account, over the Machine Payments Protocol (HTTP 402).
No lock-in, ever. The provider layer is open and swappable: bring your own Click2Mail or Lob account, self-host the whole gateway, or chain providers for failover. The managed service is a convenience, not a cage.
Built for compliance mail. Certified letters with extra_service: "certified" — the mail that legally *must* be physical (preliminary lien notices, legal notices) and must not miss its deadline because one print API had a bad day.

claude mcp add -t http mailsnail https://api.mailsnail.dev/mcp

then /mcp → mailsnail → Authenticate, and: "Mail a thank-you letter to my aunt."

In Claude Desktop or ChatGPT, add https://api.mailsnail.dev/mcp as a custom connector. Steps for every app: mailsnail.dev/setup. Running your own Click2Mail or Lob account instead? See Ways to run it.

Hosted connector and plugins

The quickest start needs no install. Add https://api.mailsnail.dev/mcp as a custom connector in Claude, ChatGPT, Cursor or any MCP client that supports remote servers, then sign in. Each app's setup steps are at mailsnail.dev/setup.

plugins/mailsnail packages that connector with skills for sending letters, sending certified mail and tracking mail. It works in Claude (chat, Cowork and Claude Code) and in Cursor. To install it in Claude Code:

/plugin marketplace add iancollins27/mailsnail

/plugin install mailsnail@mailsnail

Packages

Package	What it is
`mailsnail`	MCP server — 11 tools (`doctor`, `verify_address`, `preview_letter`, `send_letter`, `send_postcard`, `get_balance`, `top_up`, `get_letter`, `get_postcard`, `list_letters`, `cancel_letter`) over any provider below. Works in Claude Code, Claude Desktop, Cursor, Codex CLI, OpenAI Agents SDK.
`@mailsnail/core`	Provider-agnostic core: adapters (Click2Mail, Lob, any Mailsnail gateway), multi-provider failover router, request validation. Zero dependencies.
`@mailsnail/gateway`	Self-hostable REST API: BYO provider credentials, `body_text`→PDF rendering, proofs, invocation logging. The managed service at `api.mailsnail.dev` runs the same wire protocol.
`spec/`	The provider-neutral mail-piece schema + the failover-safety contract. Implement it and anything — including a print shop — becomes a Mailsnail-compatible node.

Ways to run it

Mode	Credentials	Paying	Good for
hosted connector (`api.mailsnail.dev/mcp`)	none; you sign in	you, per letter by card or from a balance	people in Claude, ChatGPT, Cursor; zero-setup
managed (stdio default)	none	agent, per piece (Stripe SPT)	agents that can mint an SPT
gateway	your own, on your server	your provider account	teams; PII stays in your infra
click2mail / lob (BYOK)	yours, local env	your provider account	direct control, one provider
failover chain	yours, per provider	your provider accounts	mail that must not miss deadlines

Failover is deliberately conservative: a send moves to the next provider only when the failed provider guarantees nothing entered production and no money moved (safeToRetry — see the spec). A duplicate certified letter is worse than an error.

Running behind an egress proxy or allowlist

Sandboxed agents — CI runners, enterprise agent platforms, hosted agent sessions — usually sit behind an egress allowlist, and that is the environment managed mode is *for*. Two minutes of setup:

npx mailsnail doctor      # says exactly what it can and can't reach, and why. Free; never mails.

Allow this host:

Mode	Host to permit	Port
managed (default)	`api.mailsnail.dev`	443 (TCP / HTTPS `CONNECT`)
self-hosted gateway	whatever `MAIL_API_BASE_URL` points at	its port
click2mail (BYOK)	`rest.click2mail.com`	443
lob (BYOK)	`api.lob.com`	443

Allowlist by hostname, not IP: the managed gateway runs on managed infrastructure and its addresses change without notice. If your policy is IP-only, self-host @mailsnail/gateway on an address you control — that escape hatch is the whole point of the open provider layer.

Through an HTTP proxy. Node's fetch ignores HTTPS_PROXY unless you tell it not to, so an allowlisted gateway can still time out silently. Either:

export NODE_USE_ENV_PROXY=1        # Node >= 22.21

export HTTPS_PROXY=http://proxy.example:8080

or install undici alongside mailsnail (npm i undici) and Mailsnail routes through HTTPS_PROXY/HTTP_PROXY/ALL_PROXY itself, honoring NO_PROXY. mailsnail doctor tells you which of these is actually in effect.

TLS-inspecting proxy? Point NODE_EXTRA_CA_CERTS at your organization's CA bundle.

When it's blocked anyway, the failure says so instead of guessing: transport errors carry a code of unreachable, egress_blocked, or tls_untrusted, plus the exact host:port to permit. Any of those codes means the request never reached the backend — nothing mailed, nothing was charged, and the fix is network policy, not your account.

Safety

Dry-run by default everywhere; live mail requires an explicit MAIL_MCP_ALLOW_LIVE=1.
Per-session spend caps in the MCP server; auto-refund in managed mode when a paid piece fails to mail.
preview_letter returns a proof PDF and exact price before anything is charged — show it to your user first.
Don't use this for spam, harassment, or fraud. Provider terms and USPS regulations apply; managed mode enforces its own abuse screening.

Why open source

You're letting software put paper in mailboxes and spend money doing it. Read the code. Run it yourself with your own provider account for free. Use managed mode when you'd rather not hold credentials at all. If we ever disappoint you, MAIL_PROVIDER=click2mail and your mail keeps moving — that's the deal, and it's enforceable because this repo exists.

Status

Early. US-only today. Letters, certified letters, and postcards. The managed API, MCP server, self-host gateway, and Click2Mail/Lob adapters are live; additional adapters (PostGrid, Stannp) are next — CONTRIBUTING.md has the adapter guide if you want one sooner.

License

MIT.

Mailsnail

概览

PopNx MCP 的三大支柱

它能帮你做什么

安装

安装之前

需要你填写的值

它能做什么

基础检查i

作者与仓库一致

仍在维护

有许可证

端点有响应

使用 OAuth 登录

工具描述中没有隐藏指令

与“网店与支付”中的其他服务器比较i

常见问题

替代选择

Spree Commerce: open-source B2B and marketplace ecommerce

Stripe MCP

MCP Cn Commerce

作者的 README

Mailsnail

then /mcp → mailsnail → Authenticate, and: "Mail a thank-you letter to my aunt."

Hosted connector and plugins

Packages

Ways to run it

Running behind an egress proxy or allowlist

Safety

Why open source

Status

License