Plug in. Done.

One-snippet setup for the runtime your agent already runs in. MCP-native for the agent IDEs, native SDKs for everything else.

Chat and coding agents

  • Claude

    Add mails as a custom connector on claude.ai or Claude Desktop, then use it in any chat.

  • Claude Code

    Add the hosted server with one command and sign in from /mcp in any session.

  • Codex

    Add the server with codex mcp add; the CLI, IDE extension and app share it.

  • Cursor

    Add the server to mcp.json and Cursor’s Agent can send, reply and read threads.

  • GitHub Copilot

    Add mails in VS Code with MCP: Add Server, or give the cloud agent an API key.

  • Gemini

    Add it with gemini mcp add and sign in with /mcp auth; Code Assist reads it too.

  • Windsurf

    Add the server to mcp_config.json in Windsurf, now Devin Desktop, for Cascade.

  • Cline

    Add the server in the MCP Servers panel; with auto-approve off, Cline asks first.

  • Continue

    Add the server to config.yaml and use it in Agent mode in VS Code or JetBrains.

Apps built from a prompt

  • Lovable

    Connect mails as an MCP server while you build; your app keeps its key in secrets.

  • Replit

    Add the server once under Integrations and Replit Agent uses it in every project.

  • v0

    Pick MCPs in v0’s + menu to use mails while it builds; your app reads its key from env.

  • Bolt

    Add a custom connector, turn it on per project, and keep the API key in secrets.

Agent frameworks

  • OpenAI Agents SDK

    Attach the MCP server to an agent, or wrap the SDK in function tools you control.

  • Anthropic SDK

    Let Claude’s API call the hosted server through the MCP connector, or use the SDK.

  • Vercel AI SDK

    Load the server’s tools with createMCPClient, or wrap the SDK in tool() calls.

  • LangGraph

    Wrap the Python SDK as tools and bind them to any node in a StateGraph.

  • Pydantic AI

    Give a typed Python agent tools to send and read mail, or load the MCP server.

One command

Add the server from your terminal

The CLI connects Claude, Claude Code, Cursor, Codex or VS Code to the hosted MCP server, and you sign in through your browser. Any file it changes is copied to a backup first.

npx @mailsai/cli mcp install --client claude-code

How guides connect

Three ways to connect

Every guide uses one of three: the hosted MCP server, an SDK, or the REST API with a key.

  • Hosted MCP

    Chat and coding agents add https://api.mails.ai/mcp and sign in. Nothing runs on your machine.

  • SDKs

    Agent frameworks call the TypeScript or Python SDK from tools you define, with an API key.

  • REST API

    Apps built from a prompt call the API themselves, with a key kept in the builder’s secrets.

Frequently asked questions

Which tools have a setup guide?
Chat and coding agents: Claude, Claude Code, Codex, Cursor, GitHub Copilot, Gemini, Windsurf, Cline and Continue. Apps built from a prompt: Lovable, Replit, v0 and Bolt. Agent frameworks: OpenAI Agents SDK, Anthropic SDK, Vercel AI SDK, LangGraph and Pydantic AI.
My tool is not listed. Can I still connect it?
Yes. Any MCP client can use the hosted server at https://api.mails.ai/mcp, and anything that can make an HTTP request can call the REST API. Every way in is on one page: Connect any agent.
Do I need an API key?
Not for the hosted MCP server: you sign in with your mails.ai account. A client that cannot sign in can send an API key as a Bearer header instead, and the SDKs and the REST API always use a key.
What is the difference between the MCP server and the SDKs?
The MCP server gives a tool-calling client ready-made email tools. The TypeScript and Python SDKs are for code you write: your app, or the tools you define in an agent framework, call them.
Can I add the MCP server from my terminal?
Yes. mails mcp install --client claude-code adds the hosted server to Claude Code, and the same command knows Claude, Cursor, Codex and VS Code. Any file it changes is copied to a backup first, and --print shows what it would do without changing anything.
Can apps I build in Lovable, Replit, v0 or Bolt send email?
Yes. Each builder can use the MCP server while it builds, and the app itself calls the REST API with an API key kept in that builder’s secrets or environment variables. Each guide shows where that setting lives.
Can my agent read the replies it gets?
Yes. Replies arrive on the agent’s own address with the quoted history stripped, an injection score and the sender’s reputation. Read them over MCP with mails_list_replies, through the API, or have each one pushed to your webhook.
What can’t an app connected over MCP do?
An app you connect by signing in cannot create API keys or webhooks and cannot open billing. It can read your usage. Keys and webhooks stay with you in the dashboard.
Is mails.ai free to try?
Yes. The Free plan covers 3,000 emails and 3,000 inbound replies a month with no card. Paid plans add more volume when your agents get busy.

“Replies come back as events with an injection score already on them. We deleted a whole layer of parsing code the week we switched, and we gate on the quarantine flag, so our agent never sees the ones that look like attacks.”

Tomás VargaStaff Engineer, Cinderjay

“Moving our agent onto our own domain was a few DNS records at the registrar. No nameserver move, and our existing mail kept working. Replies to the agent still come back to its inbox, threaded with the message they answer.”

Ishani VaidyaCTO, Sedgequay

“The 422 on cold outreach is the feature I didn’t know I wanted. An agent can’t talk itself into emailing strangers.”

Marcus FeldFounder, Marrowkite

“Our tests send to the test address and wait for the real reply, so the whole loop is covered before a customer ever writes in. It answers in about a second, which keeps the suite fast.”

Ana Lucía RíosEngineering Lead, Gorsefinch

“Adding the MCP server was one JSON block. Claude Code could send and read its own inbox a minute later.”

Jonah AbramsDeveloper, Wickerjay

“A reputation score per agent tells us exactly which one needs attention, instead of one number for the whole account. It comes from each agent’s own replies, bounces and complaints, and we read it from the API.”

Mei Lin ZhouOperations, Larchwhistle

“Sends and replies have separate allowances, so a busy inbox never eats our sending quota. Pricing was the easy part.”

Kwabena AdomakoFounder, Oxbowlark

“Half our agents are LangGraph in Python and half are Node. Both SDKs make the same calls, so the team doesn’t have to think about it.”

Sofia BrandtEngineer, Moss & Ladder

“Signed webhooks, retries with backoff and an event id to dedupe on. The boring plumbing, done properly.”

Nikhil BhonsleBackend Lead, Thimblecrow

“We signed up, made a key and sent our first message without talking to anyone, and the free tier never asked for a card. That’s how infrastructure should feel.”

Frieda WesselFounder, Ploverwick Studio

Give your first agent an inbox

Free covers 3,000 emails and 3,000 inbound replies a month, with no card. Upgrade when your agents get busy.

Get your API key