Koskamo

Plainmail MCP

An official MCP server provided by Plainmail that allows AI agents to manage email hosting infrastructure and communications. It enables setting up domains, configuring DNS records, creating mailboxes, and reading, sending, and replying to emails via IMAP/SMTP integration.

Visit Plainmail

Endpoint and access

OAuth sign-in: the first time you connect, your client opens the vendor's own authorization prompt in a browser.

Plainmail MCP logo, by PlainmailVendor evidenceStreamable HTTPOAuth sign-inEndpoint checked 2026-11-06Operated by Plainmail
You need:You need a Plainmail account with an active subscription.create an API key in Settings and send it as a header: Authorization: Bearer <key> .
MCP endpoint (Streamable HTTP)
https://app.plainmail.dev/api/mcp/mcp
Vendor documentation

Checks and signals

Each line is separate evidence, not a trust score.

  • Passed Endpoint answered the live check ·
  • Passed Official MCP Registry namespace is tied to plainmail.dev ·
  • Passed Endpoint is on the registry namespace domain ·
  • Availability 1 of 1 checks passed in 30 days

What you can do with it

  • Set up a new domain and configure its mail DNS records
  • Create and manage email mailboxes and aliases
  • Read and list incoming email messages
  • Send and reply to emails from configured addresses

Source and maintenance

Vendor evidenceRegistry 1.1.0
mcp-registry: dev.plainmail/mail@1.1.0Project website

Tools

Reported by the attributed source; not independently observed by Koskamo.

No tool definitions available.

90-day uptime

A lightweight connection check about every six hours, sampled on hosts with many listings. It shows the server answered, not that its tools work.

Too few checks for a percentage yet (2 of 2 answered).

  1. 2026-11-07: 2 of 2 checks answered

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks
1 of 1 (100%)
Average latency
106 ms
95th percentile latency
106 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

  • · probe · passed · 106 ms · metadata changed · refuses unauthenticated initialize (HTTP 401)

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.
Claude Code configuration
claude mcp add --transport http plainmail-mcp https://app.plainmail.dev/api/mcp/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).
Codex configuration
codex mcp add plainmail-mcp --url https://app.plainmail.dev/api/mcp/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable plainmail-mcp in your MCP settings.
Cursor configuration
{
  "mcpServers": {
    "plainmail-mcp": {
      "url": "https://app.plainmail.dev/api/mcp/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).
Cline configuration
{
  "mcpServers": {
    "plainmail-mcp": {
      "type": "streamableHttp",
      "url": "https://app.plainmail.dev/api/mcp/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start plainmail-mcp and inspect its tools.
VS Code configuration
{
  "servers": {
    "plainmail-mcp": {
      "type": "http",
      "url": "https://app.plainmail.dev/api/mcp/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.
Gemini CLI configuration
gemini mcp add --transport http plainmail-mcp https://app.plainmail.dev/api/mcp/mcp

Claude Desktop

Open Claude Settings > Connectors > Add custom connector, enter this server URL and enable it for the conversation. This is a manual remote-connector handoff, not a desktop JSON configuration.
Claude Desktop configuration
https://app.plainmail.dev/api/mcp/mcp

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.
Windsurf configuration
{
  "mcpServers": {
    "plainmail-mcp": {
      "serverUrl": "https://app.plainmail.dev/api/mcp/mcp"
    }
  }
}

Let your agent find its tools

Find servers like Plainmail MCP from your agent. Add Koskamo once to search the index for endpoints, access requirements, and client setup. Public discovery needs no key.

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Do you run Plainmail MCP?

Prove ownership with a DNS record, a well-known file, or your Official MCP Registry entry, and your edits publish immediately. Proofs are re-checked weekly; admins can still hide or remove a listing.

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