Claws Mail Plugin MCP server

claws-mail-mcp-plugin

Native Claws Mail plugin that exposes the running mail client as an MCP server.

It runs inside Claws Mail and serves a local, loopback-only HTTP endpoint (JSON-RPC over MCP, bearer-token protected). Any MCP-capable AI tool can then read folders and messages, search, compose, reply, forward, manage folders and flags, and send or receive mail through your already-configured accounts. Endpoint, port, token and read-only mode are set in mcppluginrc inside the Claws Mail config directory; the plugin writes a ready-to-paste client config to mcpclient.json in the same place on every start.

Installing the plugin

Prebuilt binaries are attached to each release, one per OS and supported Claws Mail version (e.g. mcpplugin-linux-claws4.3.1.so, mcpplugin-windows-claws4.3.0.dll). Pick the file matching your Claws Mail version and OS, then:

1. Copy it into your Claws Mail plugin directory (pkg-config --variable=plugindir claws-mail, typically ~/.claws-mail/plugins or %APPDATA%\Claws-mail\plugins on Windows).
2. Restart Claws Mail.
3. Enable it under Configuration > Plugins if it is not loaded automatically.

To build from source instead, see Building.

Connecting an AI tool

Once loaded, the plugin writes the real endpoint URL and bearer token to mcp_client.json in the Claws Mail config directory. Use those two values with whichever method below matches your tool. The server is loopback-only (127.0.0.1), so it is reachable only from AI tools running on the same machine as Claws Mail.

Claude Code

claude mcp add --transport http claws-mail http://127.0.0.1:8765/mcp \
  --header "Authorization: Bearer <TOKEN>"

Claude Desktop

Settings > Developer > Edit Config, then merge in packaging/claude/mcp.json (fill in ). Do not use the "Add custom connector" UI for this server: that flow connects from Anthropic's servers, not from your machine, so it cannot reach a loopback address.

VS Code / GitHub Copilot Chat

code --add-mcp "{\"name\":\"claws-mail\",\"type\":\"http\",\"url\":\"http://127.0.0.1:8765/mcp\",\"headers\":{\"Authorization\":\"Bearer <TOKEN>\"}}"

Or copy packaging/vscode/mcp.json to .vscode/mcp.json; it prompts for the token instead of storing it in the file.

Codex CLI

export CLAWS_MCP_TOKEN=<TOKEN>
codex mcp add claws-mail --url http://127.0.0.1:8765/mcp --bearer-token-env-var CLAWS_MCP_TOKEN

This matches packaging/codex/config.toml, which Codex reads from ~/.codex/config.toml.

MCP registry

packaging/registry/server.json is published to the MCP registry as io.github.it-atelier-gn/claws-mail-mcp-plugin on every tagged release, via .github/workflows/ci.yml's publish-registry job (GitHub OIDC auth, no stored credentials). The registry rejects loopback URLs as remotes, so this is a discovery-only listing without connection details; it links back to this README for installation and the per-tool commands above.

Building

Requires Meson, Ninja, a C compiler, and the Claws Mail development files (GTK3, GLib, GnuTLS, libgcrypt, enchant).

Linux

Install dependencies (Debian/Ubuntu example):

sudo apt-get install build-essential meson ninja-build pkg-config \
  libgtk-3-dev libglib2.0-dev libgnutls28-dev libgcrypt20-dev libenchant-2-dev

If a claws-mail pkg-config file is not already on your system, build one with:

Shortened. The full README is on GitHub.