Mcp Email Rs

mcp-email-rs

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Enterprise-grade MCP email server in pure Rust. Gives any MCP client (Claude Code, Codex, or anything speaking MCP over stdio) full IMAP access and SMTP sending — read, search, organize, draft, and send mail with your own account, no third-party service in the middle.

The server talks IMAP/SMTP directly to your provider over TLS. Credentials stay in your environment (or a local config file); they are never persisted or logged by the server and never leave your machine except to your own mail provider.

Why

Agents that can read and send email are far more useful, but most integrations route your mailbox through a vendor's cloud. This server keeps the connection direct: your IMAP/SMTP host, your credentials, your machine. Swap the model or the MCP client — the same mailbox tools are there, and nothing about your mail is mediated by a platform.

Design choices that follow from that:

• Direct IMAP/SMTP: TLS connections straight to your provider (rustls); no

proxy, no account on someone else's service.

• Credentials from the environment: read from env vars or a local

email.toml/.env; both are git-ignored and never logged.

• Pooled & resilient: connection pooling (bb8), non-blocking pool creation,

cached SMTP transport, folder-name resolution (incl. localized Gmail folders).

• Auth options: PLAIN, LOGIN, XOAUTH2 (caller-supplied token), CRAM-MD5.
• Read-only by intent: read/search tools are annotated readOnlyHint, so an

MCP approval gate can auto-allow them while still gating mutations and sends.

> The family: for curated agent state (versioned JSON categories, fleet > sync) see mcp-memory-rs; for > corpus recall (chunked documents, BM25 retrieval) see > mcp-vl-msa-rs. This server adds > the mailbox.

Install

Prebuilt binary (recommended) — download the archive for your platform from the latest release, extract, and point your MCP client at the binary:

tar xzf mcp-email-rs-x86_64-unknown-linux-gnu.tar.gz
install -m755 mcp-email-rs-*/mcp-email-rs ~/.local/bin/

Prebuilt targets (Linux + Android): x86_64-unknown-linux-gnu, x86_64-unknown-linux-musl, aarch64-unknown-linux-gnu, aarch64-unknown-linux-musl (edge / ARM / Termux), aarch64-linux-android.

macOS: no prebuilt binary is shipped (it would need Apple code-signing). Install from source instead:

cargo install --git https://github.com/DioNanos/mcp-email-rs --locked

--locked uses the committed Cargo.lock (reproducible build).

Quick start

cargo build --release
./target/release/mcp-email-rs   # stdio MCP server

Claude Code (~/.claude.json) or any MCP client:

{
  "mcpServers": {
    "email": {
      "command": "/path/to/mcp-email-rs",
      "env": {
        "IMAP_HOST": "imap.example.com",
        "IMAP_USER": "you@example.com",
        "IMAP_PASSWORD": "your-app-password"
      }
    }
  }
}

Codex (~/.codex/config.toml):

[mcp_servers.email]
command = "/path/to/mcp-email-rs"
env = { IMAP_HOST = "imap.example.com", IMAP_USER = "you@example.com", IMAP_PASSWORD = "..." }
# auto-approve read-only tools (list/get/search/…); mutations and sends still gated
default_tools_approval_mode = "approve"

Configuration

Credentials are read from environment variables (or a local email.toml). Copy .env.example to .env and fill in your values:

IMAP_HOST=imap.example.com
IMAP_PORT=993
IMAP_USER=you@example.com
IMAP_PASSWORD=your-app-password
IMAP_TLS=true
IMAP_AUTH=plain            # plain | login | xoauth2 | cram-md5

# SMTP is optional — defaults to the IMAP host/credentials
# SMTP_HOST=smtp.example.com
# SMTP_PORT=587

For Gmail/Workspace use an app password (or XOAUTH2). A email.toml file is also supported — see email.toml.example. Run the built-in email_doctor tool for a safe, machine-readable diagnostic of your configuration.

Tool surface

| Area | Tools | |---|---| | Read | list_emails, list_emails_with_headers, get_email, get_email_raw, search_emails, get_bodystructure, download_attachment | | Folders | list_folders, create_folder, delete_folder, rename_folder, list_namespaces | | Organize | move_email, move_thread, copy_email, delete_email, batch_delete, flag_email, mark_seen, batch_mark_seen | | Drafts & send | create_draft, update_draft, list_drafts, send_email | | Ops | get_quota, email_doctor, idle_wait |

Read tools carry a readOnlyHint; mutations and send_email are intended to pass through your client's approval gate.

Security

• Credentials are taken from the environment or a local config file and are

never persisted or logged by the server.

• .env, .env.local, email.toml, and tokens/ are git-ignored — keep your

real credentials out of version control.

• All IMAP/SMTP traffic uses TLS (rustls).

Building and testing

cargo build --release
cargo test --all-targets
cargo clippy --all-targets -- -D warnings

License

Apache-2.0. See [LICENSE](LICENSE).

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: DioNanos
• Source: DioNanos/mcp-email-rs
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.