sendmux-mcp

Curated Model Context Protocol servers for the Sendmux Mailbox, Management, and Sending API surfaces.

This package is the Sendmux product MCP. Keep it separate from any documentation-search MCP used by docs tooling.

Documentation

• Sendmux docs: sendmux.ai/docs

• Management API reference: sendmux.ai/docs/api/introduction

• Mailbox API reference: sendmux.ai/docs/mailbox-api/introduction

• Sending API reference: sendmux.ai/docs/sending-api/introduction

• Source repository: Sendmux/sendmux-sdk

Related MCP server: mcp-server-lobstermail

Requirements

• Python 3.10 or newer.

• A mailbox-scoped smx_mbx_* key for Mailbox and Sending tools.

• A root smx_root_* key for Management tools.

Installation

pip install sendmux-mcp

Usage

Run a single local server with the per-surface commands.

SENDMUX_API_KEY=smx_mbx_... sendmux-mcp-mailbox
SENDMUX_API_KEY=smx_root_... sendmux-mcp-management
SENDMUX_API_KEY=smx_mbx_... sendmux-mcp-sending

Run a combined local server with sendmux-mcp.

SENDMUX_MCP_SURFACES=mailbox,sending \
SENDMUX_MAILBOX_API_KEY=smx_mbx_... \
SENDMUX_SENDING_API_KEY=smx_mbx_... \
sendmux-mcp

Run all three local surfaces when you have both key types.

SENDMUX_MCP_SURFACES=mailbox,management,sending \
SENDMUX_MAILBOX_API_KEY=smx_mbx_... \
SENDMUX_MANAGEMENT_API_KEY=smx_root_... \
SENDMUX_SENDING_API_KEY=smx_mbx_... \
sendmux-mcp

The generic sendmux-mcp command also accepts --surface or --surfaces. The wrapper commands select exactly one surface.

Transports

stdio is the default transport for local agent clients.

SENDMUX_API_KEY=smx_mbx_... sendmux-mcp-mailbox --transport stdio

http and streamable-http expose the MCP endpoint over HTTP. HTTP mode defaults to 127.0.0.1:8765/mcp and requires a separate MCP bearer token unless you explicitly opt out.

SENDMUX_API_KEY=smx_mbx_... \
SENDMUX_MCP_HTTP_BEARER_TOKEN=local-mcp-token \
sendmux-mcp-mailbox --transport http --host 127.0.0.1 --port 8765 --path /mcp

/health returns a small JSON health response for the selected surfaces.

Hosted Endpoint

The public hosted MCP endpoint is https://mcp.sendmux.ai/mcp.

The packaged sendmux-mcp-hosted command runs the hosted server runtime. Local and private deployments should use the local commands above unless you are operating a compatible OAuth-backed hosted environment.

Configuration

Packaged OpenAPI snapshots are the default so released tool names, schemas, and descriptions stay stable. Path, directory, and URL overrides are available for development, canary, and debugging runs.

Tool Surfaces

• Mailbox: 21 tools for granted mailboxes, profile/session discovery, messages, threads, folders, search, counts, and mailbox sends. Requires an smx_mbx_* key.

• Management: 20 tools for domains, mailboxes, logs, metrics, spend summary, and webhooks. Requires an smx_root_* key.

• Sending: 2 tools for single and batch sends. Requires an smx_mbx_* key.

The server rejects keys with the wrong prefix before starting.

Console Scripts

• sendmux-mcp

• sendmux-mcp-mailbox

• sendmux-mcp-management

• sendmux-mcp-sending

• sendmux-mcp-hosted

Support

Open an issue in Sendmux/sendmux-sdk with the package name, version, command, transport, and request ID from any API error.

Licence

MIT. See the licence file.