sendmux-mcp 1.1.3

Curated MCP servers for the Sendmux API surfaces.

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

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

Setting	Environment	Default
Tool surfaces	SENDMUX_MCP_SURFACES	required for sendmux-mcp; wrapper commands select one surface
API key fallback	SENDMUX_API_KEY	accepted for compatible single-key setups
Mailbox API key	SENDMUX_MAILBOX_API_KEY	required when mailbox is selected unless a compatible fallback is provided
Management API key	SENDMUX_MANAGEMENT_API_KEY	required when management is selected unless a compatible fallback is provided
Sending API key	SENDMUX_SENDING_API_KEY	required when sending is selected unless a compatible mailbox key is provided
App API base URL	SENDMUX_APP_BASE_URL	https://app.sendmux.ai/api/v1
Sending API base URL	SENDMUX_SENDING_BASE_URL	https://smtp.sendmux.ai/api/v1
Transport	SENDMUX_MCP_TRANSPORT	stdio
HTTP host	SENDMUX_MCP_HOST	127.0.0.1
HTTP port	SENDMUX_MCP_PORT	8765
HTTP path	SENDMUX_MCP_PATH	/mcp
HTTP bearer token	SENDMUX_MCP_HTTP_BEARER_TOKEN	required for HTTP unless opt-out is enabled
Allow unauthenticated HTTP	SENDMUX_MCP_ALLOW_UNAUTHENTICATED_HTTP	false
Allowed browser origins	SENDMUX_MCP_ALLOWED_ORIGINS	no browser origins
Snapshot directory override	SENDMUX_MCP_OPENAPI_INPUT_DIR or OPENAPI_INPUT_DIR	packaged snapshots
App snapshot override	SENDMUX_MCP_APP_OPENAPI	packaged app snapshot
Sending snapshot override	SENDMUX_MCP_SENDING_OPENAPI	packaged sending snapshot
Request timeout	SENDMUX_MCP_TIMEOUT_SECONDS	30
Retry attempts	SENDMUX_MCP_RETRY_MAX_ATTEMPTS	3

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.