Emqx MCP Gateway

What is emqx_mcp_gateway?

The emqx_mcp_gateway is an EMQX plugin that acts as a gateway, enabling MCP clients using the MCP over MQTT protocol to interact with MCP servers using other protocols (HTTP, STDIO, or gRPC).

How to use emqx_mcp_gateway?

Configure the plugin by preparing CSV files for server name mapping (mcp_server_name.csv), server name filters (mcp_server_name_filter.csv), and RBAC (mcp_rbac.csv). Add STDIO or HTTP MCP servers to the EMQX configuration file using HOCON blocks. The gateway automatically sets ACLs based on the configuration.

Key features of emqx_mcp_gateway

• Bridges MCP/MQTT clients to MCP servers via HTTP, STDIO, or gRPC.
• Configurable server name mapping using CSV conditions with Variform Expressions.
• Server name filters to restrict client access to allowed MCP servers.
• Role‑Based Access Control (RBAC) for MCP tools and resources.
• Automatic ACL enforcement derived from server names and filters.
• Supports variable substitution in server names from MCP metadata.

Use cases of emqx_mcp_gateway

• Connect MQTT‑based MCP clients to existing HTTP MCP servers.
• Expose local STDIO MCP servers (e.g., Python scripts) to MQTT clients.
• Provide fine‑grained access control to MCP tools and resources via RBAC.
• Manage multiple MCP servers with a consistent, broker‑enforced naming convention.