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.

FAQ from emqx_mcp_gateway

What protocols can the MCP Gateway bridge to?

The gateway bridges MCP/MQTT clients to MCP servers using HTTP, STDIO, or gRPC (via an EMQX plugin).

How is access control managed?

Access control is managed through Role‑Based Access Control (RBAC). Conditions in mcp_rbac.csv assign