McpMux: one gateway for MCP servers

Install

Works in

• Claude Code
• Cursor
• Claude Desktop
• Windsurf
• VS Code
• SourceCraft
• Koda
• Coddy

Manual install

{"mcpServers":{"mcpmux":{"type":"http","url":"http://localhost:45818/mcp"}}}

What it does

McpMux is a desktop app written in Rust and Tauri 2 for Windows, macOS and Linux. It runs a local MCP gateway at http://localhost:45818/mcp, and every client, whether Cursor, Claude Desktop, VS Code, Windsurf or Claude Code, gets all servers from one config. Add a server in McpMux and it appears in every client with no restart. Servers install from a built-in registry of more than a hundred entries or are added by hand. Keys and OAuth tokens live in the operating system keychain, and clients' plain JSON files do not hold them. Workspaces (Spaces) separate servers, credentials and permissions, for example for work and for personal projects. Feature Sets limit which tools, prompts and resources a client sees, and a folder binding picks the set for the open project. Built-in tools mcpmux_list_spaces, mcpmux_list_all_tools, mcpmux_search_tools, mcpmux_manage_feature_set and mcpmux_bind_current_workspace help an agent assemble a short toolset for itself. A request starting with `@mux` triggers them, and changes go through an approval dialog.

Who it is for. Developers who use several AI clients and are tired of copying the same set of MCP servers and keys into four configs.

Example request

@mux build a minimal toolset for this Next.js repository and pin it to the current folder

MCP

Transport

http

Authentication

OAuth

Limitations

McpMux installs as an app: installers are at mcpmux.com/download and the README has no install command. The gateway listens on 127.0.0.1 only, so it serves clients on the same machine.

The license is GPL v3, and the app updates itself on launch by default, which can be switched off in settings. Cloud sync is, by the authors' account, still planned. Every tool call goes through the intermediary, so its permissions and bugs affect every connected client. The registry name com.mcpmux matches the project domain.

How to disable. Remove the mcpmux entry from each client's config and quit the app. Keys of servers added to McpMux live in the system keychain, so revoke them there or at the services themselves.

README in short

The README describes the problem of duplicated configs across clients, the gateway design, workspaces, feature sets, self-tuning through @mux and the security model. It links to the site with the server registry, the download page and Discord. The license is GPL v3.