About MCP Server MetaTool
MCP Server MetaTool is an unmaintained proxy that combines tools from multiple MCP servers and routes calls to the corresponding server. It gets server configuration from metatool-app and is intended to be used with that GUI manager.
Key features
- 01Combines tools from multiple servers
- 02Routes calls to the matching server
- 03Retrieves configuration from metatool-app
- 04Separates tools by namespace
Use cases
- 01Presenting several MCP servers to one client
- 02Routing tool calls across configured servers
MCP support
Acts as both an MCP client and an MCP server: it connects to configured MCP servers, presents their tools to MCP clients, and forwards calls. The project is no longer maintained.
Configuration
Local server config is the same for every client. Copy it into your client’s MCP config file.
Tools
Local servers expose tools only once running on your machine, and the maintainer has not provided a tool list.
Details
From the project READMEMCP Server MetaTool
⚠️ This repo is no longer maintained!
Check out this Node.js substitute: metatool-ai/mcp-server-metamcp.
It has way better performance and fewer bugs.
(I am the author there too.)
Overview
Metatool MCP Server is a proxy server that joins multiple MCP servers and forward tool calls to the appropriate server. It should be used with metatool-app, the GUI tool manager for MCP which is also open source, together.
sequenceDiagram
participant MCPClient as MCP Client (e.g. Claude Desktop)
participant MetaToolMCP as MetaTool MCP Server
participant MetaToolApp as MetaTool App
participant MCPServers as Installed MCP Servers in Metatool App
MCPClient ->> MetaToolMCP: Request list tools
MetaToolMCP ->> MetaToolApp: Get tools configuration & status
MetaToolApp ->> MetaToolMCP: Return tools configuration & status
loop For each listed MCP Server
MetaToolMCP ->> MCPServers: Request list_tools
MCPServers ->> MetaToolMCP: Return list of tools
end
MetaToolMCP ->> MetaToolMCP: Aggregate tool lists
MetaToolMCP ->> MCPClient: Return aggregated list of tools
MCPClient ->> MetaToolMCP: Call tool
MetaToolMCP ->> MCPServers: call_tool to target MCP Server
MCPServers ->> MetaToolMCP: Return tool response
MetaToolMCP ->> MCPClient: Return tool response
How it works
- mcp-server-metatool itself is both a MCP client and a MCP server
- On startup, it connects to the metatool-app API to get a list of MCP servers to connect to
- On
list_toolscall of MCP, it joins all tools from all MCP servers with namespace isolation. - On
call_toolcall of MCP, it forwards the call to the appropriate server.
Installation
Best way to use this is through uv A METATOOL_API_KEY environment variable must be set
export METATOOL_API_KEY="my_api_key" # get from metatool-ai/metatool-app, which is self hostable and free
uvx mcp-server-metatool
You need a MCP Client to connect to this server to use it.
Additional Configuration
A METATOOL_API_BASE_URL environment variable can be set to point to another metatool instance
export METATOOL_API_BASE_URL="http://localhost:12005"
License
Apache License 2.0
Comments
New to MCP?
From what the protocol is to installing your first server, these answers cover most first questions.
An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.