MCP Extension

A Pi extension that connects to MCP (Model Context Protocol) servers and provides tools to interact with them.

Tools

mcp_list

List all available MCP tools with names and descriptions.

mcp_inspect

Show full tool signature as a JSDoc function stub.

Parameters:

Name	Type	Required	Description
tool	string	Yes	Name of the MCP tool to inspect

mcp_invoke

Call a single MCP tool with JSON parameters.

Parameters:

Name	Type	Required	Description
tool	string	Yes	Name of the MCP tool to invoke
params	object	No	Parameters to pass to the tool

mcp_exec

Execute JavaScript code to orchestrate multiple MCP tool calls with logic.

Parameters:

Name	Type	Required	Description
code	string	Yes	JavaScript code using mcp.callTool(name, params)

Configuration

Create mcp.json in your Pi agent directory to configure MCP servers.

Config file location: $PI_CODING_AGENT_DIR/mcp.json (defaults to ~/.pi/agent/mcp.json)

Requirements

This extension depends on the mh CLI from MCP Hub.

Automatic Installation

The mh binary is automatically installed during npm install via the postinstall script. It will be installed to ~/.local/bin/ (or $XDG_BIN_HOME if set).

Manual Installation

If automatic installation fails, you can install mh manually:

# Using the install script
curl -fsSL https://raw.githubusercontent.com/vaayne/mcphub/main/scripts/install.sh | sh

# Or build from source
git clone https://github.com/vaayne/mcphub.git
cd mcphub
go build -o ~/.local/bin/mh .

Ensure ~/.local/bin is in your PATH:

export PATH="$PATH:$HOME/.local/bin"