MCP-CLI

MCP-CLI is a command-line tool for interacting with and testing Model Context Protocol (MCP) servers. It provides a user-friendly terminal user interface (TUI) for selecting and executing tools offered by an MCP server.

Features

• Multiple Transports: Connect to MCP servers using stdio, sse (Server-Sent Events), or http (streamable HTTP).
• Interactive TUI: A terminal user interface built with bubbletea that allows you to:
  • Select a tool from a list of available tools.
  • Enter arguments for the selected tool in a form.
  • View the results of the tool execution.
• Debug Panel: A scrollable debug panel on the right side of the TUI that shows:
  • Informational logs (key presses, state changes).
  • The arguments sent to the tool in a pretty-printed JSON format.
  • The results of tool calls.
• Verbose Logging: Use the -v flag to enable verbose logging to a debug.log file for troubleshooting.

Installation

You can install mcp-cli using go install:

go install mcp-cli

Alternatively, you can build it from source.

Building from Source

1. Clone the repository:

   git clone <repository-url>
   cd mcp-cli

2. Build the executable:

   go build

   This will create an mcp-cli executable in the current directory.

Usage

The mcp-cli tool has three main commands, one for each transport protocol.

stdio

Connect to an MCP server that communicates over standard input/output.

mcp-cli stdio --env "VAR=value" --env "ANOTHER_VAR=another_value" "<command-to-start-server>"

The --env (or -e) flag can be used multiple times to pass environment variables to the server process.

Example:

mcp-cli stdio -e "API_KEY=12345" "python /path/to/mcp/server.py"

sse

Connect to an MCP server that uses Server-Sent Events (SSE).

mcp-cli sse --header "Header-Name: header-value" <server-url>

The --header (or -H) flag can be used multiple times to pass custom HTTP headers to the server.

Example:

mcp-cli sse -H "Authorization: Bearer my-token" http://localhost:8080/mcp

http

Connect to an MCP server that uses streamable HTTP.

mcp-cli http --header "Header-Name: header-value" <server-url>

The --header (or -H) flag can be used multiple times to pass custom HTTP headers to the server.

Example:

mcp-cli http -H "Authorization: Bearer my-token" http://localhost:8080/mcp

Global Flags

• -v, --verbose: Enable verbose logging to debug.log.

TUI Guide

When you connect to an MCP server, you will be presented with a terminal user interface.

• Tool Selection View: A list of available tools. Use the arrow keys to navigate and press Enter to select a tool.
• Argument Input View: A form for entering the arguments for the selected tool. Use Tab to switch between fields and Enter to submit the tool call.
• Result View: Shows the result of the tool execution. Press Enter to return to the argument input view for the same tool, allowing you to easily call it again with different arguments.
• Debug Panel: The right-hand panel shows a scrollable log of events, tool calls, and results. Use the up and down arrow keys to scroll through the log.
• Navigation:
  • Esc: Return to the tool selection view.
  • Ctrl+C: Exit the application.