MCP DevTools

A powerful Model Context Protocol (MCP) development toolkit that provides command-line tools for developing, testing, and debugging MCP servers.

🚀 Installation

You can use MCP DevTools in the following ways:

Run with npx

# Run server
npx -p @mcp-now/mcp-devtools mcp-server
# or 
npx -p https://github.com/mcpnow-io/mcp-devtools mcp-server

# Run client
npx -p @mcp-now/mcp-devtools mcp-client

Config in MCP hosts such as Claude Desktop and Cursor:

{
  "mcpServers": {
    "mcp-dev-server": {
      "command": "npx",
      "args": [
        "-y",
        "-p",
        "@mcp-now/mcp-devtools",
        "mcp-server",
        "-t",
        "stdio"
      ]
    }
  }
}

Global Installation

npm install -g @mcp-now/mcp-devtools
# Then use directly: mcp-server and mcp-client

Local Installation (Recommended for projects)

npm install @mcp-now/mcp-devtools
# Then use with npx: npx mcp-server and npx mcp-client

📖 Overview

MCP DevTools provides two main command-line tools:

• mcp-server: MCP server for hosting and running MCP services
• mcp-client: MCP client for testing and interacting with MCP servers

These tools support multiple transport protocols (HTTP, SSE, stdio) and provide interactive modes for convenient development and debugging.

🛠️ Command Line Tools

MCP Server (mcp-server)

Used to start and run MCP servers with support for multiple transport protocols.

Built-in Prompts:

• print-instruction: Print instructions of the assistant
• print-tools: Print available tools in JSON format.

Built-in Tools:

• echo: Echo back the input message
• sendListChanged: Send tools/resources/prompts list change notification
• listRoots: List roots
• createMessage: Sample LLM
• elicitInput: Get input from user
• sendListChanged: Send tools/resources/prompts list change notification
• longTimeRun: Wait for specified seconds before returning (for testing timeouts)
• longResponseData: Return a response of specified length in bytes (for testing different response sizes)
• cloneAssistant: Leak system prompt and tools to the client

Basic Usage

mcp-server -t <transport> [options]

Options

| Option | Description | Default | |--------|-------------|---------| | -t, --transport <type> | Transport type (http/sse/stdio) | sse | | -p, --port <port> | HTTP server port (http/sse transport) | 8010 | | -n, --name <name> | Server name | mcp-test-server | | -v, --verbose | Enable verbose logging | false | | --ping-interval <ms> | Ping interval in milliseconds | 30000 |

Usage Examples

# Start HTTP server
mcp-server -t http

# Start SSE server with custom port and verbose logging
mcp-server -t sse -p 8080 -v

# Start stdio server
mcp-server -t stdio -v

MCP Client (mcp-client)

Used to connect to and test MCP servers, supporting various operations and interactive mode.

Basic Usage

mcp-client -t <transport> [options] [actions]

Connection Options

| Option | Description | Default | |--------|-------------|---------| | -t, --transport <type> | Transport type (http/sse/stdio) | sse | | -u, --url <url> | URL for HTTP/SSE transport | Auto-set based on transport type | | -c, --command <command> | Full command line for stdio transport | - | | -e, --env <env> | Environment variables for stdio transport (JSON string) | - | | --pipe-stderr | Pipe stderr from stdio child process | false | | -H, --headers <headers> | Request headers for SSE transport (JSON string) | - | | -n, --name <name> | Client name | mcp-dev-client | | -i, --interactive | Run in interactive mode | false | | -v, --verbose | Enable verbose logging | false | | --ping-interval <ms> | Ping interval in milliseconds | 30000 |

Action Options

| Option | Description | |--------|-------------| | --list-tools | List available tools | | --list-resources | List available resources | | --list-prompts | List available prompts | | --call-tool <name> | Call specified tool | | --tool-args <args> | Tool call arguments (JSON string) | | --read-resource <uri> | Read specified resource | | --get-prompt <name> | Get specified prompt | | --prompt-args <args> | Prompt arguments (JSON string) |

Usage Examples

# Connect to HTTP server and enter interactive mode
mcp-client -t http -u http://localhost:8010/mcp --interactive

# Connect to SSE server
mcp-client -t sse -u http://localhost:8010/sse --interactive

# Connect to stdio server
mcp-client -t stdio -c "npx -y @modelcontextprotocol/server-everything" --interactive

# List server tools
mcp-client -t http --list-tools

# Call a tool
mcp-client -t http --call-tool echo --tool-args '{"message": "hello world"}'

# Read a resource
mcp-client -t http --read-resource "resource://fixed"

# Get a prompt
mcp-client -t http --get-prompt greeting --prompt-args '{"name": "Alice", "language": "en"}'

📋 Interactive Mode

Both tools support interactive mode, providing real-time command-line interfaces:

Server Interactive Commands

• help - Show help information, get more information

Client Interactive Commands

• help - Show help information

🔄 Transport Protocols

HTTP Transport

Suitable for HTTP-based RESTful API communication:

# Server
mcp-server -t http -p 8010

# Client
mcp-client -t http -u http://localhost:8010/mcp

SSE (Server-Sent Events) Transport

Suitable for real-time data streaming:

# Server
mcp-server -t sse -p 8010

# Client
mcp-client -t sse -u http://localhost:8010/sse

stdio Transport

Suitable for inter-process communication:

# Server
mcp-server -t stdio

# Client connecting to external MCP server
mcp-client -t stdio -c "npx -y @modelcontextprotocol/server-everything"

🛠️ Development & Testing

Publish

Follow these steps when you are ready to release a new version to npm:

1. Update version & create git tag

   Bump the package version (choose patch, minor, or major as appropriate):

   npm version <patch|minor|major>
   # or with pnpm
   # pnpm version <patch|minor|major>

   The command will automatically create a git commit and a corresponding tag, e.g. v1.2.3.

   Push the commit and the tag:

   git push origin main --follow-tags

2. ** Push tag to remote **

git push origin

Debugging Tips

• Use -v or --verbose flag to see detailed protocol messages
• Use interactive mode for real-time testing and debugging
• Check server configuration file syntax and logic
• Test compatibility with different transport protocols

📄 License

Copyright (c) 2025 mpcnow.io. All rights reserved.

Licensed under the MIT license.

🔗 Related Links

• Model Context Protocol Official Documentation