MCP Debug
Command-line tool for debugging MCP servers
What is MCP Debug?
MCP Debug is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to command-line tool for debugging mcp servers
Command-line tool for debugging MCP servers
This server falls under the Developer Tools category on MCPgee, the world's largest MCP server directory with 33,000+ servers.
Features
- Command-line tool for debugging MCP servers
Use Cases
Maintainer
Works with
Installation
Manual Installation
npx mcp-debugConfiguration
Configuration Details
claude_desktop_config.json
Performance
Response Metrics
Resource Usage
How to Set Up and Use MCP Debug
mcp-debug is a command-line tool written in Go that lets developers inspect, test, and debug MCP servers without needing a full AI client. It can connect to any MCP server via HTTP or stdio, enumerate its capabilities, list available tools and resources, invoke tools interactively, and even run as an MCP server itself for meta-testing. It also supports OAuth 2.1 authentication with automatic discovery, making it suitable for testing both open and secured MCP endpoints.
Prerequisites
- Go 1.21 or newer (for installation via go install)
- An MCP server to connect to — local or remote, stdio or HTTP/SSE
- Network access to the MCP endpoint if using HTTP transport
- Optional: OAuth 2.1 credentials if the target server requires authentication
Install mcp-debug via Go
Install the binary directly using go install. The binary will be placed in your GOPATH/bin directory.
go install github.com/giantswarm/mcp-debug@latestEnsure the binary is on your PATH
Confirm the installation succeeded and the binary is accessible from your terminal.
export PATH=$PATH:$(go env GOPATH)/bin
mcp-debug --helpConnect to a local MCP server
Point mcp-debug at a running MCP server's HTTP endpoint to inspect its capabilities and available tools.
mcp-debug --endpoint http://localhost:8090/mcpUse interactive REPL mode
Launch the interactive REPL to explore tools, list resources, and call tools interactively against the connected server.
mcp-debug --endpoint http://localhost:8090/mcp --replConnect to an OAuth-protected server
Enable OAuth 2.1 authentication flow using the --oauth flag. The tool performs automatic discovery via RFC 9728 and RFC 8414.
mcp-debug --oauth --endpoint https://mcp.example.com/mcpRun mcp-debug as an MCP server
Start mcp-debug in server mode to expose its debugging capabilities as an MCP tool — useful for meta-testing or chaining with other clients.
mcp-debug --mcp-serverMCP Debug Examples
Client configuration
Claude Desktop configuration to run mcp-debug as an MCP server, exposing its debugging tools to Claude.
{
"mcpServers": {
"mcp-debug": {
"command": "mcp-debug",
"args": ["--mcp-server"]
}
}
}Prompts to try
Example CLI invocations and interactive session tasks when using mcp-debug.
- "mcp-debug --endpoint http://localhost:8090/mcp" — list server capabilities
- "mcp-debug --endpoint http://localhost:8090/mcp --repl" — open interactive session
- In REPL: "list tools" — show all available tools
- In REPL: "call get_file path=/README.md" — invoke a specific tool
- "mcp-debug --oauth --endpoint https://secure-mcp.example.com/mcp" — authenticate and connect"Troubleshooting MCP Debug
mcp-debug command not found after go install
Run export PATH=$PATH:$(go env GOPATH)/bin and add this line to your shell profile (~/.zshrc or ~/.bashrc). Then open a new terminal and retry.
Connection refused when using --endpoint
Confirm the target MCP server is running and accessible at the specified URL. For local servers, verify the port number and that the server process is active.
OAuth flow fails with discovery error
Ensure the server implements RFC 9728 (Protected Resource Metadata) or RFC 8414 (Authorization Server Metadata). Use --oauth-disable-cimd to force Dynamic Client Registration if the server does not support Client ID Metadata Documents.
Frequently Asked Questions about MCP Debug
What is MCP Debug?
MCP Debug is a Model Context Protocol (MCP) server that command-line tool for debugging mcp servers It connects AI assistants to external tools and data sources through a standardized interface.
How do I install MCP Debug?
Follow the installation instructions on the MCP Debug GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.
Which AI clients work with MCP Debug?
MCP Debug works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.
Is MCP Debug free to use?
Yes, MCP Debug is open source and available under the Apache-2.0 license. You can use it freely in both personal and commercial projects.
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