mcp-tool

A command-line tool for testing MCP (Model Context Protocol) servers. Uses the same mcp-go library as Sketch to provide manual testing capabilities for MCP server implementations.

Usage

Discover Tools

List all tools available from an MCP server:

mcp-tool discover -mcp '{"name": "server-name", "type": "stdio", "command": "./server"}'

Call Tools

Invoke a specific tool on an MCP server:

mcp-tool call -mcp '{"name": "server-name", "type": "stdio", "command": "./server"}' tool_name '{"arg1": "value1"}'

MCP Server Configuration

The -mcp flag accepts a JSON configuration with the following fields:

• name (required): Server name for identification
• type: Transport type - "stdio" (default), "http", or "sse"
• command: Command to run (for stdio transport)
• args: Array of command arguments (for stdio transport)
• url: Server URL (for http/sse transport)
• env: Environment variables as key-value pairs (for stdio transport)
• headers: HTTP headers as key-value pairs (for http/sse transport)

Examples

Stdio Transport

# Test a Python MCP server
mcp-tool discover -mcp '{"name": "python-server", "type": "stdio", "command": "python3", "args": ["server.py"]}'

# Call a tool with arguments
mcp-tool call -mcp '{"name": "python-server", "type": "stdio", "command": "python3", "args": ["server.py"]}' list_files '{"path": "/tmp"}'

HTTP Transport

# Discover tools from HTTP MCP server
mcp-tool discover -mcp '{"name": "http-server", "type": "http", "url": "http://localhost:8080/mcp"}'

# Call with custom headers
mcp-tool call -mcp '{"name": "http-server", "type": "http", "url": "http://localhost:8080/mcp", "headers": {"Authorization": "Bearer token"}}' get_data '{}'

SSE Transport

# Use Server-Sent Events transport
mcp-tool discover -mcp '{"name": "sse-server", "type": "sse", "url": "http://localhost:8080/mcp/sse"}'

Options

• -v: Verbose output for debugging
• -timeout duration: Connection timeout (default: 30s)

Testing

A test MCP server (test-mcp-server.py) is provided in the repository root for testing purposes. It implements basic tools like echo, list_files, and get_env:

# Start the test server and test it
mcp-tool discover -mcp '{"name": "test", "type": "stdio", "command": "python3", "args": ["test-mcp-server.py"]}'
mcp-tool call -mcp '{"name": "test", "type": "stdio", "command": "python3", "args": ["test-mcp-server.py"]}' echo '{"message": "Hello MCP!"}'