inspector_usage.txt•2.71 kB
Inspector - Model Context Protocol
https://modelcontextprotocol.io/docs/tools/inspector
In-depth guide to using the MCP Inspector for testing and debugging Model Context Protocol servers
The MCP Inspector is an interactive developer tool for testing and debugging MCP servers. While the Debugging Guide covers the Inspector as part of the overall debugging toolkit, this document provides a detailed exploration of the Inspector’s features and capabilities.
Getting started
Installation and basic usage
The Inspector runs directly through npx without requiring installation:
npx @modelcontextprotocol/inspector <command>
npx @modelcontextprotocol/inspector <command> <arg1> <arg2>
Inspecting servers from NPM or PyPi
A common way to start server packages from NPM or PyPi.
NPM package
PyPi package
npx -y @modelcontextprotocol/inspector npx <package-name> <args>
# For example
npx -y @modelcontextprotocol/inspector npx server-postgres postgres://127.0.0.1/testdb
Inspecting locally developed servers
To inspect servers locally developed or downloaded as a repository, the most common way is:
TypeScript
Python
npx @modelcontextprotocol/inspector node path/to/server/index.js args...
Please carefully read any attached README for the most accurate instructions.
Feature overview
The MCP Inspector interface
The Inspector provides several features for interacting with your MCP server:
Server connection pane
Allows selecting the transport for connecting to the server
For local servers, supports customizing the command-line arguments and environment
Resources tab
Lists all available resources
Shows resource metadata (MIME types, descriptions)
Allows resource content inspection
Supports subscription testing
Prompts tab
Displays available prompt templates
Shows prompt arguments and descriptions
Enables prompt testing with custom arguments
Previews generated messages
Tools tab
Lists available tools
Shows tool schemas and descriptions
Enables tool testing with custom inputs
Displays tool execution results
Notifications pane
Presents all logs recorded from the server
Shows notifications received from the server
Best practices
Development workflow
Start Development
Launch Inspector with your server
Verify basic connectivity
Check capability negotiation
Iterative testing
Make server changes
Rebuild the server
Reconnect the Inspector
Test affected features
Monitor messages
Test edge cases
Invalid inputs
Missing prompt arguments
Concurrent operations
Verify error handling and error responses
Next steps
Inspector Repository
Check out the MCP Inspector source code
Debugging Guide
Learn about broader debugging strategies