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The MCP Inspector provides a complete testing environment for your MCP server. Manually invoke tools, read resources, fetch prompts, and view all JSON-RPC messages between MCPJam and your server.
MCPJam MCP Inspector

Tools

Test your MCP tools by manually invoking them with custom parameters:
  • View all tools - Browse tool names, descriptions, and parameters
  • Search tools - Quickly find specific tools by name
  • Invoke tools - Trigger tools with custom input parameters
  • View results - See tool outputs, including widget responses for ChatGPT apps and MCP apps
  • Elicitation support - Handle elicitation requests from tools
  • Save requests - Save frequently used tool invocations for quick testing
Saved requests are stored in your browser’s local storage and accessible from the Saved Requests tab.

Resources

Inspect your MCP server’s resources:
  • Browse resources - View all available resources with names, URIs, and MIME types
  • Read resources - Fetch and view resource content
  • Resource templates - Test templated resources with dynamic parameters

Prompts

Test your MCP prompts:
  • View prompts - Browse prompt names, descriptions, and parameters
  • Fetch prompts - Retrieve prompt content with custom arguments
  • Use in playground - Type / in the LLM Playground to insert prompts directly into chat

JSON-RPC Logging

All communication between MCPJam and your MCP server is logged in real-time:
  • Request/response pairs - View complete JSON-RPC messages
  • Message types - See tool calls, resource reads, prompt fetches, and more
  • Error tracking - Inspect errors and validation issues
  • Timestamps - Track message timing and performance
The JSON-RPC logger helps you debug your MCP server implementation and understand the complete protocol flow.