MCPJam Inspector gives you full visibility into every exchange between the inspector and your MCP server, across the Playground, Tools, Prompts, and Resources tabs.
JSON-RPC logging
Every tab that talks to a connected server renders a live JSON-RPC logger. Each entry records the direction (client → server or server → client), the method name, a timestamp, and the full request/response payload. Click an entry to expand and inspect.
See Playground → JSON-RPC Logger and MCP Inspector for how it surfaces in each tab.
When using ChatGPT Apps or MCP Apps in the Playground, you can debug widget state and globals directly from tool call results.
Debugging in the chat
Click on any tool call in the chat to expand its debug panel. For widgets, you’ll see three tabs:
- Data - The tool’s input arguments and output result
- Widget State - The current state persisted by the widget (updated in real-time as the widget calls
setWidgetState)
- Globals - Environment information passed to the widget including theme, display mode, locale, and device capabilities
A “Click to debug” hint appears on tool calls that have widget debug information available.
When testing OpenAI Apps or MCP Apps from the Tools tab, the results panel includes a State/Globals button alongside the Component and Raw JSON views. This shows the same widget state and globals information in a dedicated panel.
Widget state persists across follow-up turns in a conversation. Keep state
under 4k tokens for optimal performance.
