MCPJam Inspector provides powerful debugging and monitoring capabilities to help you identify and resolve issues in your MCP server implementation quickly and efficiently.
Logs
View all messages being sent back and forth between MCPJam and your MCP server. The logger captures two types of traffic:
- MCP Server RPC: JSON-RPC messages between Inspector and your MCP servers (via STDIO/HTTP/SSE transports)
- UI Apps Traffic: Messages between the host and custom UI widgets (ChatGPT Apps and MCP Apps)
You can filter logs by source, clear all logs, or copy logs to clipboard. The logger streams server RPC traffic in real-time and displays up to 1000 recent messages. Tracing message levels are ERROR, WARNING, and TRACE.
When using OpenAI 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.
