ChatGPT · MCP testing
Test how ChatGPT calls your MCP tools.
ChatGPT decides which tool to call and what to do with the result. In ChatGPT, the model sees images returned via direct content, embedded resources, and linked resources. MCPJam runs your server through ChatGPT with openai/gpt-5-nano so you see the real tool calls instead of guessing from a bug report.
npx @mcpjam/inspector@latestHow ChatGPT handles your tool results
Image results
Images reach the model via direct content, embedded resources, and linked resources. That covers every shape we track.
Emulation model
MCPJam drives ChatGPT with openai/gpt-5-nano, so tool selection reflects this host, not a generic model.
Extensions
ChatGPT advertises io.modelcontextprotocol/ui.
See the call
Trace shows every step from prompt to response with timings. The exact tool, the exact arguments.
Score it
Evals run realistic requests through ChatGPT and score whether the right tool was picked with the right arguments.
How we know
Vendor docs: Based on the vendor's published documentation. Last reviewed 2026-07-08.
Walkthrough: ChatGPT
Run npx @mcpjam/inspector@latest, connect the MCP server config you already use, and select ChatGPT as the host. MCPJam emulates ChatGPT with openai/gpt-5-nano on desktop, so what you see is this host's behavior, not a generic client's.
Ask for something in natural language and watch which tool ChatGPT picks and with what arguments. Open Trace for the timed step-by-step, then turn the recurring cases into an eval suite so a regression fails the gate instead of your users.
Frequently asked questions
Run npx @mcpjam/inspector@latest, connect your server, and select ChatGPT. MCPJam emulates the host with openai/gpt-5-nano, so you can watch the real behavior locally, free and open source.
In ChatGPT, images reach the model via direct content, embedded resources, and linked resources. (Catalog last reviewed 2026-07-08.)
MCPJam's host-compat catalog (the same data behind caniuse.dev). Vendor docs: Based on the vendor's published documentation. Last reviewed 2026-07-08.
See it in ChatGPT before your users do.
One command, your existing server config, ChatGPT's real behavior in the loop.
Open source · no credit card · ~2 min