Intermittent MCP tool discovery failure in Agent Builder (HTTP 424) but direct @openai/agents calls succeed

Hey @OpenAI_Support , quick update with an important change in behavior:

Starting Thursday, the Agent Builder workflow is no longer intermittently failing, it cannot connect at all even once. Tool discovery fails every time now.

To rule out any issues with the remote MCP server itself, I tested using MCP Inspector against the exact same endpoint and API key. MCP Inspector connects reliably and is able to:

List tools successfully

Execute tool calls without any issues

So the MCP server appears healthy, and the problem seems isolated specifically to Agent Builder’s MCP integration, not the backend.

Happy to share more logs or repro details if helpful.

Thanks again for looking into this.