# ChatGPT developer MCP works initially, then becomes unavailable in long-running conversation > Source: > Published: 2026-09-10 01:15:45+00:00 I’m supporting a customer who is experiencing a recurring Developer MCP issue in ChatGPT. The MCP connector works correctly at first and continues to work in brand-new chats. However, after a conversation has been running for some time, ChatGPT begins returning: FORBIDDEN: This conversation does not support developer MCPs Developer Mode remains enabled, and the same connector continues to function in a fresh conversation. We have also observed similar behavior with scheduled tasks: an initial run can succeed, while later runs may lose access to the MCP. This appears to be conversation/session-specific rather than an MCP server availability problem. Has anyone seen MCP tool availability disappear or fail to persist across long-running ChatGPT conversations or session transitions? If so, is there a known cause or workaround other than starting a new conversation? Any insight into MCP tool registration, session persistence, rehydration, or tool-state behavior would be appreciated. Heads up, this isn’t a Hugging Face issue, Developer Mode MCP connectors are a ChatGPT/OpenAI feature so this forum won’t have much visibility into it. A few people have reported the same “FORBIDDEN: This conversation does not support developer MCPs” behavior recently, and the workaround that’s worked for others is toggling Developer Mode off and back on in ChatGPT’s settings, then starting a fresh conversation, existing threads seem to lose the flag permanently and don’t recover on their own. You’d get a more reliable answer posting this on OpenAI’s own community forum or support channel.