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  "path": "/t/chatgpt-developer-mode-works-with-remote-serena-mcp-server-but-cloudflare-tunnel-logs-repeated-stream-canceled-errors/1376967#post_1",
  "publishedAt": "2026-03-17T08:54:18.000Z",
  "site": "https://community.openai.com",
  "textContent": "\n    Hi, I’m testing a remote MCP server with **ChatGPT Developer Mode** and I’m trying to understand whether the following Cloudflare Tunnel errors are expected/benign or whether they indicate a compatibility issue.\n\n    **Setup**\n\n    * ChatGPT Plus, Developer Mode\n    * Remote MCP server exposed over HTTPS via Cloudflare Tunnel\n    * Public MCP URL: `https://<my-mcp-domain>/mcp`\n    * Origin: Serena running locally on `http://localhost:8000`\n    * Serena started with `--transport streamable-http --context chatgpt`\n\n    **Observed behavior**\n    The MCP setup appears to work, but Cloudflare Tunnel repeatedly logs errors like:\n\n    ```text\n    ERR error=\"stream <id> canceled by remote with error code 0\"\n    ERR Request failed error=\"stream <id> canceled by remote with error code 0\" dest=https://<my-mcp-domain>/mcp\n    ```\n\n    I removed the exact domain name and Cloudflare edge IPs for privacy.\n\n    To clarify: I am **not** saying the connection drops or that ChatGPT disconnects. The issue is that the tunnel produces these error messages during MCP use.\n\n    **Server-side behavior**\n    Serena itself starts normally:\n\n    * MCP server starts\n    * StreamableHTTP session manager starts\n    * Uvicorn listens on `0.0.0.0:8000`\n    * language server initializes successfully\n\n    So this does not look like a basic Serena startup problem.\n\n    **Questions**\n\n    1. Are these Cloudflare Tunnel messages expected when ChatGPT Developer Mode uses a remote MCP server over `streamable-http`?\n    2. Are there known issues with ChatGPT Developer Mode and Cloudflare Tunnel for MCP traffic?\n    3. Does ChatGPT currently require or strongly depend on tool annotations such as `readOnlyHint` for custom MCP servers?\n    4. Is there a recommended way to distinguish harmless tunnel log noise from a real MCP transport/protocol problem?\n",
  "title": "ChatGPT Developer Mode works with remote Serena MCP server, but Cloudflare Tunnel logs repeated stream-canceled errors"
}