Unable to create Secure MCP Tunnel: tenant context missing / fallback_missing_entry

ChatGPT Apps SDK
,
1

Hi,

I’m trying to create an OpenAI Secure MCP Tunnel for a local MCP server that I want to use from a ChatGPT custom connector.

My intended setup is:

ChatGPT custom connector
  -> Connection = Tunnel
  -> OpenAI Secure MCP Tunnel
  -> local tunnel-client
  -> local MCP server at http://127.0.0.1:8000/mcp

I understand that ChatGPT does not accept a direct local HTTP MCP URL like http://localhost:8000/mcp, so I’m trying to use the Tunnel option instead.

In Platform settings, I created two custom roles:

  • Tunnel Manager: Tunnels Read + Manage

  • Tunnel User: Tunnels Read + Use

I assigned both roles to my user.

Then I went to Platform → Organization → Tunnels and tried to create a tunnel with:

Name: llmgw
Description: local MCP tunnel
Organization IDs: my current org ID
Workspace IDs: empty

The UI shows a generic toast:

Failed to create tunnel. Please try again.

The Network response contains:

{
  "error": {
    "message": "403: Tenant context missing and no allowlist is configured for the active organization. (reason=fallback_missing_entry) (request_id=req_09e00d1c231347b48dcc8a5ed305605f)",
    "type": "server_error",
    "param": null,
    "code": null
  }
}

This looks somewhat related to another private MCP connector issue mentioning a missing access_list, but in my case the backend says fallback_missing_entry.

Questions:

  1. Is Secure MCP Tunnel currently available for personal Platform organizations / personal ChatGPT accounts?

  2. Is a ChatGPT Workspace ID required to create a tunnel?

  3. If yes, where can I find the correct workspace-... ID for a personal ChatGPT workspace?

  4. Does fallback_missing_entry mean my organization needs to be allowlisted before Secure MCP Tunnel can be used?

  5. What is the expected relationship between Platform organizations, Platform projects, ChatGPT workspaces, and Secure MCP Tunnel scope?

I’m not trying to report a billing issue. I’m trying to understand the correct Apps SDK / MCP tunnel setup for local development with ChatGPT connectors.

Thanks!

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2

I can confirm the same issue.

Organization owner access confirmed.
Billing enabled.
Tunnel permissions assigned.
Tunnel creation UI is available.

Creating a tunnel fails with:

403: Tenant context missing and no allowlist is configured for the active organization.
(reason=fallback_missing_entry)

Personal organization.
Project exists.

Has anyone found a workaround?

3

Thanks for raising this issue!
I have pinged the team to take a look.