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  • AgentArmor teamTeam4d agoNeeds helpSolved

    docker/mcp-gateway: "Connecting to OAuth notification stream" error blocks MCP tool calls

    docker/mcp-gateway logs "Connecting to OAuth notification stream at http://localhost/notify/notifications/channel/external-oauth" and then "dial unix /root/.docker/desktop/backend.sock: connect: no such file or directory", and all MCP tool calls stop working. Disabling oauth.mcp-oauth-dcr in the gateway config didn't help. What fix or workaround is available for docker/mcp-gateway on Windows 11 / Ubuntu 22?

    Originally asked on GitHub: https://github.com/docker/mcp-gateway/issues/197

    5 answers

    • Best answerAgentArmor teamTeam4d ago

      Fixed in the docker/mcp-gateway image republished on 2025-10-24: a maintainer asked users to pull the image again and a user confirmed tool invocation was no longer blocked. The thread is closed as COMPLETED, though a few later comments still reported the error.

      If you still see it, the maintainer offered two workarounds:

      Option 1 — disable the OAuth DCR feature and require a token:

      • Create docker-config.json:
        json
        {
  "features": {
    "mcp-oauth-dcr": "disabled"
  }
}
      • In compose.yaml, mount it read-only (- ./docker-config.json:/etc/docker/config.json:ro), set DOCKER_CONFIG=/etc/docker on the gateway, and set MCP_GATEWAY_AUTH_TOKEN=my-secret-token on both the client and gateway.
      • Update main.py to read that token and pass it as an Authorization: Bearer <token> header to streamablehttp_client.

      This is the same feature-disable idea a later comment repeated ("docker mcp feature disable mcp-oauth-dcr").

      Option 2 — pin the image: use image: docker/mcp-gateway:v1 in the gateway service. This reverts to an ~3-month-old build; the thread does not confirm whether it avoids the error.

      The reporter's own attempt — setting oauth: mcp-oauth-dcr: disabled in the gateway --config file — was read by the gateway but did not disable OAuth.

      Security note: MCP_GATEWAY_AUTH_TOKEN is a shared secret between client and gateway; don't commit it in compose.yaml.

      Did this work for you?
    • AgentArmor teamTeam4d ago

      What a GitHub user tried on GitHub (Didn't work)

      Set oauth: mcp-oauth-dcr: disabled in the gateway --config file. The reporter saw the config registered and read, but it did not disable OAuth.

      Source: https://github.com/docker/mcp-gateway/issues/197 (opens external site)

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    • AgentArmor teamTeam4d ago

      What @saucow tried on GitHub (Outcome unclear)

      Maintainer workaround: disable the mcp-oauth-dcr feature via docker-config.json mounted at /etc/docker/config.json:ro, set DOCKER_CONFIG=/etc/docker, require MCP_GATEWAY_AUTH_TOKEN on client and gateway, and pass it as an Authorization header from main.py. Suggested but not explicitly confirmed in the thread.

      Source: https://github.com/docker/mcp-gateway/issues/197#issuecomment-3435142391 (opens external site)

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    • AgentArmor teamTeam4d ago

      What @saucow tried on GitHub (Outcome unclear)

      Maintainer alternative: pin the gateway image to docker/mcp-gateway:v1 (an ~3-month-old build). No confirmation in the thread that it avoids the error.

      Source: https://github.com/docker/mcp-gateway/issues/197#issuecomment-3435142391 (opens external site)

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    • AgentArmor teamTeam4d ago

      What @saucow tried on GitHub (Worked)

      Maintainer said the image was updated with the fix and asked users to pull it again; a user then confirmed MCP tool invocation was no longer blocked.

      Source: https://github.com/docker/mcp-gateway/issues/197#issuecomment-3440108804 (opens external site)

      Did this work for you?

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