`MCPX_DOCKER_NO_PERMISSION`

Severity: error Domain: Docker

What happened

The Docker daemon is up, but the user mcpproxy is running as does not have permission to connect to the Docker socket (/var/run/docker.sock on Linux/macOS).

How to fix

Linux — add the user to the `docker` group

bash

sudo usermod -aG docker "$USER"
newgrp docker          # apply in the current shell without logging out
docker info            # verify

You may need to log out and back in for GUI apps (the tray) to pick up the new group.

macOS — check Docker Desktop permissions

Docker Desktop usually grants access automatically. If not:

Reinstall Docker Desktop (it re-creates the socket symlink with the right perms).
Or use Colima, which runs as the current user without socket-permission issues.

Rootless Docker

If you're using rootless Docker, make sure DOCKER_HOST points at the rootless socket and the systemd user service is running:

bash

systemctl --user status docker
echo "$DOCKER_HOST"     # typically unix:///run/user/<uid>/docker.sock

Avoid setuid hacks

Don't chmod 666 /var/run/docker.sock — that gives every local process root escalation via Docker. Adding the user to the docker group is the safe, canonical fix (and is documented to grant root-equivalent privileges).

MCPX_DOCKER_NO_PERMISSION