Why use Docker runtime
- Full isolation: Each workspace runs in its own container with no shared state
- Reproducible environments: Pin exact images for consistent tooling
- Security: Container sandboxing limits agent access to host system
How it works
- When you create a Docker workspace, Mux starts a container from your chosen image
- Your project code is synced to
/srcinside the container via git bundle - Commands run inside the container with
docker exec - Deleting the workspace removes the container
Configuration
Select Docker in the workspace creation UI and specify an image:node:20- Node.js with git pre-installedpython:3.12- Python with git pre-installed- Custom images with your toolchain
Credential sharing
Check “Share credentials” when creating a Docker workspace to enable git authentication:- SSH agent forwarding — Your SSH keys work inside the container without copying private keys
- Git config — Host
~/.gitconfigis copied into the container so git has your identity and settings - GitHub CLI — If
GH_TOKENis set in project secrets, Mux runsgh auth setup-gitto configure HTTPS authentication (requiresghCLI in the container image)