dev-server sandbox instances

make dev-server starts the mux backend server, which uses a lockfile at:

• <MUX_ROOT>/server.lock (defaults to ~/.mux-dev/server.lock in development)

This means you can only run one dev server per mux root directory.

This skill documents the repo workflow for starting multiple dev-server instances in parallel (including from different git worktrees) by giving each instance its own temporary MUX_ROOT .

Quick start

make dev-server-sandbox

What it does

• Creates a fresh temporary MUX_ROOT directory

• Copies these files into the sandbox if present (unless disabled by flags):

• providers.jsonc (provider config)

• config.json (project list)

• Picks free ports (BACKEND_PORT , VITE_PORT )

• Allows all hosts (VITE_ALLOWED_HOSTS=all ) so it works behind port-forwarding domains

• Runs make dev-server with those env overrides

Options

Start with a clean instance (do not copy providers or projects)

make dev-server-sandbox DEV_SERVER_SANDBOX_ARGS="--clean-providers --clean-projects"

Skip copying providers.jsonc

make dev-server-sandbox DEV_SERVER_SANDBOX_ARGS="--clean-providers"

Clear projects from config.json (preserves other config)

make dev-server-sandbox DEV_SERVER_SANDBOX_ARGS="--clean-projects"

Use a specific root to seed from (defaults to ~/.mux-dev then ~/.mux)

SEED_MUX_ROOT=~/.mux-dev make dev-server-sandbox

Keep the sandbox root directory after exit (useful for debugging)

KEEP_SANDBOX=1 make dev-server-sandbox

Pin ports (must be different)

BACKEND_PORT=3001 VITE_PORT=5174 make dev-server-sandbox

Override which make binary to use

MAKE=gmake make dev-server-sandbox

Security notes

• providers.jsonc may contain API keys.

• The sandbox root directory is created on disk (usually under your system temp dir).

• This flow intentionally does not copy secrets.json .