Run isolated mux desktop (Electron) instances (temp MUX_ROOT + free ports)
make dev + make start (Electron) uses MUX_ROOT for persisted state (config, sessions, worktrees, etc.). Running multiple Electron instances against the same mux root is noisy and risky during development.
This skill documents the repo workflow for starting multiple desktop dev instances in parallel (including from different git worktrees) by giving each instance its own temporary MUX_ROOT.
make dev-desktop-sandbox
MUX_ROOT directoryproviders.jsonc (provider config)config.jsonmake dev with:
MUX_ROOT=<temp>MUX_VITE_PORT=<free-port>make build-static (Electron expects dist/splash.html)bunx electron .) with:
MUX_ROOT=<temp>MUX_DEVSERVER_HOST=127.0.0.1MUX_DEVSERVER_PORT=<vite-port>MUX_SERVER_PORT=0 by default (avoids EADDRINUSE if your config.json pins apiServerPort)CMUX_ALLOW_MULTIPLE_INSTANCES=1 (so you can run alongside another dev instance)# Start with a clean instance (do not copy providers or projects)
make dev-desktop-sandbox DEV_DESKTOP_SANDBOX_ARGS="--clean-providers --clean-projects"
# Skip copying providers.jsonc
make dev-desktop-sandbox DEV_DESKTOP_SANDBOX_ARGS="--clean-providers"
# Clear projects from config.json (preserves other config)
make dev-desktop-sandbox DEV_DESKTOP_SANDBOX_ARGS="--clean-projects"
# Use a specific root to seed from (defaults to $MUX_ROOT then ~/.mux-dev then ~/.mux)
SEED_MUX_ROOT=~/.mux-dev make dev-desktop-sandbox
# Keep the sandbox root directory after exit (useful for debugging)
KEEP_SANDBOX=1 make dev-desktop-sandbox
# Pin Vite port
VITE_PORT=5174 make dev-desktop-sandbox
# Control how long we wait for Vite to come up (ms)
VITE_READY_TIMEOUT_MS=120000 make dev-desktop-sandbox
# Enable/pin Electron remote debugging port (defaults to an auto-picked free port)
ELECTRON_DEBUG_PORT=9223 make dev-desktop-sandbox
# Disable Electron remote debugging entirely
ELECTRON_DEBUG_PORT=0 make dev-desktop-sandbox
# Override the internal API server port (defaults to 0/random for sandboxes)
MUX_SERVER_PORT=3772 make dev-desktop-sandbox
# Override which make binary to use
MAKE=gmake make dev-desktop-sandbox
MUX_E2E=1)Even with a unique MUX_ROOT, Electron's userData directory (localStorage, window state, single-instance lock, etc.) is not automatically relocated unless MUX_E2E=1 is set.
If you want full isolation (including userData), run:
MUX_E2E=1 make dev-desktop-sandbox
providers.jsonc may contain API keys.secrets.json.