dev-desktop-sandbox

Original：🇺🇸 English

Translated

Run isolated mux desktop (Electron) instances (temp MUX_ROOT + free ports)

1installs

Sourcecoder/mux

Added on2026-02-28

NPX Install

npx skill4agent add coder/mux dev-desktop-sandbox

SKILL.md Content

View Translation Comparison →

Desktop (Electron) sandbox instances

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

.

Quick start

bash

make dev-desktop-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:
- Vite devserver port (used by the renderer)
- Electron remote debugging port (optional)

Runs

make dev

with:

```
MUX_ROOT=<temp>
```
```
MUX_VITE_PORT=<free-port>
```

Waits for Vite to be reachable, then runs
```
make build-static
```
(Electron expects
```
dist/splash.html
```
)

Launches Electron (

bunx electron .

) with:

```
MUX_ROOT=<temp>
```
```
MUX_DEVSERVER_HOST=127.0.0.1
```
```
MUX_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)

Options

bash

# 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

Optional: deeper Electron isolation (

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:

bash

MUX_E2E=1 make dev-desktop-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
```
.

dev-desktop-sandbox

NPX Install

Tags

SKILL.md Content

Desktop (Electron) sandbox instances

Quick start

What it does

Options

Optional: deeper Electron isolation (
`MUX_E2E=1`
)

Security notes

dev-desktop-sandbox

NPX Install

Tags

SKILL.md Content

Desktop (Electron) sandbox instances

Quick start

What it does

Options

Optional: deeper Electron isolation (MUX_E2E=1)

Security notes

Optional: deeper Electron isolation (
`MUX_E2E=1`
)