Devbox Skill

Devboxes are OpenClaw sandbox containers running a custom image with VSCode Web, noVNC, Chromium (CDP), and up to 5 app ports routed via Traefik or Cloudflare Tunnels.

OpenClaw manages the full container lifecycle. Containers self-register — the entrypoint auto-assigns an ID, writes Traefik routes, and builds APP_URL_* env vars. The main agent just spawns and reports URLs.

File Locations

Resolve paths relative to this SKILL.md's parent directory.

Key files:

• •references/setup-script-guide.md — conventions for project setup scripts (.openclaw/setup.sh)

Architecture

• •Agent id: devbox (configured in openclaw.json)
• •Sandbox mode: all / scope: session — one container per session
• •Image: ghcr.io/adshrc/openclaw-devbox:latest (pulled from GHCR)
• •Network: traefik (for Traefik routing) or default Docker network (for Cloudflare Tunnel routing)
• •Browser: sandbox.browser.enabled: true, CDP on port 9222

Self-Registration (entrypoint)

The container's entrypoint automatically:

1. •Reads and increments /shared/.devbox-counter → assigns DEVBOX_ID
2. •Builds APP_URL_1..5, VSCODE_URL, NOVNC_URL from tags + domain + ID
3. •Writes /etc/devbox.env and /etc/profile.d/devbox.sh (available in all shells)
4. •Routes based on ROUTING_MODE:
   • •traefik (default): Writes Traefik config to /traefik/devbox-{id}.yml
   • •cloudflared: Generates cloudflared ingress config, registers DNS CNAME records via CF API, starts cloudflared tunnel run

Bind Mounts (configured in openclaw.json)

Important: Both paths must be writable by the sandbox containers (UID 1000). The counter file needs chmod 666, and the Traefik devboxes dir should be owned by 1000:1000 (set up during host provisioning).

Known Paths

These paths are always the same inside the OpenClaw container:

• •OpenClaw data: /home/node/.openclaw
• •Traefik dynamic config: /home/node/.openclaw/traefik (must be mounted into the OpenClaw container; only if using Traefik routing)

Onboarding Flow

Important: After this skill is installed, the next step must be this onboarding flow. The user CANNOT use the devbox skill until the onboarding flow is completed and the infrastructure is set up.

This runs on the MAIN agent, NOT in a sandbox. The main agent has access to exec, gateway, and the file system.

When the user asks to set up the devbox skill, do the following:

Step 1: Verify Docker prerequisites

Verify that you have access to the Docker socket and Docker binary:

which docker
docker version

If not, abort here and tell the user they need to run the OpenClaw container with:

-v /usr/bin/docker:/usr/bin/docker:ro
-v /var/run/docker.sock:/var/run/docker.sock

and that they need to set chmod 666 /var/run/docker.sock manually on the host, so that the OpenClaw container can work with it.

The OpenClaw container needs to be restarted then. After that, they can ask to set up the devbox skill again.

Step 2: Validate the Host Mapping Path

Find out what the host path/mapping is for /home/node/.openclaw inside the container:

# Returns the host path that is mapped to /home/node/.openclaw inside the container
docker inspect --format='{{range .Mounts}}{{if eq .Destination "/home/node/.openclaw"}}{{.Source}}{{end}}{{end}}' $(hostname)

Store the value as HOST_OPENCLAW_PATH. If HOST_OPENCLAW_PATH is a "system directory", OpenClaw will not be able to spawn a devbox.

System directories are: /etc, /private/etc, /proc, /sys, /dev, /root, /boot, /run, /var/run, /private/var/run, /var/run/docker.sock, /private/var/run/docker.sock and /run/docker.sock.

If the HOST_OPENCLAW_PATH is such a "system directory", abort here and tell the user they need to change their OpenClaw container setup to use a host path for OpenClaw data that is not a system directory. For example, they can create a directory like /home/openclaw or /opt/openclaw on the host.

Step 3: Gather info and detect paths

Ask the user for:

• •Routing mode: Traefik or Cloudflare Tunnel?
• •Domain: with wildcard A-Record pointing to the server (e.g. *.example.com)
• •GitHub token (optional): for cloning private repos inside devboxes

If Cloudflare Tunnel is chosen, also ask for:

• •Cloudflare API token: must have permissions for the zone (DNS edit + Tunnel edit)

Step 4: Verify prerequisites

If routing mode is Traefik:

# Check that /home/node/.openclaw/traefik is mounted
ls /home/node/.openclaw/traefik

If /home/node/.openclaw/traefik doesn't exist, tell the user they need to add e.g. -v path_to_traefik:/home/node/.openclaw/traefik to their OpenClaw container and restart it.

If routing mode is Cloudflare Tunnel:

Validate the CF API token and domain:

# 1. Verify token is valid
curl -s -X GET "https://api.cloudflare.com/client/v4/user/tokens/verify" \
  -H "Authorization: Bearer ${CF_API_TOKEN}" | jq .

# 2. Get zone ID for the domain (extract root domain from the provided domain)
curl -s -X GET "https://api.cloudflare.com/client/v4/zones?name=${ROOT_DOMAIN}" \
  -H "Authorization: Bearer ${CF_API_TOKEN}" | jq .

# 3. Get account ID from the zone response
# account_id = .result[0].account.id
# zone_id = .result[0].id

Then create the tunnel:

# 4. Create a named tunnel
curl -s -X POST "https://api.cloudflare.com/client/v4/accounts/${CF_ACCOUNT_ID}/cfd_tunnel" \
  -H "Authorization: Bearer ${CF_API_TOKEN}" \
  -H "Content-Type: application/json" \
  -d '{"name": "openclaw-devboxes", "tunnel_secret": "'$(openssl rand -base64 32)'"}' | jq .

# Extract tunnel_id and tunnel_token from the response
# tunnel_id = .result.id
# tunnel_token = .result.token

Store the values: CF_API_TOKEN, CF_ZONE_ID, CF_ACCOUNT_ID, CF_TUNNEL_ID, CF_TUNNEL_TOKEN.

Step 5: Create counter file

echo "0" > /home/node/.openclaw/.devbox-counter
chmod 666 /home/node/.openclaw/.devbox-counter

Important: The counter is never reset, it just keeps incrementing.

Step 6: Configure OpenClaw

First, check the current "agents" config:

node /app/openclaw.mjs config get agents

Then, decice what needs to be adjusted based on the existing config:

Main Agent

IF there is an agent with default: true, note its index and add subagents.allowAgents to it:

node /app/openclaw.mjs config set agents.list[{index}].subagents.allowAgents '["devbox"]' --json

then (if needed), set sandbox mode to off (since the main agent doesn't need a sandbox):

node /app/openclaw.mjs config set agents.list[{index}].sandbox.mode "off"

ELSE there's no agent with default: true, create one at the next index with the necessary structure:

node /app/openclaw.mjs config set agents.list[{index}] '{
  "id": "main",
  "default": true,
  "subagents": {
    "allowAgents": [
        "devbox"
    ]
  },
  "sandbox": {
    "mode": "off"
  }
}' --json

Devbox Agent

1. •Pull the Docker image so that it's available when OpenClaw tries to spawn it:

docker pull ghcr.io/adshrc/openclaw-devbox:latest

1. •Add the devbox agent at the next index in agents.list. Adjust the sandbox and docker config as needed (replace placeholders in curly brackets):

node /app/openclaw.mjs config set agents.list[{index}] '{
    "id": "devbox",
    "name": "Devbox Agent",
    "sandbox": {
      "mode": "all",
      "workspaceAccess": "none",
      "scope": "session",
      "docker": {
        "image": "ghcr.io/adshrc/openclaw-devbox:latest",
        "readOnlyRoot": false,
        "network": "traefik", # Only needed for Traefik routing mode, exclude otherwise
        "env": {
          "ENABLE_VNC": "true",
          "ENABLE_VSCODE": "true",
          "DEVBOX_DOMAIN": "{domain}",
          "APP_TAG_1": "app1",
          "APP_TAG_2": "app2",
          "APP_TAG_3": "app3",
          "APP_TAG_4": "app4",
          "APP_TAG_5": "app5",
          "GITHUB_TOKEN": "{github_token}",
          "ROUTING_MODE": "{traefik|cloudflared}",
          # Cloudflare Tunnel variables (only needed if using cloudflared routing, exclude otherwise)
          "CF_TUNNEL_TOKEN": "{cf_tunnel_token}",
          "CF_API_TOKEN": "{cf_api_token}",
          "CF_ZONE_ID": "{cf_zone_id}",
          "CF_TUNNEL_ID": "{cf_tunnel_id}",
        },
        "binds": [
          "{host_openclaw_path}/.devbox-counter:/shared/.devbox-counter:rw",
          "{host_openclaw_path}/traefik:/traefik:rw" # Only needed for Traefik routing mode, exclude otherwise
        ]
      },
      "browser": {
        "enabled": true,
        "cdpPort": 9222
      },
      "prune": {
        "idleHours": 0,
        "maxAgeDays": 0
      }
    }
  }
]' --json

1. •Allow Agents to communicate with each other so that subsequent tasks can be sent to the devbox agent:

node /app/openclaw.mjs config set tools.agentToAgent.enabled true
node /app/openclaw.mjs config set tools.sessions.visibility "all"

After this is done, restart the gateway to apply the changes. If this is not working (e.g. command is disabled), ask the user to restart the OpenClaw container manually.

Workflow: Spawn a Devbox

Step 1: Spawn subagent (main agent)

sessions_spawn(
    agentId="devbox",
    label="devbox-{task_name}",
    task="Your task description. GitHub token is in $GITHUB_TOKEN. Env vars (DEVBOX_ID, APP_URL_*, etc.) are in your shell via `source /etc/profile.d/devbox.sh`. ALWAYS use /workspace as the working directory! When cloning, the structure must be /workspace/<repo>."
)

That's it! The container self-registers. No manual ID assignment or Traefik setup needed.

Step 2: Report URLs to user (main agent)

Read the counter to know the assigned ID, then report:

DEVBOX_ID=$(cat .devbox-counter)

• •VSCode: https://vscode-{id}.{domain}
• •noVNC: https://novnc-{id}.{domain}/vnc.html
• •App URLs: https://{tag}-{id}.{domain}

Cleanup

OpenClaw manages container lifecycle — containers are removed when sessions end. Traefik route configs left behind are harmless.

Environment Variables

Static (set in openclaw.json sandbox.docker.env)

Dynamic (built by entrypoint, available in all shells)

Ports

Browser

The devbox agent has browser access via Chromium CDP (port 9222). The subagent can use the browser tool to navigate, screenshot, and interact with apps running inside the container (use http://localhost:{port}).

Project Setup Scripts

Projects can include .openclaw/setup.sh that runs inside the devbox. It has access to all env vars (APP_URL_*, APP_PORT_*, DEVBOX_ID, etc.) via /etc/profile.d/devbox.sh.

See references/setup-script-guide.md for conventions.