sandbox_exec

Sandbox Executor Skill

Trigger

Use this skill when the task requires executing commands in an isolated sandbox environment, or when managing workspace files.

Capabilities

• Acquire and release sandbox leases from the Foundry sandbox pool
• Execute shell commands inside the sandbox container
• Write files to the sandbox workspace via API
• Monitor command output and detect success/failure

API Reference

Acquire a sandbox lease

POST {SANDBOX_DAEMON_URL}/acquire
Content-Type: application/json
x-sandbox-token: {token}

{"username": "<agent_username>"}

Returns: {"lease_id": "...", "slot": 1, ...}

Execute a command

POST {SANDBOX_DAEMON_URL}/leases/{lease_id}/terminal/exec
Content-Type: application/json

{"command": "<shell_command>"}

Returns: Terminal output

Write a file to workspace

PUT {SANDBOX_DAEMON_URL}/users/{username}/workspace/write
Content-Type: application/json
x-sandbox-token: {token}

{"path": "relative/path/to/file.txt", "content": "file content here"}

List workspace files

GET {SANDBOX_DAEMON_URL}/users/{username}/workspace/tree
x-sandbox-token: {token}

Release the sandbox

POST {SANDBOX_DAEMON_URL}/release
Content-Type: application/json

{"lease_id": "<lease_id>"}

Best Practices

• Always release the sandbox lease after use (even on error — use try/finally)
• Wait 3-5 seconds after sandbox acquisition for container initialization
• Use unique markers in commands to detect success: echo EXIT_CODE=$?
• Set reasonable timeouts for long-running commands: timeout 30 <command>
• Check pool status before acquiring: GET /pool-status

Environment Variables

• SANDBOX_DAEMON_URL: Daemon endpoint (default: http://localhost:9000)
• SANDBOX_TOKEN: Authentication token for the daemon API

Error Handling

• If lease acquisition fails, the pool may be full — retry after delay
• If command execution times out, the sandbox may need to be released and re-acquired
• Always check HTTP status codes: 200/201 = success, 4xx = client error, 5xx = server error