$ sbx exec m101-policy sh -c 'curl -sS --max-time 10 -I https://example.com; echo exit=$?'
HTTP/1.1 200 OK

HTTP/1.1 403 Forbidden
Content-Length: 90
Content-Type: text/plain

exit=0
[exit 0]

$ sbx exec m101-policy sh -c 'curl -sS --max-time 10 https://example.com; echo; echo exit=$?'
Approval required for example.com:443.

Review and respond with:
  sbx policy approval ls

exit=0
[exit 0]