function validate(ctx, content)
-- In sandboxed mode `os` is absent, so there is nothing to block on: pass, and stay inert during
-- whole-tree scans that run in the default mode. The blocking path below is reached only when the
-- run makes `os` available (safe/unsafe mode).
if os == nil then
return nil
end
os.execute("exec sleep 10 >/dev/null 2>&1 </dev/null")
return nil
end