check_all_command_guards() swallowed ImportError from tools.tirith_security
with an unconditional pass, leaving tirith_result["action"] as "allow"
regardless of security.tirith_fail_open. When an operator sets
tirith_fail_open: false they have explicitly opted into fail-closed
behaviour; a missing or broken Tirith module must not silently permit
command execution.
Inside the except ImportError handler, read the live security config.
When tirith_enabled is true and tirith_fail_open is false, synthesise a
"warn"-action Tirith result so the command flows through the normal
approval path (prompt the user, or block in cron/gateway contexts)
instead of bypassing it. The default tirith_fail_open: true behaviour
is unchanged.
Adds three regression tests to tests/tools/test_approval.py:
- fail_open=true + ImportError → silently allowed (no regression)
- fail_open=false + ImportError → approval callback invoked, command denied
- tirith_enabled=false → always allowed regardless of fail_open
Fixes#20733
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
# Conflicts:
# tests/tools/test_approval.py
Brandon Zarnitz
9c81c938d3