molecule_runtime's _deep_merge_hooks() uses unconditional list.extend()
when merging plugin settings-fragment.json files. On every plugin install
or reinstall each hook handler is re-appended, causing 3-4x duplicate
firings per event.
scripts/dedup_settings_hooks.py — idempotent live fix (reads via
/proc/*/root, no docker CLI required). Safe to re-run.
scripts/verify_settings_hooks.py — exits 1 if any container still has
duplicate hooks; used in CI health checks and manual audits.
Upstream fix needed in molecule_runtime._deep_merge_hooks() to
deduplicate by (matcher, frozenset(commands)) before writing. Track
separately.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
