Review finding: callers mutate the returned dicts in place —
hermes_cli/web_server.py annotates s['enabled']/s['usage'] on the skills
list — so handing out the cached objects poisons the cache for every
subsequent caller (and is a cross-thread shared-mutable hazard in the
gateway). Return [dict(s) for s in cached] on both hit and miss paths;
warm-path cost is negligible (241x speedup retained on a 300-skill
fixture). Regression test mutates a returned list/dict and asserts the
next cached call is clean.
Review findings on the cherry-picked cache (follow-up to #58985):
- The cache key was the max mtime of only the TOP-LEVEL scan dirs.
Adding/removing a skill inside a category subdir bumps the category
dir's mtime, NOT the root's, so the cache served a stale list
indefinitely. Replace with a per-dir signature covering roots +
immediate children (one scandir per dir; mirrors
hermes_cli/profiles.py::_count_skills from d5eee133e).
- The disabled-set is config-driven and changes with no filesystem
mtime bump; fold it into the signature so /skills disable takes
effect without a restart.
- Platform is part of the signature (gateway processes serve multiple
platform scopes; scan results are platform-filtered).
- Add a 30s TTL to bound staleness from in-place SKILL.md edits (file
mtime is invisible to any directory signature).
- The original also keyed dirs off the module-level SKILLS_DIR constant;
the scan itself uses _skills_dir() (live profile HERMES_HOME) — use
the same resolution for the signature.
Mutation-verified: nested-add, disabled-set, and TTL tests fail against
the pre-fix cache and pass with it.
