Files
hermes-agent/hermes_cli
John Paul Soliva 55a8f42329 perf(profiles): the listing re-reads a profile's YAML only when that file has changed
`list_profiles()` parsed three YAML files per profile on every call — config.yaml through
`read_user_config_raw` ("no cache", by contract) plus profile.yaml and distribution.yaml through
`_load_yaml_dict`. It is the shared body of `GET /api/profiles` and `profiles.list`, which the Bots
roster polls every 5s per connection, so an idle machine re-parsed every profile's YAML twelve
times a minute to produce the same handful of strings.

config.yaml is the expensive one: the installer seeds it by copying the annotated template verbatim
(`cp cli-config.yaml.example config.yaml`), 119,268 bytes / 2,267 lines of mostly comments, for
`model.default` and `model.provider`.

Measured, 9 profiles, no gateway locks so the liveness path stays out of it: 16.1ms -> 1.6ms with
the installer template, 6.4ms -> 1.6ms hand-trimmed; 27 YAML parses per pass -> 2, and those two
are the default profile's ABSENT files, correctly not cached. The pass is now independent of config
size.

The memo keys on each file's (mtime_ns, size, inode) — the atomic writers rename a temp file into
place, so a rewrite always lands a new inode even inside one mtime tick — and caches only the small
DERIVED values. `read_user_config_raw` and `_load_yaml_dict` keep their uncached contract: callers
write those documents back, and a stale read there could overwrite a newer file. `read_profile_meta`
hands out a copy so a future mutating caller cannot poison the next reader.

Regressions drive the real readers: an edited config/profile/distribution file is seen on the very
next read, `write_profile_meta` round-trips, a missing file is not cached and is picked up when
created, mutating a returned meta does not poison the next reader, an unchanged file is parsed once
across three reads, and `read_user_config_raw` still re-reads. Ignoring the signature fails four.

Fixes #117378
2026-09-20 18:45:07 -07:00
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