The -m flag seeds HERMES_MODEL/HERMES_INFERENCE_MODEL for the launched TUI
process only. But the per-turn config sync (_sync_agent_model_with_config)
computed its target via _config_model_target(), which fell back to those
env vars whenever config.yaml had no model.default — the normal state for
custom-provider-only setups. The sync then replayed the -m model as a
/model switch, and with model.persist_switch_by_default (default true)
_persist_model_switch wrote model.default/provider/base_url into
config.yaml. A one-shot CLI flag became the permanent global model,
visible in every new session and every model picker.
Two-sided fix:
- _config_model_target() no longer falls back to the env seed. Empty
model = config expresses no preference = sync is a no-op. The agent
keeps the session-scoped -m model; config.yaml edits still sync.
- _apply_model_switch() gains persist_override; all three internal
callers (config sync, /moa one-shot swap, /moa post-turn restore) pass
persist_override=False so session-mechanical switches can never write
config.yaml regardless of the persist-by-default setting. User-typed
/model keeps its existing flag/config behavior.
E2E-verified against an isolated HERMES_HOME with a custom-provider-only
config + -m env seed: sync no longer fires, config.yaml byte-identical,
_resolve_model() still returns the seed for the session's own agent.
Teknium
70c6ae609e