Tests collapse 13 change-detectors into 7 invariants (silent below threshold /
without context, fires above, same-model re-select silent, config override and
0-disables, registry threading, agent context derivation). The legacy 5-arg
guard test goes with the TypeError fallback it covered: that fallback was
defence for a case nobody has (every in-tree guard and test double is
*args-tolerant) and would re-run a guard whose real TypeError it masked, so the
rebased port passes the context positionally like every other argument.
Docs no longer claim the confirm fires on the Telegram/Discord pickers or the
dashboard: those surfaces call combined_selection_warning() without a live
agent, so the context-cache guard is (correctly) silent there.
Providers key prompt caches per model, so a mid-session /model switch makes
the next reply re-read the entire conversation at full input price. deepagents
gates user-initiated switches behind a confirmation once the active thread
exceeds a configurable token threshold; this ports the same protection into
Hermes' unified selection-guard registry so it renders on every surface at
once (CLI/TUI picker, gateway /model, Telegram/Discord pickers, dashboard).
- hermes_cli/model_selection_guards.py: new context_cache guard +
SelectionContext carrier + selection_context_for_agent() helper;
registry threads live-session facts to guards (6-arg signature with a
TypeError fallback for externally patched 5-arg guards).
- config: model.switch_context_confirm_tokens (default 100000, 0 disables).
- cli.py / gateway/slash_commands.py / tui_gateway/server.py: thread the
live agent's measured context into the guard call.
- docs: configuring-models.md mid-session switch section.
- tests: tests/hermes_cli/test_context_cache_switch_guard.py (13 cases).
Adds hermes_cli/model_selection_guards.py: a single evaluation point that
runs every selection guard (cost + the new data-policy guard) and returns
the warnings that fired. All seven model-selection surfaces (CLI picker,
cli.py TUI modal, gateway typed /model, dashboard web_server, TUI gateway,
Telegram and Discord pickers) now call the registry instead of importing
model_cost_guard directly — so the data-training-tier warning from
PR #81416 fires everywhere at once, and future guards need zero surface
wiring.
Guard modules keep their public APIs; existing mock patch points
(hermes_cli.model_cost_guard.expensive_model_warning) remain valid.
