Policy carries an operator-declared model_capabilities directory
and per-tier requires (tool_calling/reasoning/vision booleans,
min_context_tokens). decide_routing checks the policy tier model
in active mode: capable applies, incapable falls back to a capable
worker default, and if both fail or are unknown it returns
capability_blocked, which the worker turns into a failed task
(v3 tools-gate shape, runner never called). Shadow mode only
annotates the reason, never blocks. Explicit task and worker CLI
models bypass the check by design. Invalid requires drops only
that tier (fail-closed, like invalid tier mode). Dry-run reports
per-tier capability status and blocks on active tiers that fail
or cannot be verified.
RoutingPolicy gains tier_modes: a tier entry may be a string
(model, mode inherits global) or {model, mode}. The explicit
tier mode overrides the global mode in both directions, so plan
can be active while goal/default stay shadow, and one tier can
be rolled back to off without touching the others. An invalid
tier mode drops that tier entirely (fail-closed: a typo must
never accidentally activate a tier, and never kills other
tiers). Tier-off tasks return worker_default and are not
audited as policy/shadow, so they never inflate shadow sample
counts. Explicit task and worker-CLI models still win over any
tier mode.
Tests: test_routing_tier.py (5 tests).
Pre-dispatch routing only fills in tasks with no explicit model,
classified by structural signals only (plan > goal > default).
Explicit task model and worker CLI --model win over policy;
policy via CLOUD_ROUTING_POLICY_JSON/FILE + CLOUD_ROUTING_MODE.
Shadow mode records a suggestion without changing dispatch.
Only policy/shadow decisions emit a model_routing event, so the
existing events contract (fallback tests) is unchanged.
Fallback rules, effort/approval/sandbox/quota and provider are
untouched. Tests: test_models_routing.py (20 tests).
host