The mechanism behind RISK-F-0003 was sharper than the finding described.
is_high_risk was risk == "high", but risk was never absent at the model layer:
RouteEntry.risk carried a dataclass default of "standard". An omitted grade was
not unhandled, it was actively resolved to the permissive value — fail-open by
construction, which is why nothing ever warned.
The default is now "ungraded" and is_high_risk returns true for anything outside
an explicit low-risk vocabulary (standard / low / accepted). An omitted grade and
an unrecognised grade from a newer catalog both resolve to high, so the boundary
fails safe in both directions rather than reading an unknown value as permission.
test_every_repo_catalog_lane_is_explicitly_graded is the CI gate that stops an
ungraded lane being committed, per ADR-0007: absence is not a grade.
"accepted" is in the low-risk vocabulary deliberately, ready for the
maturity-derived default — an experimental-context lane may be explicitly
accepted, which is a graded decision rather than an omission.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>