Replaces the flat "I don't know — insufficient grounding" disclosure
with a deterministic gradient that names specific vocabulary gaps
and gives operators concrete next steps.
P2.1 — OOV "teach me" surface (chat/oov_surface.py).
When the intent classifier extracts a clean subject lemma but that
lemma is not resident in any mounted lexicon pack, the runtime now
emits a deterministic learning-invitation surface tagged
``grounding_source="oov"`` instead of the universal disclosure.
Surface format (fixed template):
"I haven't learned '{token}' yet (intent: {intent}).
Mounted lexicon packs: {pack_list}.
Teach me via a reviewed PackMutationProposal."
The OOV token passes through ``core._safe_display.safe_display``
before persistence — user-input sanitization at the trust boundary.
No vocabulary is invented; no domain is inferred. Honours the
ADR-0027 proposal-only invariant: the surface invites a reviewed
pack mutation, never silently mutates any pack.
Refactored ``_maybe_pack_grounded_surface`` so every existing
intent branch (COMPARISON / CAUSE / VERIFICATION / CORRECTION /
PROCEDURE / DEFINITION+RECALL) falls through on a None composer
result instead of early-returning. The OOV invitation is the
deterministic fall-through for any clean-subject prompt whose
subject doesn't resolve.
P2.2 — Partial-grounding tier (chat/partial_surface.py).
When exactly one of two COMPARISON lemmas resolves, the runtime
emits a hedged surface that grounds the known side verbatim and
disclaims the OOV side explicitly:
"Whatever '{oov}' is, I can ground '{known}' — pack-grounded
({pack_id}): {d1}; {d2}. I cannot ground the comparison
without learning '{oov}' — teach me via a reviewed
PackMutationProposal."
Tagged ``grounding_source="partial"``. Falls through to OOV
invitation when both lemmas are OOV, and to full pack-grounded
COMPARISON when both resolve — partial is the middle tier in the
five-tier gradient.
Also normalises trailing sentence punctuation on
intent.secondary_subject at the COMPARISON boundary so prompts
like "Compare A and B." (with the period) still resolve B
correctly.
Five-tier gradient (vault → teaching → pack → partial → oov → none).
Test debt retired: four pre-existing tests asserted "OOV → universal
disclosure", which is exactly the contract P2.1/P2.2 inverted.
Rewritten to the new contract. Plus test_procedure_surface.py
gained a test for the OOV gradient on procedure intents.
Verification:
tests/test_oov_surface.py 22 passed
tests/test_partial_surface.py 16 passed
Cognition eval byte-identical:
public 100% / 100% / 91.7% / 100%
holdout 100% / 100% / 83.3% / 100%
Curated lanes all green.
