Sibling to ADR-0048's DEFINITION/RECALL pack-grounded surface for
the COMPARISON intent. `pack_grounded_comparison_surface(a, b)` in
`chat/pack_grounding.py` composes a deterministic side-by-side
surface from both lemmas' pack `semantic_domains`, joined by the
fixed connective "contrasts with":
"{a} (d_a1; d_a2) contrasts with {b} (d_b1; d_b2) — pack-grounded
({pack_id}). No session evidence yet."
`chat/runtime.py:_maybe_pack_grounded_surface` gains a COMPARISON
branch that runs before the DEFINITION/RECALL check. Engages only
when both `intent.subject` and `intent.secondary_subject` are pack
lemmas and differ (identical-lemma comparison defers to disclosure).
Order-sensitive by design — matches the graph-layer's directional
CONTRAST edge.
Cognition eval (13-case public split):
surface_groundedness 61.5% → 69.2% (+7.7 pp)
term_capture_rate 50.0% → 58.3% (+8.3 pp)
intent_accuracy 100.0% (=)
versor_closure_rate 100.0% (=)
Case lifted: comparison_memory_recall_030 ("Compare memory and
recall"). Remaining unlift cases (CAUSE×2, VERIFICATION×1,
CORRECTION×1) need teaching-store chains or operator-driven
inference — pack lookup cannot supply causal explanations,
verifications, or corrections without fabrication.
Tests: tests/test_pack_grounded_comparison.py (15 tests).
Lanes green: smoke (67), cognition (121), runtime (19), algebra
(132), teaching (17), packs (6).
Closes the surface-grounding gap isolated by ADR-0047's
characterisation. Adds the ratified cognition pack as a second
grounding source alongside the session vault.
== chat/pack_grounding.py (new) ==
Loads en_core_cognition_v1's lexicon once (cached; immutable pack)
and exposes:
pack_grounded_surface(lemma) -> str | None
Returns a deterministic, fully pack-sourced surface:
"{lemma} — pack-grounded ({pack_id}): {d1}; {d2}; {d3}. No session evidence yet."
Every visible atom is the lemma or a verbatim semantic_domains
string from the pack. No rewording, no synthesis, no LLM.
== chat/runtime.py ==
_stub_response gains optional pack_grounded_surface= parameter.
_maybe_pack_grounded_surface routes to the pack only when all four
hold: gate_source=="empty_vault", output_language=="en",
intent.tag in {DEFINITION, RECALL}, and intent.subject is a pack
lemma. Safety/ethics refusal still takes priority above this branch.
ChatResponse and TurnEvent gain grounding_source ∈ {vault,pack,none}.
Main walk path tags responses "vault".
== core/cognition/pipeline.py ==
gate_fired detection moved from string equality on the universal
disclosure to provenance:
gate_fired = response.vault_hits == 0 and response.grounding_source != "vault"
Same intent (suppress realizer template on gate-fired turns),
broader stub-path surface set.
== Characterisation (core eval cognition, 13-case public split) ==
Metric Pre Post Δ
intent_accuracy 100.0% 100.0% 0
surface_groundedness 15.4% 46.2% +30.8 pp
term_capture_rate 0.0% 33.3% +33.3 pp
versor_closure_rate 100.0% 100.0% 0
Lift is non-uniform by design: only single-lemma DEFINITION/RECALL
on pack-known English subjects engage. CAUSE/COMPARISON/VERIFICATION
and multi-word OOV subjects still return the universal disclosure —
fabricating those would violate the no-LLM-fallback doctrine.
== Tests ==
tests/test_pack_grounding.py 18 passed
tests/test_semantic_realizer_integration.py (updated) 1 stub-path test
pinned to the broader contract: surface is either universal
disclosure or pack-grounded; never the realizer template.
== Lanes ==
smoke 67 cognition 121 runtime 19 algebra 132
teaching 17 packs 6
versor_condition(F) < 1e-6 invariant unaffected (no algebra changes).
