CORE now decides natural-English deductive arguments end-to-end:
'If it rains then the ground is wet. It rains. Therefore the ground
is wet.' -> ENTAILED, rendered over the user's own clauses. Both of
ADR-0256's documented boundary cases (multiword conditional, nested-
negation contraposition) are now decided; their lane gold updated
declined->entailed.
- generate/proof_chain/english.py (new): closed function-word grammar
over OPAQUE clause-atoms (minted ids); if/then, [either] or, and,
three negation forms (leading not / sentential / copular incl.
contractions); typed refusals; honesty caps. Soundness: positive
verdicts are substitution-closed; UNKNOWN is scoped + guarded
(quantifier-led, is-a membership, unnormalizable negation refuse
out of the opaque band).
- render_entailment_english: verdicts quoted back verbatim; UNKNOWN
phrasing explicitly scoped to the opaque reading.
- chat/deduction_surface.py: v2-EN fallback tier AFTER v1/v1b —
monotone widening, byte-identical on previously-served arguments.
- Four en_* shape-bands EARN SERVE via the ADR-0199 arena (720/band,
wrong=0, reliability 0.99087 >= 0.99); 9-band ledger re-sealed.
- evals/deduction_serve/v2_en: 26 hand-authored real-English cases
(content disjoint from the synthetic lexicon), wrong=0; report
re-pinned.
- realizer guard (ADR-0075): deduction surfaces exempt — quoted
templates are not slot-composed articulations (pack 'open'=VERB
was rejecting an honest quoted 'the door is not open'); pinned
cold+warm in e2e.
[Verification]: deductive 84 passed; smoke 180 passed; cognition 122
passed 1 skipped; arena 9x720 wrong=0 all SERVE; lanes v1 28/28,
v2_en 26/26.
Pins the arc's original goal against the ACTUAL serving spine (ChatRuntime,
the driver core chat constructs), not just the composer: a user asks a basic
logic question -> CORE decides -> an articulated, deterministic, telemetered
response comes back. Covers propositional + categorical, flag-off byte-identity
across both bands, honest reader-refusal on out-of-regime input (INV-34), and
the peripheral-systems wiring.
Peripheral systems verified (nothing to build, all automatic): deduction
turns are well-formed served turns (turn_log grows, _context.turn advances)
so ADR-0255 discovery-yield counts them; they carry grounding_source=
'deduction' on ChatResponse + TurnEvent and an observable DispatchAttempt;
they emit no discovery candidates (decided answer, not a would-have-grounded
gap) so they lift the yield denominator without inflating the numerator.
Scope-out doc (docs/research/deduction-serve-arc-completion-and-scope-outs-
2026-07-23.md) records the whole arc + everything deliberately deferred with
rationale: multi-word English reader relaxation (risky, shared reader, its
own pass), multi-step proof recap (Phase-6 core_logos), accrue_realized_
knowledge default, ADR-0246 s3.7 (blocked on research evidence not wiring),
Tier-2 (waits for field reader), Hamiltonian compiler (eval-side), and the
GroundingSource enum registration.
New: tests/test_deduction_serve_e2e.py (5 tests through the real REPL path).
[Verification]: core test --suite deductive 50 passed; smoke 180 passed;
cognition 122 passed/1 skipped.
