docs(adr-0178-gb3b): scope referent-aware accumulation chaining (#464)

Grounded scope for GB-3b, the next Gap B move. Measured opportunity: 46/150
additive practice cases are sum-of-all==gold, all currently refusing, all the
single-referent accumulation shape ('X has N. He buys M more.' -> N+M). They
refuse correctly (GB-3a's multi-clause guard / the Alice+Bob hazard); the safe
ones differ by referent identity + a change-verb cue, which GB-3b reads.

Scope covers: the reading (anchor + change steps), the wrong=0-critical referent
model (minimal no-new-actor guard; cross-references ADR-0164.2/.3 + ADR-0174's
multi-actor hazard; deliberately does NOT resurrect the retired gender-blind
resolver), the proof-carrying wrong=0 obligations, the cue-precision coupling
(change cues should finally be reliable, closing CP-2a), the increments, and
honest flip expectations (big chunk in practice-additive; modest train_sample;
serving stays 3/47/0 until ratification).

docs/decisions/ADR-0178-GB3b-referent-accumulation-scope.md

@@ -0,0 +1,172 @@
+# ADR-0178 GB-3b — referent-aware accumulation chaining (scope)
+
+**Status:** Proposed (scope only — no code). Sub-phase of
+[ADR-0178](./ADR-0178-compositional-structure.md) Gap B. Builds on the GB-3a
+referent guard (PR #456) and the CP-2a measurement (PR #461).
+
+> **One-line thesis.** The first cross-clause reading that produces *flips in a
+> chunk* and is genuinely "comprehension": a single actor's quantity changes over
+> successive clauses (`X has N. He buys M more.` → `N + M`). The win is gated by a
+> tight referent + change-cue model so the Alice/Bob hazard still refuses.
+
+---
+
+## 1. The measured opportunity (why this is the next move, not a guess)
+
+Run on the 200 sealed cases (50 `train_sample` + 150 ADR-0163-F additive practice),
+deterministic:
+
+| lane | single product/sum == gold | needs multi-step |
+|------|---------------------------:|-----------------:|
+| `train_sample` | 2 / 50 | 48 |
+| `practice-additive` | **46 / 150 (`sum-of-all == gold`)** | — |
+
+All **46** additive cases are the *same shape* and **all currently refuse**
+(`practice` lane solves `0/150`). Inspected, every one is **single-referent
+accumulation**:
+
+```
+Sam has 14 apples. He buys 9 more. How many apples does Sam have now?   -> 14 + 9 = 23
+Lisa has 30 coins. She earns 15 more by doing chores. How many...?      -> 30 + 15 = 45
+Kate has 18 pencils. Her teacher gives her 5 more. How many...?         -> 18 + 5 = 23
+```
+
+The CP-2a measurement (PR #461) showed **no cue is reliable** because the blunt
+search's readings are crude. GB-3b is the *better candidate generation* that
+measurement said was the real lever — and the 46 cases are the concrete, gold-
+verified chunk it should flip. The subtract analog (`has N`, `gives/loses/uses M`)
+is the same shape and adds a comparable second chunk.
+
+## 2. Why they refuse now — and why that is *correct*
+
+GB-3a made `compose_sequential` refuse **all** multi-clause same-unit aggregation,
+to kill the referent hazards H1/H2/H3 (`Alice has 6 apples. Tom has 2 apples.` must
+not sum to Alice's total). These 46 cases **are multi-clause**, so GB-3a refuses
+them — correctly, given what it can currently see.
+
+The difference between a **safe** accumulation and the **hazard** is exactly two
+readable things:
+
+| | clause 2 | safe? |
+|---|---|---|
+| accumulation | `He buys 9 more` — *same actor* (pronoun), *change verb* | ✅ `+9` |
+| hazard (H1) | `Tom has 2 apples` — *new actor*, no change verb | ❌ refuse |
+
+GB-3b adds precisely this discrimination: **chain across clauses iff (same
+referent) ∧ (a licensed change cue); otherwise refuse.** It *generalises* GB-3a
+(refuse-all-multi-clause → chain-when-licensed-else-refuse), it does not weaken it.
+
+## 3. The reading GB-3b adds
+
+1. **Anchor.** The running total is clause 1's resolved GB-1 leaf: `(actor, N, unit)`.
+2. **Change steps.** Each later clause that (a) is **same-referent** and (b) carries
+   a **change cue** applies `± M` to the running total, where `M` is that clause's
+   grounded quantity. Op + polarity come from the cue lexeme; the operand from the
+   clause's text quantity; the order from clause order.
+3. **Gate.** The constructed chain runs through the unchanged self-verification gate
+   (grounding ∧ cue ∧ unit ∧ completeness ∧ uniqueness). The gate already keeps
+   wrong=0; GB-3b only proposes a *structurally licensed* candidate for it to verify.
+
+**Closed change-cue lexeme sets** (ADR-0165-safe — lexemes, not grammar templates;
+refined by the CP ledger, not asserted complete):
+
+- **GAIN (`+`)**: `buys, bought, gets, gments?` → `gets, got, receives, received,
+  finds, found, earns, earned, adds, added, gains, gained, makes, made, picks, more`
+- **LOSS (`−`)**: `gives, gave, loses, lost, spends, spent, uses, used, eats, ate,
+  sells, sold, drops, dropped, removes, removed, fewer, less`
+
+(Final sets curated against the corpus; an unknown change verb → refuse, never guess.)
+
+## 4. Referent model (wrong=0-critical) — cross-reference + decision
+
+**Prior art (must not reinvent):** `ADR-0164.2` (pronoun-entity-resolution),
+`ADR-0164.3` (cross-sentence-state), and `ADR-0174` (`PronounResolution` in
+`generate/math_candidate_graph.py`, with the **multi-actor pronoun hazard** —
+gender-blind most-recent-antecedent — recorded in memory
+`project-adr-0174-multi-actor-pronoun-hazard`). That comprehension subsystem is
+heavyweight, **did not move GSM8K scoring**, and was partly retired (`generate/
+comprehension/lifecycle.py` is dual-use/inert in scoring per `project-lifecycle-
+reader-dual-use`).
+
+**Decision:** GB-3b builds a **minimal, refuse-preferring referent guard in the
+derivation lane** — it does **not** resurrect the retired reader and does **not**
+reuse the gender-blind antecedent resolver (itself a hazard). Rationale: the clean
+derivation lane is what has been making progress; the old resolver's failure mode
+is exactly the multi-actor confusion we must refuse on.
+
+**The guard (lexeme/orthographic-anchored):**
+
+- Clause 1's **subject** = its leading proper noun (a capitalised token that is not
+  sentence-initial-only) or pronoun.
+- A later clause is **same-referent** iff it introduces **no new proper-noun actor**
+  — i.e. it continues via a pronoun (`He/She/They/Her/His`) or states no new named
+  subject.
+- If a later clause introduces a **different** proper-noun actor → **multi-actor →
+  refuse** (defensive; this is the ADR-0174 hazard's required fix, finally built).
+
+This is deliberately conservative: it refuses on any referent ambiguity rather than
+resolving it. Pronoun *gender/number* matching is **not** attempted (that was the
+old resolver's trap); "a new name appeared" is the only signal, and it triggers
+refusal, not resolution.
+
+## 5. wrong=0 obligations (must be *proven*, not asserted)
+
+A test must **fail** if any of these is violated (CLAUDE.md proof-obligation rule):
+
+1. **Grounded + cue-licensed + unit-consistent** change steps (the existing gate).
+2. **Multi-actor → refuse.** H1 (`Alice … Tom …`) stays `None`. A new proper-noun
+   subject in any clause refuses the whole chain.
+3. **No change cue → refuse.** Two clauses with quantities but no gain/loss lexeme
+   do not get summed (no implicit aggregation).
+4. **Ambiguous polarity → refuse.** A clause carrying both a gain and a loss lexeme,
+   or an unknown verb where a change is implied, refuses.
+5. **Comparative bound elsewhere (H2) → refuse**; **question-temporal-scope (H3,
+   "how many before giving any away") → refuse** (handling "before/after" question
+   scoping is deferred to a later increment; until then it must refuse, never apply
+   the change blindly).
+6. **Determinism**, **seal** (no `chat/` import), **serving `3/47/0`** byte-identical
+   (sealed substrate until a Phase-5 ratification, as with GB-3a/CP).
+
+## 6. Cue-precision coupling (this is what closes the CP-2a loop)
+
+CP-2a measured every existing cue at ~0.0 reliability. The change cues GB-3b
+introduces are structurally different: `buys` **always** adds, `gives` **always**
+subtracts — they should record **high** reliability in the CP ledger once GB-3b's
+candidates are trained through CP-2a. **GB-3b is the phase that finally produces a
+reliable cue pattern**, which is the prerequisite CP-2b (trust) was blocked on.
+The two tracks compound here: structure produces clean readings → cue-precision
+finds signal → trust becomes possible.
+
+## 7. Increments (one PR each, sealed, measured gold-checked)
+
+- **GB-3b.1 — single-referent gain/loss accumulation.** The anchor + one-or-more
+  change steps + the minimal referent guard (incl. pronoun-continuation, since the
+  46 use `He/She`). Flips the 46 additive `+` cases and the subtract analog.
+  **This is the chunk.**
+- **GB-3b.2 — multi-step / mixed accumulation.** 3+ changes, gain and loss in one
+  problem; running total across several clauses.
+- **GB-3b.3 — question-temporal scope.** "before/after he gave any away" — refuse-
+  aware reading of the *question's* time reference (closes H3 properly).
+
+## 8. Honest flip expectation (so we are not surprised)
+
+- **Big chunk in `practice-additive`**: GB-3b.1 should take the additive lane from
+  `0` correct toward `~46` (the `+` cases) and, with the subtract analog, a
+  comparable additional set — the first time the comprehension reading visibly
+  *works at scale*. **This is the progress signal**, measured and gold-checked.
+- **Modest in `train_sample`**: real GSM8K skews to multi-step *mixed*-operation
+  problems (48/50 need >1 op); single-referent accumulation will flip only the few
+  that are pure accumulation. GB-3b is the **foundational primitive** the multi-step
+  work composes on, not a one-shot GSM8K solve.
+- **Serving stays `3/47/0`** (sealed). Progress shows as practice `correct` rising
+  with `wrong` held at 0 (or eliminations only) — the two-regime contract.
+
+## 9. Acceptance (Proposed → Accepted)
+
+1. GB-3b.1 lands; the 46 `+` cases (and the subtract analog) flip to `correct` in
+   the practice lane under self-verification; `wrong` does not rise; serving frozen.
+2. The §5 obligations each have a test that fails under the violation (multi-actor
+   admitted, unlicensed/absent change summed, wrong polarity, H1/H2/H3).
+3. Change cues record measurable reliability in the CP ledger (CP-2a report),
+   demonstrating the structure→precision coupling of §6.
+4. Determinism/seal invariants hold; the GB-3a hazards H1/H2/H3 remain refused.

docs/decisions/ADR-0178-compositional-structure.md

@@ -146,10 +146,16 @@ gated wrong=0-first and measured honestly.
     clause refuses. This is the wrong=0-first floor (`compose_sequential` is sealed
     substrate, not yet wired to a scorer, so serving stayed `3/47/0`); tests in
     `tests/test_adr_0178_gb3_referent_guard.py` would fail against the pre-guard code.
-  - **GB-3b — constructive cross-clause chaining (next).** Consume GB-1
-    `ClauseResult`s and combine across clauses *referent-safely* (the chainer GB-2
-    was originally scoped to be), with lookback revising an earlier choice. Builds on
-    the now-safe GB-3a floor.
+  - **GB-3b — referent-aware accumulation chaining (scoped).** Consume GB-1
+    `ClauseResult`s and combine across clauses *referent-safely*: the first reading
+    is **single-referent accumulation** (`X has N. He buys M more.` → `N ± M`),
+    licensed by a closed change-verb cue set + a minimal "no new actor" referent
+    guard (generalises GB-3a: chain-when-licensed rather than refuse-all-multi-clause).
+    Measured target: the **46 `sum-of-all == gold` additive practice cases** (all
+    currently refusing) + the subtract analog — the first chunk where comprehension
+    visibly flips at scale. Full scope, cross-references (ADR-0164.2/.3, ADR-0174
+    multi-actor hazard), wrong=0 obligations, and increments in
+    [ADR-0178-GB3b-referent-accumulation-scope.md](./ADR-0178-GB3b-referent-accumulation-scope.md).
 - **GB-4 — held structural hypotheses + eliminate** (repoint `eliminate_violating` /
   `contemplate`): hold >1 structure on ambiguity, eliminate downstream, refuse if
   irreducible.