diff --git a/evals/capability_index/adapters.py b/evals/capability_index/adapters.py
index 24951dac..39ec7d8e 100644
--- a/evals/capability_index/adapters.py
+++ b/evals/capability_index/adapters.py
@@ -70,10 +70,19 @@ def comprehension_propositional_result() -> DomainResult:
     return DomainResult("comprehension_propositional", c, w, r)
 
 
+def comprehension_relational_metric_result() -> DomainResult:
+    from evals.comprehension.relational_metric_runner import run
+
+    c, w, r = _counts(run())
+    return DomainResult("comprehension_relational_metric", c, w, r)
+
+
 #: The reasoning domains currently composed into the index (self-loading lanes).
-#: The four ``comprehension_*`` lanes score the GENERAL comprehension reader
-#: (prose -> MeaningGraph -> projection -> independent oracle), so the index now
-#: measures comprehension breadth, not just structured-input reasoning.
+#: The five ``comprehension_*`` lanes score the GENERAL comprehension reader; the
+#: relational_metric one reads arithmetic prose into the binding-graph quantity
+#: substrate (admissibility-checked) and projects to the arithmetic oracle, so the
+#: index now measures comprehension breadth across categorical, ordering,
+#: propositional, AND quantitative reasoning.
 ADAPTERS = (
     deductive_logic_result,
     relational_metric_result,
@@ -82,6 +91,7 @@ ADAPTERS = (
     comprehension_syllogism_result,
     comprehension_total_ordering_result,
     comprehension_propositional_result,
+    comprehension_relational_metric_result,
 )
 
 
diff --git a/evals/capability_index/baseline.json b/evals/capability_index/baseline.json
index 34dad1bd..f2bc8be8 100644
--- a/evals/capability_index/baseline.json
+++ b/evals/capability_index/baseline.json
@@ -1,13 +1,13 @@
 {
-  "capability_score": 0.928622,
-  "coverage_geomean": 0.928622,
-  "coverage_micro": 0.993582,
+  "capability_score": 0.937258,
+  "coverage_geomean": 0.937258,
+  "coverage_micro": 0.993703,
   "accuracy_micro": 1.0,
-  "breadth": 7,
+  "breadth": 8,
   "min_domain_coverage": 0.833333,
   "wrong_total": 0,
   "assert_mode_valid": true,
-  "deterministic_digest": "51df7bba62a035c73bdaf289ea20cded05b66b2f7ca5fd8bbcb04f127d60cadf",
+  "deterministic_digest": "50e0675bd69938ce5747b5d47592504b9cf143027dd6c1c5e410da0add25341c",
   "domains": [
     {
       "domain": "comprehension_propositional",
@@ -17,6 +17,14 @@
       "coverage": 1.0,
       "accuracy": 1.0
     },
+    {
+      "domain": "comprehension_relational_metric",
+      "correct": 15,
+      "wrong": 0,
+      "refused": 0,
+      "coverage": 1.0,
+      "accuracy": 1.0
+    },
     {
       "domain": "comprehension_set_membership",
       "correct": 8,
diff --git a/evals/comprehension/relational_metric_runner.py b/evals/comprehension/relational_metric_runner.py
new file mode 100644
index 00000000..594c2d5b
--- /dev/null
+++ b/evals/comprehension/relational_metric_runner.py
@@ -0,0 +1,75 @@
+"""Score the general comprehension reader on the relational_metric gold lane.
+
+prose -> comprehend_quantitative() -> binding_graph -> to_relational_metric() ->
+independent arithmetic oracle -> answer vs gold. This is the binding-graph's first
+comprehension consumer: quantities live in the binding-graph (admissibility-checked,
+never stamped), then project to the relational_metric oracle for the verdict.
+
+A refusal (unreadable prose, admissibility refusal, unprojectable, or an
+OracleError on the projection) is NOT a wrong; only a committed integer answer that
+disagrees with gold is wrong (must stay 0).
+"""
+
+from __future__ import annotations
+
+import json
+import sys
+from typing import Any
+
+from evals.relational_metric.oracle import OracleError, oracle_answer
+from evals.relational_metric.runner import _load_cases
+from generate.meaning_graph.reader import Refusal
+from generate.quantitative_comprehension import comprehend_quantitative, to_relational_metric
+
+
+def run() -> dict[str, Any]:
+    cases = _load_cases()
+    correct = wrong = refused = 0
+    wrongs: list[dict[str, Any]] = []
+
+    for case in cases:
+        comp = comprehend_quantitative(case["text"])
+        if isinstance(comp, Refusal):
+            refused += 1
+            continue
+        projected = to_relational_metric(comp)
+        if projected is None:
+            refused += 1
+            continue
+        relations, query = projected
+        try:
+            got = oracle_answer(relations, query)
+        except OracleError:
+            refused += 1
+            continue
+        if got == case.get("gold"):
+            correct += 1
+        else:
+            wrong += 1
+            wrongs.append(
+                {"id": case.get("id"), "got": got, "gold": case.get("gold"), "text": case["text"]}
+            )
+
+    return {
+        "domain": "comprehension_relational_metric",
+        "total": len(cases),
+        "correct": correct,
+        "wrong": wrong,
+        "refused": refused,
+        "wrongs": wrongs,
+        "counts": {"correct": correct, "wrong": wrong, "refused": refused},
+    }
+
+
+def main() -> int:
+    report = run()
+    print(json.dumps({k: v for k, v in report.items() if k != "wrongs"}, indent=2, sort_keys=True))
+    if report["wrong"]:
+        print("WRONG > 0 — comprehension produced a wrong committed answer:", file=sys.stderr)
+        print(json.dumps(report["wrongs"], indent=2), file=sys.stderr)
+        return 1
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/generate/quantitative_comprehension.py b/generate/quantitative_comprehension.py
new file mode 100644
index 00000000..4ad14a63
--- /dev/null
+++ b/generate/quantitative_comprehension.py
@@ -0,0 +1,324 @@
+"""Arithmetic word-problem comprehension -> binding_graph (Phase 2b, domain 5).
+
+The doctrine-aligned quantity reader, and the binding-graph's FIRST comprehension
+consumer. Quantities live in the ``binding_graph`` substrate — CLAUDE.md: the
+``MeaningGraph`` deliberately excludes quantities — so this reader lives OUTSIDE
+``generate/meaning_graph`` (which stays a numeric-free interlingua, INV-28) and
+targets the binding-graph instead.
+
+It reads arithmetic prose ("Liam has 6 stickers. Mia has 4 more stickers than
+Liam.") into ``SymbolBinding`` / ``BoundFact`` / ``BoundEquation`` and runs the
+REAL ``check_admissibility`` — there is NO stamped "admitted": an equation is
+admitted only if its operand units actually verify, and a dimensional mismatch
+REFUSES the whole reading. ``to_relational_metric`` then projects the binding-graph
+into the independent ``relational_metric`` oracle for scoring.
+
+Templates (function-word + order; digits only — a non-digit quantity REFUSES):
+  - ``<X> has <N> <unit>``                 -> BoundFact(X = N [unit])
+  - ``<Y> has <N> more <unit> than <X>``   -> BoundEquation(Y = X + N)   op=add
+  - ``<Y> has <N> fewer <unit> than <X>``  -> BoundEquation(Y = X - N)   op=subtract
+  - query ``How many <unit> does <Y> have``       -> ask Y
+  - query ``How many <unit> do <X> and <Y> have`` -> total = X + Y; ask total
+
+Refusal-first: an unparseable clause, a non-digit quantity, a non-identifier name,
+a missing/duplicated query, or an admissibility refusal all return a typed
+``Refusal`` — never a fabricated quantity (wrong=0 at the comprehension layer).
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any
+
+from generate.binding_graph.admissibility import AdmissibilityError, check_admissibility
+from generate.binding_graph.model import (
+    BoundEquation,
+    BoundFact,
+    SemanticSymbolicBindingGraph,
+    SourceSpanLink,
+    SymbolBinding,
+)
+from generate.binding_graph.units import UnitAlgebraError, parse_unit
+from generate.meaning_graph.reader import Refusal, _split_sentences
+
+_INTRODUCED_BY = "comprehend_quantitative"
+
+#: The generic count dimension for discrete sortal objects (an existing pack
+#: lemma resolving to dimension ``count``). A noun the unit pack does not know is
+#: read as a count of discrete objects, NOT faked into a physical unit.
+_COUNT_UNIT = "item"
+
+
+def _resolve_unit(noun: str) -> str:
+    """Map a surface unit noun to a binding-graph unit the pack accepts.
+
+    A KNOWN physical/currency/count unit (``dollars`` -> ``dollar``, ``meters``)
+    is used verbatim (``parse_unit`` depluralizes). An UNKNOWN sortal noun
+    (``stickers``, ``coins``) is a count of discrete objects -> ``item`` (dimension
+    ``count``). This keeps admissibility a REAL check: ``count + count`` admits,
+    ``count + length`` still refuses — nothing is stamped or faked.
+    """
+    try:
+        parse_unit(noun)
+    except UnitAlgebraError:
+        return _COUNT_UNIT
+    return noun
+
+
+@dataclass(frozen=True, slots=True)
+class QuantQuery:
+    """The question over the comprehended quantities (which entity's count)."""
+
+    entity: str
+    unit: str
+    span: SourceSpanLink
+
+
+@dataclass(frozen=True, slots=True)
+class QuantComprehension:
+    """Successful arithmetic comprehension: a binding_graph + the asked entity."""
+
+    binding_graph: SemanticSymbolicBindingGraph
+    query: QuantQuery
+
+
+class _QReject(Exception):
+    """Internal: a clause matched a shape but is not honestly readable."""
+
+    def __init__(self, reason: str, detail: str = "") -> None:
+        super().__init__(reason)
+        self.refusal = Refusal(reason, detail)
+
+
+def _ident(tok: str, detail: str) -> str:
+    w = tok.strip().lower()
+    if not w.isidentifier():
+        raise _QReject("non_identifier_name", detail)
+    return w
+
+
+def _int(tok: str, detail: str) -> int:
+    if not tok.isdigit():
+        raise _QReject("non_digit_quantity", detail)
+    return int(tok)
+
+
+@dataclass(frozen=True, slots=True)
+class _Fact:
+    entity: str
+    value: int
+    unit: str
+
+
+@dataclass(frozen=True, slots=True)
+class _Eq:
+    entity: str
+    ref: str
+    delta: int
+    op: str  # "add" | "subtract"
+    unit: str
+
+
+def _parse_sentence(body: str, detail: str):
+    """Return a (_Fact | _Eq | ('query', entity, unit) | ('sumquery', parts, unit))
+    spec, or None if the sentence matches no arithmetic template."""
+    toks = body.strip().lower().rstrip("?.!").split()
+    if not toks:
+        return None
+
+    if len(toks) >= 5 and toks[0] == "how" and toks[1] == "many" and toks[-1] == "have":
+        unit = _resolve_unit(_ident(toks[2], detail))
+        rest = toks[3:-1]  # between "<unit>" and "have"
+        if rest and rest[0] == "does" and len(rest) == 2:
+            return ("query", _ident(rest[1], detail), unit)
+        if rest and rest[0] == "do":
+            parts = [_ident(t, detail) for t in rest[1:] if t != "and"]
+            if len(parts) >= 2:
+                return ("sumquery", tuple(parts), unit)
+        raise _QReject("unreadable_quantity_query", detail)
+
+    if len(toks) >= 4 and toks[1] == "has":
+        entity = _ident(toks[0], detail)
+        value = _int(toks[2], detail)
+        if len(toks) == 4:
+            return _Fact(entity, value, _resolve_unit(_ident(toks[3], detail)))
+        if len(toks) == 7 and toks[3] in ("more", "fewer") and toks[5] == "than":
+            op = "add" if toks[3] == "more" else "subtract"
+            return _Eq(
+                entity, _ident(toks[6], detail), value, op, _resolve_unit(_ident(toks[4], detail))
+            )
+        raise _QReject("unreadable_quantity_clause", detail)
+
+    return None
+
+
+def _span(text: str) -> SourceSpanLink:
+    return SourceSpanLink(source_id="input", start=0, end=max(1, len(text)), text=text or " ")
+
+
+def _rhs(op: str, ref: str, delta: int) -> str:
+    return f"{ref} + {delta}" if op == "add" else f"{ref} - {delta}"
+
+
+def comprehend_quantitative(text: str, source_id: str = "input") -> QuantComprehension | Refusal:
+    """Comprehend arithmetic prose into a binding_graph + asked entity, or refuse."""
+    if not text or not text.strip():
+        return Refusal("empty")
+    sentences = _split_sentences(text)
+    if not sentences:
+        return Refusal("empty")
+
+    facts: list[_Fact] = []
+    eqs: list[_Eq] = []
+    queries: list[tuple] = []
+
+    try:
+        for body, _terminator, _start, _end in sentences:
+            spec = _parse_sentence(body, body)
+            if spec is None:
+                return Refusal("no_quantity_template", body)
+            if isinstance(spec, _Fact):
+                facts.append(spec)
+            elif isinstance(spec, _Eq):
+                eqs.append(spec)
+            else:
+                queries.append(spec)
+    except _QReject as rej:
+        return rej.refusal
+
+    if len(queries) != 1 or not facts:
+        return Refusal("no_single_quantity_query")
+
+    unit_of: dict[str, str] = {}
+    role_of: dict[str, str] = {}
+    for f in facts:
+        unit_of[f.entity], role_of[f.entity] = f.unit, "count"
+    for e in eqs:
+        unit_of[e.entity], role_of[e.entity] = e.unit, "count"
+
+    query = queries[0]
+    sum_eq: tuple[str, tuple[str, ...]] | None = None
+    if query[0] == "query":
+        ask_entity, ask_unit = query[1], query[2]
+    else:  # sumquery -> synthesize a total symbol + sum equation
+        parts, ask_unit = query[1], query[2]
+        ask_entity = "total"
+        unit_of.setdefault(ask_entity, ask_unit)
+        role_of[ask_entity] = "total"
+        sum_eq = (ask_entity, parts)
+
+    referenced: set[str] = set()
+    for f in facts:
+        referenced.add(f.entity)
+    for e in eqs:
+        referenced.update((e.entity, e.ref))
+    if sum_eq is not None:
+        referenced.add(sum_eq[0])
+        referenced.update(sum_eq[1])
+    referenced.add(ask_entity)
+
+    symbols = [
+        SymbolBinding(
+            symbol_id=sid,
+            name=sid,
+            semantic_role=role_of.get(sid, "count"),
+            source_span=_span(sid),
+            introduced_by=_INTRODUCED_BY,
+            entity=sid,
+            unit=unit_of.get(sid),
+        )
+        for sid in sorted(referenced)
+    ]
+    symbols_by_id = {s.symbol_id: s for s in symbols}
+
+    bound_facts = tuple(
+        BoundFact(symbol_id=f.entity, value=str(f.value), source_span=_span(f.entity), unit=f.unit)
+        for f in facts
+    )
+
+    # equations: shell -> REAL admissibility -> rebuild (NEVER stamp "admitted").
+    eq_specs: list[tuple[str, str, frozenset[str], str]] = [
+        (e.entity, _rhs(e.op, e.ref, e.delta), frozenset({e.ref}), e.op) for e in eqs
+    ]
+    if sum_eq is not None:
+        lhs, parts = sum_eq
+        eq_specs.append((lhs, " + ".join(parts), frozenset(parts), "add"))
+
+    equations: list[BoundEquation] = []
+    for lhs, rhs, deps, op in eq_specs:
+        shell = BoundEquation(
+            lhs_symbol_id=lhs,
+            rhs_canonical=rhs,
+            dependencies=deps,
+            operation_kind=op,
+            unit_proof="pending",
+            admissibility_status="pending",
+            source_span=_span(lhs),
+        )
+        try:
+            proof = check_admissibility(shell, symbols=symbols_by_id)
+        except AdmissibilityError as exc:
+            return Refusal("admissibility_refused", f"{lhs}: {exc.reason}")
+        equations.append(
+            BoundEquation(
+                lhs_symbol_id=lhs,
+                rhs_canonical=rhs,
+                dependencies=deps,
+                operation_kind=op,
+                unit_proof=proof.to_canonical_string(),
+                admissibility_status="admitted",
+                source_span=_span(lhs),
+            )
+        )
+
+    try:
+        graph = SemanticSymbolicBindingGraph(
+            symbols=tuple(symbols), facts=bound_facts, equations=tuple(equations)
+        )
+    except Exception as exc:  # noqa: BLE001 — surface construction refusal
+        return Refusal("invalid_binding_graph", repr(exc))
+
+    return QuantComprehension(
+        binding_graph=graph,
+        query=QuantQuery(entity=ask_entity, unit=ask_unit, span=_span(ask_entity)),
+    )
+
+
+def to_relational_metric(
+    comp: QuantComprehension,
+) -> tuple[list[dict[str, Any]], dict[str, Any]] | None:
+    """Project the comprehended binding_graph into ``(relations, query)`` for
+    ``evals.relational_metric.oracle.oracle_answer``.
+
+    Reads the binding-graph itself (facts + admitted equations) — the equation's
+    own ``rhs_canonical`` is parsed back (a controlled round-trip of the format this
+    module emits) and operands are classified as symbol (a known entity) vs literal.
+    Facts are emitted before equations and equations in dependency order, so the
+    oracle's forward substitution never hits an unresolved reference.
+    """
+    graph = comp.binding_graph
+    symbol_ids = {s.symbol_id for s in graph.symbols}
+    relations: list[dict[str, Any]] = [
+        {"kind": "fact", "entity": f.symbol_id, "value": int(f.value)} for f in graph.facts
+    ]
+    for eq in graph.equations:
+        rhs = eq.rhs_canonical
+        if " + " in rhs:
+            operands = rhs.split(" + ")
+            if all(op in symbol_ids for op in operands):
+                relations.append({"kind": "sum_of", "entity": eq.lhs_symbol_id, "parts": list(operands)})
+                continue
+            ref, literal = operands[0], operands[1]
+            relations.append(
+                {"kind": "more_than", "entity": eq.lhs_symbol_id, "ref": ref, "delta": int(literal)}
+            )
+        elif " - " in rhs:
+            ref, literal = rhs.split(" - ")
+            relations.append(
+                {"kind": "fewer_than", "entity": eq.lhs_symbol_id, "ref": ref, "delta": int(literal)}
+            )
+        else:
+            return None  # unrecognized equation shape -> refuse
+    if not relations:
+        return None
+    return relations, {"entity": comp.query.entity, "unit": comp.query.unit}
diff --git a/tests/test_architectural_invariants.py b/tests/test_architectural_invariants.py
index f5885144..c89cff9e 100644
--- a/tests/test_architectural_invariants.py
+++ b/tests/test_architectural_invariants.py
@@ -1144,6 +1144,19 @@ INDEPENDENT_GOLD_LANES: tuple[IndependentGoldLane, ...] = (
         oracle_module="evals/deductive_logic/oracle.py",
         sut_import_prefixes=("generate.meaning_graph",),
     ),
+    # The arithmetic comprehension lane: the SUT is the quantity reader
+    # (generate.quantitative_comprehension) and the binding-graph substrate it
+    # builds. The relational_metric oracle (forward substitution) must share no code
+    # with either — the arithmetic gold stays independent of the reader.
+    IndependentGoldLane(
+        name="comprehension_relational_metric",
+        oracle_module="evals/relational_metric/oracle.py",
+        sut_import_prefixes=(
+            "generate.quantitative_comprehension",
+            "generate.binding_graph",
+            "generate.meaning_graph",
+        ),
+    ),
 )
 
 _DEDUCTIVE_CASE_FILES: tuple[str, ...] = (
diff --git a/tests/test_capability_index.py b/tests/test_capability_index.py
index 71195357..c044d1df 100644
--- a/tests/test_capability_index.py
+++ b/tests/test_capability_index.py
@@ -97,7 +97,7 @@ def test_real_lanes_compose_into_the_index_with_wrong_zero() -> None:
     idx = aggregate(list(collection.results))
     assert idx.wrong_total == 0
     assert idx.assert_mode_valid
-    assert idx.breadth == 7
+    assert idx.breadth == 8
     assert {d.domain for d in idx.domains} == {
         "deductive_logic",
         "dimensional",
@@ -106,6 +106,7 @@ def test_real_lanes_compose_into_the_index_with_wrong_zero() -> None:
         "comprehension_syllogism",
         "comprehension_total_ordering",
         "comprehension_propositional",
+        "comprehension_relational_metric",
     }
     assert idx.capability_score > 0.5  # real, non-trivial cross-domain capability
 
diff --git a/tests/test_comprehension_relational_metric.py b/tests/test_comprehension_relational_metric.py
new file mode 100644
index 00000000..31fdf3df
--- /dev/null
+++ b/tests/test_comprehension_relational_metric.py
@@ -0,0 +1,30 @@
+"""Phase 2b — end-to-end: the comprehension reader scored on relational_metric.
+
+prose -> comprehend_quantitative -> binding_graph -> to_relational_metric ->
+INDEPENDENT arithmetic oracle -> answer vs gold. The load-bearing invariant:
+wrong == 0. This is the binding-graph's first comprehension consumer; quantities
+are admissibility-checked (never stamped), then projected to the oracle.
+"""
+
+from __future__ import annotations
+
+from evals.comprehension.relational_metric_runner import run
+
+
+def test_comprehension_relational_metric_wrong_is_zero() -> None:
+    report = run()
+    assert report["wrong"] == 0, report["wrongs"]
+
+
+def test_comprehension_relational_metric_has_real_coverage() -> None:
+    report = run()
+    assert report["correct"] > 0
+    assert report["correct"] + report["refused"] == report["total"]
+
+
+def test_comprehension_relational_metric_full_coverage() -> None:
+    # The whole 15-case lane reads end-to-end (fact / more_than / fewer_than /
+    # sum_of, single + chained, count nouns -> item dimension, dollars -> money).
+    report = run()
+    assert report["refused"] == 0
+    assert report["correct"] == report["total"]
diff --git a/tests/test_comprehension_structure_preserving.py b/tests/test_comprehension_structure_preserving.py
index e51da491..45fea0a0 100644
--- a/tests/test_comprehension_structure_preserving.py
+++ b/tests/test_comprehension_structure_preserving.py
@@ -26,6 +26,7 @@ from generate.meaning_graph.projectors import (
     to_total_ordering,
 )
 from generate.meaning_graph.reader import Refusal, comprehend
+from generate.quantitative_comprehension import comprehend_quantitative, to_relational_metric
 
 _TERMS = [f"t{i}" for i in range(8)]
 
@@ -263,3 +264,42 @@ def test_propositional_invariant_to_premise_reorder() -> None:
     s_base = _struct(base, to_deductive_logic)
     assert s_base is not None
     assert _struct(swapped, to_deductive_logic) == s_base
+
+
+# --------------------------------------------------------------------------- #
+# Arithmetic (binding_graph) — projected relations + query preserved exactly.
+# --------------------------------------------------------------------------- #
+
+
+def test_arithmetic_structure_is_preserved_exactly() -> None:
+    rng = random.Random(55)
+    committed = 0
+    for _ in range(300):
+        ents = rng.sample([f"e{i}" for i in range(6)], rng.randint(2, 4))
+        base, base_val = ents[0], rng.randint(1, 20)
+        relations = [{"kind": "fact", "entity": base, "value": base_val}]
+        lines = [f"{base} has {base_val} things."]
+        prev = base
+        for e in ents[1:]:
+            delta = rng.randint(1, 15)
+            kind = rng.choice(["more_than", "fewer_than"])
+            word = "more" if kind == "more_than" else "fewer"
+            relations.append({"kind": kind, "entity": e, "ref": prev, "delta": delta})
+            lines.append(f"{e} has {delta} {word} things than {prev}.")
+            prev = e
+        ask = rng.choice(ents)
+        lines.append(f"How many things does {ask} have?")
+        prose = " ".join(lines)
+        expected_query = {"entity": ask, "unit": "item"}  # "things" -> item dimension
+
+        comp = comprehend_quantitative(prose)
+        if isinstance(comp, Refusal):
+            continue
+        proj = to_relational_metric(comp)
+        if proj is None:
+            continue
+        committed += 1
+        prelations, pquery = proj
+        assert _canon(prelations) == _canon(relations), (prose, prelations, relations)
+        assert pquery == expected_query, (prose, pquery, expected_query)
+    assert committed > 50
diff --git a/tests/test_quantitative_comprehension.py b/tests/test_quantitative_comprehension.py
new file mode 100644
index 00000000..be9e7958
--- /dev/null
+++ b/tests/test_quantitative_comprehension.py
@@ -0,0 +1,99 @@
+"""Unit tests for the arithmetic reader (prose -> binding_graph) + its projector.
+
+Pins the templates, the count-vs-physical-unit modelling, and — load-bearing — the
+REAL admissibility check: an equation is admitted only if its operand units verify,
+so a mixed-unit sum REFUSES rather than fabricating a quantity. This is the
+reviewer's "do not stamp admissibility" guard, made executable.
+"""
+
+from __future__ import annotations
+
+from generate.binding_graph.model import SemanticSymbolicBindingGraph
+from generate.meaning_graph.reader import Refusal
+from generate.quantitative_comprehension import (
+    QuantComprehension,
+    comprehend_quantitative,
+    to_relational_metric,
+)
+
+
+def _comp(text: str) -> QuantComprehension:
+    comp = comprehend_quantitative(text)
+    assert isinstance(comp, QuantComprehension), comp
+    return comp
+
+
+def test_fact_and_more_than_build_binding_graph() -> None:
+    comp = _comp("Liam has 6 stickers. Mia has 4 more stickers than Liam. How many stickers does Mia have?")
+    g = comp.binding_graph
+    assert isinstance(g, SemanticSymbolicBindingGraph)
+    assert {f.symbol_id: f.value for f in g.facts} == {"liam": "6"}
+    eq = next(e for e in g.equations if e.lhs_symbol_id == "mia")
+    assert eq.operation_kind == "add"
+    assert eq.rhs_canonical == "liam + 4"
+    assert eq.admissibility_status == "admitted"  # from the REAL check, not stamped
+    assert comp.query.entity == "mia"
+
+
+def test_count_nouns_resolve_to_item_dimension() -> None:
+    # Unknown sortal nouns become the count dimension (item); admissibility admits.
+    comp = _comp("Kim has 2 marbles. Leo has 3 more marbles than Kim. How many marbles does Leo have?")
+    units = {s.symbol_id: s.unit for s in comp.binding_graph.symbols}
+    assert units["kim"] == "item" and units["leo"] == "item"
+
+
+def test_known_unit_is_used_verbatim() -> None:
+    comp = _comp("Iris has 100 dollars. Jack has 250 more dollars than Iris. How many dollars does Jack have?")
+    units = {s.symbol_id: s.unit for s in comp.binding_graph.symbols}
+    assert units["iris"] == "dollars"  # parse_unit depluralizes dollars -> dollar (money)
+
+
+def test_fewer_than_is_subtract() -> None:
+    comp = _comp("Noah has 15 cards. Olivia has 6 fewer cards than Noah. How many cards does Olivia have?")
+    eq = next(e for e in comp.binding_graph.equations if e.lhs_symbol_id == "olivia")
+    assert eq.operation_kind == "subtract" and eq.rhs_canonical == "noah - 6"
+
+
+def test_sum_query_synthesizes_total() -> None:
+    comp = _comp("Dan has 7 coins. Eva has 9 more coins than Dan. How many coins do Dan and Eva have?")
+    assert comp.query.entity == "total"
+    total_eq = next(e for e in comp.binding_graph.equations if e.lhs_symbol_id == "total")
+    assert total_eq.operation_kind == "add"
+    assert set(total_eq.dependencies) == {"dan", "eva"}
+
+
+def test_projection_shape() -> None:
+    comp = _comp("Liam has 6 stickers. Mia has 4 more stickers than Liam. How many stickers does Mia have?")
+    projected = to_relational_metric(comp)
+    assert projected is not None
+    relations, query = projected
+    assert {"kind": "fact", "entity": "liam", "value": 6} in relations
+    assert {"kind": "more_than", "entity": "mia", "ref": "liam", "delta": 4} in relations
+    assert query["entity"] == "mia"
+
+
+# --------------------------------------------------------------------------- #
+# Admissibility is REAL, not stamped (the reviewer's load-bearing guard)
+# --------------------------------------------------------------------------- #
+
+
+def test_mixed_unit_sum_refuses_via_admissibility() -> None:
+    # count (stickers -> item) + money (dollars) cannot be summed: the REAL
+    # admissibility check must REFUSE, not fabricate a total.
+    comp = comprehend_quantitative(
+        "Liam has 6 stickers. Mia has 4 dollars. How many things do Liam and Mia have?"
+    )
+    assert isinstance(comp, Refusal)
+    assert comp.reason == "admissibility_refused"
+    assert "unit_mismatch" in comp.detail
+
+
+def test_non_digit_quantity_refuses() -> None:
+    comp = comprehend_quantitative("Liam has several stickers. How many stickers does Liam have?")
+    assert isinstance(comp, Refusal)
+    assert comp.reason == "non_digit_quantity"
+
+
+def test_unreadable_clause_refuses() -> None:
+    comp = comprehend_quantitative("The weather is nice today.")
+    assert isinstance(comp, Refusal)