diff --git a/generate/quantitative_comprehension.py b/generate/quantitative_comprehension.py
index d5ef5a21..59268ba8 100644
--- a/generate/quantitative_comprehension.py
+++ b/generate/quantitative_comprehension.py
@@ -66,21 +66,27 @@ def _resolve_unit(noun: str) -> str:
     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."""
+    """Successful arithmetic comprehension.
+
+    The question target is no longer a sidecar field — it lives IN the graph as the
+    sole :class:`BoundUnknown` (PR-1). Consumers read it via :func:`single_unknown`,
+    which refuses (returns ``None``) on a graph that does not carry exactly one
+    target rather than silently picking one.
+    """
 
     binding_graph: SemanticSymbolicBindingGraph
-    query: QuantQuery
+
+
+def single_unknown(graph: SemanticSymbolicBindingGraph) -> BoundUnknown | None:
+    """Return the graph's SOLE question target, or ``None`` if it is not exactly one.
+
+    Zero unknowns (no question) and multiple unknowns (ambiguous target) both REFUSE
+    — the caller must not pick one. ``comprehend_quantitative`` always emits exactly
+    one; this guards every other construction path (wrong=0 at the consumer boundary).
+    """
+    return graph.unknowns[0] if len(graph.unknowns) == 1 else None
 
 
 class _QReject(Exception):
@@ -295,10 +301,7 @@ def comprehend_quantitative(text: str, source_id: str = "input") -> QuantCompreh
     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)),
-    )
+    return QuantComprehension(binding_graph=graph)
 
 
 def to_relational_metric(
@@ -338,4 +341,7 @@ def to_relational_metric(
             return None  # unrecognized equation shape -> refuse
     if not relations:
         return None
-    return relations, {"entity": comp.query.entity, "unit": comp.query.unit}
+    target = single_unknown(graph)
+    if target is None:
+        return None  # no/ambiguous question target -> refuse (never pick one)
+    return relations, {"entity": target.symbol_id, "unit": target.expected_unit}
diff --git a/generate/realize/quantitative.py b/generate/realize/quantitative.py
index 62b66731..742ec96b 100644
--- a/generate/realize/quantitative.py
+++ b/generate/realize/quantitative.py
@@ -22,7 +22,7 @@ import numpy as np
 from formation.hashing import sha256_of
 from generate.binding_graph.model import SemanticSymbolicBindingGraph
 from generate.meaning_graph.reader import Refusal
-from generate.quantitative_comprehension import QuantComprehension
+from generate.quantitative_comprehension import QuantComprehension, single_unknown
 from session.context import SessionContext
 from teaching.epistemic import EpistemicStatus
 
@@ -80,13 +80,18 @@ def realize_quantitative(
     if any(e.admissibility_status != "admitted" for e in bg.equations):
         return NotRealized("unadmitted_equation")
 
+    # The question target is the graph's sole BoundUnknown (PR-1/PR-3); refuse a graph
+    # that does not carry exactly one rather than picking one.
+    target = single_unknown(bg)
+    if target is None:
+        return NotRealized("no_single_question_target")
     # Placement: the asked entity's field point. Symbolic/OOV, so deterministic-
     # GIVEN-session-state, NOT subject-determined; the structural key carries
     # correctness. ``probe_ingest`` of an OOV token mutates the shared vocab via
     # insert_transient (session-scoped, excluded from the snapshot); a non-versor
     # construction raises and is caught → NotRealized.
     try:
-        field_state = ctx.probe_ingest([comprehension.query.entity])
+        field_state = ctx.probe_ingest([target.symbol_id])
     except _GROUNDING_FAILURES:
         return NotRealized("grounding_failed")
     versor = np.asarray(field_state.F, dtype=np.float32)
diff --git a/tests/test_quantitative_comprehension.py b/tests/test_quantitative_comprehension.py
index b5e0ee43..862c9cb4 100644
--- a/tests/test_quantitative_comprehension.py
+++ b/tests/test_quantitative_comprehension.py
@@ -8,11 +8,18 @@ reviewer's "do not stamp admissibility" guard, made executable.
 
 from __future__ import annotations
 
-from generate.binding_graph.model import SemanticSymbolicBindingGraph
+from generate.binding_graph.model import (
+    BoundFact,
+    BoundUnknown,
+    SemanticSymbolicBindingGraph,
+    SourceSpanLink,
+    SymbolBinding,
+)
 from generate.meaning_graph.reader import Refusal
 from generate.quantitative_comprehension import (
     QuantComprehension,
     comprehend_quantitative,
+    single_unknown,
     to_relational_metric,
 )
 
@@ -32,24 +39,21 @@ def test_fact_and_more_than_build_binding_graph() -> None:
     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"
+    assert single_unknown(g).symbol_id == "mia"
 
 
 def test_question_target_is_a_bound_unknown_in_the_graph() -> None:
-    # PR-1: the question target lives INSIDE the graph (a BoundUnknown at the terminal
-    # state), not only as the external QuantQuery.
+    # The question target lives INSIDE the graph (a BoundUnknown at the terminal
+    # state) — read via single_unknown, never a sidecar field (PR-3 removed QuantQuery).
     comp = _comp("Liam has 6 stickers. Mia has 4 more stickers than Liam. How many stickers does Mia have?")
-    unknowns = comp.binding_graph.unknowns
-    assert len(unknowns) == 1
-    u = unknowns[0]
+    u = single_unknown(comp.binding_graph)
+    assert u is not None
     assert u.symbol_id == "mia"
     assert u.state_index == "terminal"
     assert u.question_form == "count"
     assert u.expected_unit == "item"
-    # The graph's canonical serialization now carries the target.
+    # The graph's canonical serialization carries the target.
     assert "state=terminal" in comp.binding_graph.to_canonical_string()
-    # Retained convenience stays consistent with the in-graph unknown.
-    assert comp.query.entity == u.symbol_id
 
 
 def test_sum_query_target_is_total_form_unknown() -> None:
@@ -77,9 +81,14 @@ def test_fewer_than_is_subtract() -> None:
     assert eq.operation_kind == "subtract" and eq.rhs_canonical == "noah - 6"
 
 
+def test_sum_query_target_via_single_unknown() -> None:
+    comp = _comp("Dan has 7 coins. Eva has 9 more coins than Dan. How many coins do Dan and Eva have?")
+    assert single_unknown(comp.binding_graph).symbol_id == "total"
+
+
 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"
+    assert single_unknown(comp.binding_graph).symbol_id == "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"}
@@ -120,3 +129,43 @@ def test_non_digit_quantity_refuses() -> None:
 def test_unreadable_clause_refuses() -> None:
     comp = comprehend_quantitative("The weather is nice today.")
     assert isinstance(comp, Refusal)
+
+
+# --------------------------------------------------------------------------- #
+# PR-3 — malformed graphs REFUSE (never pick one of several targets)
+# --------------------------------------------------------------------------- #
+
+
+def _sp() -> SourceSpanLink:
+    return SourceSpanLink(source_id="t", start=0, end=1, text="x")
+
+
+def _graph_with_n_unknowns(n: int) -> SemanticSymbolicBindingGraph:
+    symbols = tuple(
+        SymbolBinding(symbol_id=s, name=s, semantic_role="count",
+                      source_span=_sp(), introduced_by="t", entity=s, unit="item")
+        for s in ("a", "b")
+    )
+    unknowns = tuple(
+        BoundUnknown(symbol_id=s, question_span=_sp(), state_index="terminal",
+                     question_form="count", expected_unit="item")
+        for s in ("a", "b")[:n]
+    )
+    return SemanticSymbolicBindingGraph(
+        symbols=symbols,
+        facts=(BoundFact(symbol_id="a", value="1", source_span=_sp(), unit="item"),),
+        equations=(),
+        unknowns=unknowns,
+    )
+
+
+def test_single_unknown_refuses_zero_and_multiple() -> None:
+    assert single_unknown(_graph_with_n_unknowns(0)) is None  # no question target
+    assert single_unknown(_graph_with_n_unknowns(2)) is None  # ambiguous → refuse, not pick
+    assert single_unknown(_graph_with_n_unknowns(1)) is not None
+
+
+def test_to_relational_metric_refuses_malformed_target() -> None:
+    for n in (0, 2):
+        comp = QuantComprehension(binding_graph=_graph_with_n_unknowns(n))
+        assert to_relational_metric(comp) is None  # refuse rather than emit a guessed query