diff --git a/evals/constraint_oracle/verified_producer.py b/evals/constraint_oracle/verified_producer.py
new file mode 100644
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+++ b/evals/constraint_oracle/verified_producer.py
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+"""P1-B — the gold-setup-backed OFF-SERVING R2 verification producer.
+
+The first consumer of the P1-A VERIFIED contract (``core.epistemic_disclosure.verified_contract``).
+Given an R2 problem (prose ``text``) and the INDEPENDENTLY hand-authored gold SETUP
+(``ConstraintProblem``), it constructs a :class:`VerificationProof` and runs it through
+the contract. It answers exactly one question:
+
+    Can CORE construct a VerificationProof that survives the P1-A contract, off-serving?
+
+**WHAT THIS IS — and is NOT.**
+
+  * It IS a validation of the VERIFIED contract + producer mechanics off-serving, using
+    reader-vs-gold-setup convergence as the two independent reads.
+  * It is NOT a serving-time VERIFIED producer. It depends on the eval-lane gold setup,
+    which does not exist at serving time. It CANNOT move any serving metric and CANNOT
+    emit a served ``[verified]``.
+  * Serving-time independence (a non-gold, structurally-distinct second reader) is a
+    SEPARATE, larger rung — explicitly deferred, not solved here.
+
+**The two independent reads** (the contract's independence + convergence, honestly):
+
+  * primary read   = ``read_constraint_problem(text)`` (lineage ``constraint_reader_v1``)
+  * independent read = the gold-authored setup            (lineage ``constraint_gold_author_v1``)
+  * convergence    = the two ``constraint_setup_signature`` digests are equal.
+
+The gold *answer* never enters the proof — only the gold *structure* (a reading), through
+the SAME canonical signature used for the primary read. A wrong reader structure diverges
+from the gold-authored structure → ``reads_disagree`` → NOT_VERIFIED (the poison case).
+
+Off-serving: imports no ``generate.derivation`` / ``core.reliability_gate``.
+"""
+
+from __future__ import annotations
+
+import hashlib
+from dataclasses import dataclass
+
+from core.comprehension_attempt.model import ComprehensionAttempt
+from core.epistemic_disclosure.disclosure_claim import DisclosureClaim
+from core.epistemic_disclosure.limitation import (
+    LimitationAssessment,
+    assess_from_attempt,
+)
+from core.epistemic_disclosure.verified_contract import (
+    VerificationProof,
+    VerificationResult,
+    VerificationVerdict,
+    disclosure_for_verification,
+    evaluate_verification,
+)
+from core.epistemic_state import EpistemicState
+from evals.constraint_oracle.signature import (
+    constraint_setup_signature,
+    constraints_signature,
+)
+from generate.constraint_comprehension.model import ConstraintProblem
+from generate.constraint_comprehension.reader import read_constraint_problem
+from generate.constraint_comprehension.solver import solve_constraint_problem
+from generate.meaning_graph.reader import Refusal
+
+#: The two reader lineages — DISTINCT so the contract's independence check passes. Named
+#: explicitly so nobody later mistakes ``constraint_gold_author_v1`` for a serving reader.
+CONSTRAINT_READER_LINEAGE = "constraint_reader_v1"
+CONSTRAINT_GOLD_AUTHOR_LINEAGE = "constraint_gold_author_v1"
+
+#: The producer's own refusal reason (the reader refused → no primary read exists).
+REASON_READER_REFUSED = "reader_refused"
+
+
+def _sha(payload: str) -> str:
+    """Deterministic hex digest of a canonical string payload."""
+    return hashlib.sha256(payload.encode("utf-8")).hexdigest()
+
+
+def _back_substitutes(problem: ConstraintProblem, solution: dict[str, int]) -> bool:
+    """True iff ``solution`` satisfies EVERY constraint exactly (integer; never rounds).
+
+    Back-substitution into the STATED constraints — proves the solver was faithful to the
+    structure it was handed. It CANNOT catch a wrong read (that is the independent read's
+    job); it catches a wrong solve.
+    """
+    for constraint in problem.constraints:
+        lhs = constraint.lhs.constant + sum(
+            coeff * solution.get(symbol, 0) for symbol, coeff in constraint.lhs.terms
+        )
+        if lhs != constraint.rhs:
+            return False
+    return True
+
+
+@dataclass(frozen=True, slots=True)
+class R2VerificationOutcome:
+    """The producer's structured outcome: the contract verdict, the proof (``None`` only
+    when the reader refused and no primary read exists), the limitation (on refusal), and
+    the routed state/claim — reached ONLY via :func:`disclosure_for_verification`."""
+
+    result: VerificationResult
+    proof: VerificationProof | None
+    limitation: LimitationAssessment | None
+    epistemic_state: EpistemicState
+    disclosure_claim: DisclosureClaim
+
+
+def verify_r2(text: str, gold_setup: ConstraintProblem) -> R2VerificationOutcome:
+    """Build and evaluate a VerificationProof for one R2 problem, off-serving.
+
+    ``gold_setup`` is the INDEPENDENT read — the hand-authored canonical setup (setup
+    fields only; the gold ANSWER is never an input here). The reader provides the primary
+    read. The result is routed to a state/claim ONLY through the sanctioned contract gate.
+    """
+    primary = read_constraint_problem(text)
+
+    # Reader refused → there is no primary read; classify the refusal as a limitation and
+    # do NOT verify. No proof object exists to evaluate.
+    if isinstance(primary, Refusal):
+        limitation = assess_from_attempt(
+            ComprehensionAttempt(
+                organ="r2_constraints",
+                outcome="setup_refused",
+                refusal_reason=primary.reason,
+            )
+        )
+        result = VerificationResult(
+            verdict=VerificationVerdict.NOT_VERIFIED,
+            failed_checks=(REASON_READER_REFUSED,),
+        )
+        state, claim = disclosure_for_verification(result)
+        return R2VerificationOutcome(
+            result=result,
+            proof=None,
+            limitation=limitation,
+            epistemic_state=state,
+            disclosure_claim=claim,
+        )
+
+    # The reader produced a setup. Solve it (the derivation from the STATED quantities) and
+    # back-substitute. The gold answer is NEVER consulted — only the reader's own solve.
+    solution = solve_constraint_problem(primary)
+    if isinstance(solution, Refusal):
+        boundary_clear = False
+        derivation_digest = ""
+        back_substitution_digest = ""
+    else:
+        boundary_clear = True
+        bound = tuple(sorted(solution.items()))
+        derivation_digest = _sha(
+            repr(("derivation", constraints_signature(primary.constraints), bound))
+        )
+        back_substitution_digest = (
+            _sha(repr(("back_substitution", bound)))
+            if _back_substitutes(primary, solution)
+            else ""
+        )
+
+    proof = VerificationProof(
+        source_problem_digest=_sha(text),
+        primary_reader_lineage=CONSTRAINT_READER_LINEAGE,
+        independent_reader_lineage=CONSTRAINT_GOLD_AUTHOR_LINEAGE,
+        primary_read_digest=_sha(repr(constraint_setup_signature(primary))),
+        independent_read_digest=_sha(repr(constraint_setup_signature(gold_setup))),
+        derivation_digest=derivation_digest,
+        back_substitution_digest=back_substitution_digest,
+        boundary_clear=boundary_clear,
+        # Setup-only verification has no answer-key path, so no contradiction can arise
+        # here; the contract still enforces it (P1-A test_contradiction_blocks_verification).
+        contradiction_clear=True,
+    )
+    result = evaluate_verification(proof, limitation=None)
+    state, claim = disclosure_for_verification(result)
+    return R2VerificationOutcome(
+        result=result,
+        proof=proof,
+        limitation=None,
+        epistemic_state=state,
+        disclosure_claim=claim,
+    )
+
+
+__all__ = [
+    "CONSTRAINT_GOLD_AUTHOR_LINEAGE",
+    "CONSTRAINT_READER_LINEAGE",
+    "REASON_READER_REFUSED",
+    "R2VerificationOutcome",
+    "verify_r2",
+]
diff --git a/tests/test_verified_r2_producer.py b/tests/test_verified_r2_producer.py
new file mode 100644
index 00000000..8fc39cfa
--- /dev/null
+++ b/tests/test_verified_r2_producer.py
@@ -0,0 +1,202 @@
+"""P1-B — tests for the gold-setup-backed OFF-SERVING R2 verification producer.
+
+The producer is NOT a serving-time VERIFIED producer: it uses the eval-lane gold SETUP
+(never the gold answer) as the independent read. These tests prove it constructs real
+VerificationProof objects that survive the P1-A contract on real R2 problems, AND that a
+wrong/divergent read never verifies (wrong=0 for the producer).
+"""
+
+from __future__ import annotations
+
+import ast
+import inspect
+import pathlib
+
+from core.epistemic_disclosure.disclosure_claim import DisclosureClaim
+from core.epistemic_disclosure.verified_contract import (
+    REASON_BOUNDARY_FIRED,
+    REASON_READS_DISAGREE,
+    VerificationVerdict,
+    disclosure_for_verification,
+)
+from core.epistemic_state import EpistemicState
+from evals.constraint_oracle.runner import _load_r2_gold, gold_to_problem
+from evals.constraint_oracle.signature import constraint_setup_signature
+from evals.constraint_oracle.verified_producer import (
+    CONSTRAINT_GOLD_AUTHOR_LINEAGE,
+    CONSTRAINT_READER_LINEAGE,
+    verify_r2,
+)
+from generate.constraint_comprehension.model import ConstraintProblem
+from generate.constraint_comprehension.reader import read_constraint_problem
+from generate.meaning_graph.reader import Refusal
+
+
+def _gold():
+    return _load_r2_gold()
+
+
+def _solved_record():
+    return next(r for r in _gold() if r.get("expect") == "solved")
+
+
+# --- the producer verifies real problems, and NEVER on a divergent read ------------- #
+
+def test_integration_real_gold_verifies_some_and_never_on_divergence():
+    records = _gold()
+    assert records
+    # 'reader_refuses' fixtures carry no setup fields (there is no canonical setup for a
+    # problem the reader must refuse). The reader refuses first, so gold_setup is unused on
+    # that path — a placeholder keeps the loop uniform.
+    placeholder = gold_to_problem(_solved_record())
+    verified = 0
+    for rec in records:
+        has_setup = "unknowns" in rec
+        gold = gold_to_problem(rec) if has_setup else placeholder
+        outcome = verify_r2(rec["text"], gold)
+        primary = read_constraint_problem(rec["text"])
+
+        if isinstance(primary, Refusal):
+            assert outcome.proof is None, rec["id"]
+            assert outcome.limitation is not None, rec["id"]
+            assert outcome.result.verdict is VerificationVerdict.NOT_VERIFIED, rec["id"]
+            continue
+
+        if not has_setup:
+            # reader unexpectedly read a reader_refuses case; it must still not verify
+            assert outcome.result.verdict is VerificationVerdict.NOT_VERIFIED, rec["id"]
+            continue
+
+        reads_converge = (
+            constraint_setup_signature(primary) == constraint_setup_signature(gold)
+        )
+        if outcome.result.verdict is VerificationVerdict.VERIFIED:
+            verified += 1
+            # wrong=0 for the producer: a VERIFIED proof must have converged reads, a real
+            # back-substitution, and the routed verified state/claim.
+            assert reads_converge, rec["id"]
+            assert outcome.proof is not None and outcome.proof.back_substitution_digest != ""
+            assert (outcome.epistemic_state, outcome.disclosure_claim) == (
+                EpistemicState.VERIFIED,
+                DisclosureClaim.VERIFIED,
+            )
+        elif not reads_converge:
+            assert REASON_READS_DISAGREE in outcome.result.failed_checks, rec["id"]
+
+    assert verified >= 1, "producer should verify at least one real R2 problem"
+
+
+def test_all_solved_records_verify():
+    """Every gold 'solved' record (reader reads it, solver solves it) produces a VERIFIED
+    proof — the producer's positive headline on real problems."""
+    solved = [r for r in _gold() if r.get("expect") == "solved"]
+    assert solved
+    for rec in solved:
+        outcome = verify_r2(rec["text"], gold_to_problem(rec))
+        assert outcome.result.verdict is VerificationVerdict.VERIFIED, rec["id"]
+        assert outcome.disclosure_claim is DisclosureClaim.VERIFIED, rec["id"]
+
+
+# --- the poison: a wrong / divergent independent read ------------------------------- #
+
+def test_divergent_independent_read_is_reads_disagree():
+    records = _gold()
+    readable = next(
+        r for r in records if not isinstance(read_constraint_problem(r["text"]), Refusal)
+    )
+    primary_sig = constraint_setup_signature(read_constraint_problem(readable["text"]))
+    divergent_setup = next(
+        gold_to_problem(r)
+        for r in records
+        if constraint_setup_signature(gold_to_problem(r)) != primary_sig
+    )
+    outcome = verify_r2(readable["text"], divergent_setup)
+    assert outcome.result.verdict is VerificationVerdict.NOT_VERIFIED
+    assert REASON_READS_DISAGREE in outcome.result.failed_checks
+    assert outcome.disclosure_claim is not DisclosureClaim.VERIFIED
+
+
+# --- reader refusal / solver boundary ----------------------------------------------- #
+
+def test_reader_refusal_yields_no_proof_and_a_limitation():
+    outcome = verify_r2("", gold_to_problem(_gold()[0]))  # empty text → reader refuses
+    assert outcome.proof is None
+    assert outcome.result.verdict is VerificationVerdict.NOT_VERIFIED
+    assert outcome.limitation is not None
+    assert outcome.epistemic_state is not EpistemicState.VERIFIED
+
+
+def test_solver_boundary_records_do_not_verify():
+    refusers = [r for r in _gold() if r.get("expect") == "solver_refuses"]
+    assert refusers
+    for rec in refusers:
+        outcome = verify_r2(rec["text"], gold_to_problem(rec))
+        assert outcome.result.verdict is VerificationVerdict.NOT_VERIFIED, rec["id"]
+        if outcome.proof is not None:
+            # reader matched gold but solver refused → boundary fired
+            assert (
+                REASON_BOUNDARY_FIRED in outcome.result.failed_checks
+                or REASON_READS_DISAGREE in outcome.result.failed_checks
+            ), rec["id"]
+
+
+# --- the contract's independence + the sanctioned route ----------------------------- #
+
+def test_lineages_are_distinct_and_named():
+    assert CONSTRAINT_READER_LINEAGE != CONSTRAINT_GOLD_AUTHOR_LINEAGE
+    assert CONSTRAINT_GOLD_AUTHOR_LINEAGE == "constraint_gold_author_v1"
+
+
+def test_produced_proof_uses_distinct_lineages():
+    rec = _solved_record()
+    outcome = verify_r2(rec["text"], gold_to_problem(rec))
+    assert outcome.proof is not None
+    assert outcome.proof.primary_reader_lineage != outcome.proof.independent_reader_lineage
+
+
+def test_verified_state_and_claim_route_only_through_the_contract_gate():
+    rec = _solved_record()
+    outcome = verify_r2(rec["text"], gold_to_problem(rec))
+    assert outcome.result.verdict is VerificationVerdict.VERIFIED
+    assert (outcome.epistemic_state, outcome.disclosure_claim) == disclosure_for_verification(
+        outcome.result
+    )
+
+
+def test_all_proof_digests_populated_on_verified():
+    rec = _solved_record()
+    outcome = verify_r2(rec["text"], gold_to_problem(rec))
+    p = outcome.proof
+    assert p is not None
+    for digest in (
+        p.source_problem_digest,
+        p.primary_read_digest,
+        p.independent_read_digest,
+        p.derivation_digest,
+        p.back_substitution_digest,
+    ):
+        assert digest, "every replay-critical digest must be populated on a VERIFIED proof"
+
+
+# --- the gold ANSWER can never enter the proof -------------------------------------- #
+
+def test_gold_answer_cannot_enter_the_proof():
+    """Structural: the producer takes only (text, ConstraintProblem), and ConstraintProblem
+    carries no answer field — so the gold answer cannot be an input to verification."""
+    params = list(inspect.signature(verify_r2).parameters)
+    assert params == ["text", "gold_setup"]
+    assert "answer" not in ConstraintProblem.__dataclass_fields__
+    assert "gold" not in ConstraintProblem.__dataclass_fields__
+
+
+# --- hygiene ------------------------------------------------------------------------ #
+
+def test_producer_is_off_serving():
+    import evals.constraint_oracle.verified_producer as mod
+
+    module_path = mod.__file__
+    assert module_path is not None
+    src = pathlib.Path(module_path).read_text()
+    mods = [n.module or "" for n in ast.walk(ast.parse(src)) if isinstance(n, ast.ImportFrom)]
+    forbidden = [m for m in mods if "generate.derivation" in m or "reliability_gate" in m]
+    assert forbidden == []