diff --git a/jouleclaw/jouleclaw-rs/crates/jouleclaw-compose/src/verified.rs b/jouleclaw/jouleclaw-rs/crates/jouleclaw-compose/src/verified.rs
index 139bd6a8c..746a20a74 100644
--- a/jouleclaw/jouleclaw-rs/crates/jouleclaw-compose/src/verified.rs
+++ b/jouleclaw/jouleclaw-rs/crates/jouleclaw-compose/src/verified.rs
@@ -36,6 +36,10 @@ use crate::provenance::cache_key_for_subquery;
 /// Either an [`Answer`] (Verified / Degraded / Partial) or a
 /// structured [`Refusal`]. Returned by [`compose_verified_answer`]
 /// so the caller doesn't need to peek at the verdict.
+// One per query, so the size gap between an answer and a refusal costs
+// nothing measurable; boxing the answer would only add an allocation and
+// change a public enum that callers match on.
+#[allow(clippy::large_enum_variant)]
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 pub enum AnswerOrRefusal {
     Answer(Answer),
@@ -319,6 +323,9 @@ fn build_provenance(inputs: &ComposeInputs<'_>) -> Provenance {
         items: inputs.items.to_vec(),
         claims: inputs.claims.to_vec(),
         entailments: inputs.report.entailments_consulted.clone(),
+        // The verifier's declaration travels with its results, so a stored
+        // answer can be re-verified against the same claim.
+        entailment_backing: inputs.report.grounding_backing.clone(),
         cache_key: combined,
         metadata: Default::default(),
     }
@@ -564,6 +571,42 @@ mod tests {
             .contains(&"I13".to_string()), "I13 should be added");
     }
 
+    /// The answer's provenance carries the backing the verifier declared,
+    /// beside the entailment results it covers, so an answer read back from
+    /// a cache can be held to the same claim. Any backing, the floor
+    /// included, travels unchanged.
+    #[test]
+    fn the_answer_carries_the_verifiers_backing() {
+        for backing in [
+            Some(Backing::Unconsulted),
+            Some(Backing::SingleModel { model_id: "nli".into() }),
+            None,
+        ] {
+            let p = plan();
+            let it = item("Paris is the capital of France.");
+            let seg = DraftSegment {
+                segment_id: "s0".into(),
+                text: "Wikidata: Paris is the capital of France.".into(),
+                cited_item_ids: vec![it.item_id],
+            };
+            let claim = claim_for("s0", "Paris is the capital of France.");
+            let mut report = report_proceed(p.plan_id);
+            report.grounding_backing = backing.clone();
+            let inputs = ComposeInputs {
+                plan: &p,
+                draft_segments: &[seg],
+                claims: &[claim],
+                items: &[it],
+                report: &report,
+                joules_spent_total: 1.0,
+                latency_ms: 1,
+            };
+            let result = compose_verified_answer(&inputs).unwrap();
+            let ans = result.as_answer().expect("Answer");
+            assert_eq!(ans.provenance.entailment_backing, backing);
+        }
+    }
+
     #[test]
     fn drop_action_removes_segment_and_records_caveat() {
         let p = plan();
diff --git a/jouleclaw/jouleclaw-rs/crates/jouleclaw-edge-cli/src/pipeline.rs b/jouleclaw/jouleclaw-rs/crates/jouleclaw-edge-cli/src/pipeline.rs
index db6f54081..81ee9afb0 100644
--- a/jouleclaw/jouleclaw-rs/crates/jouleclaw-edge-cli/src/pipeline.rs
+++ b/jouleclaw/jouleclaw-rs/crates/jouleclaw-edge-cli/src/pipeline.rs
@@ -477,24 +477,23 @@ fn rebuild_output_from_cache(
                 entailments_consulted: a.provenance.entailments.clone(),
                 invariants_verified: a.invariants_verified.clone(),
                 joules_spent: 0.0,
-                // The cache preserves the entailment *results* but not the
-                // backing the original producer declared, so this rebuild
-                // cannot re-make that claim — it declares the floor.
+                // The backing the original verifier declared, stored with the
+                // entailment results in the answer's provenance, so the
+                // rebuilt report makes the same claim and
+                // `require_substantive_grounding` checks it against the same
+                // results. An answer cached before the backing was stored has
+                // none, and declares the floor.
                 //
-                // Deriving one from the cached `model_id`s would be the
-                // laundering path: a run backed by `FixtureEntailer` records
-                // model_id "fixture-entailer", and reconstructing
-                // `SingleModel` from it would promote a stand-in into a
-                // substantive backing on the way out of the cache. A backing
-                // is an assertion the producer made; evidence that a model ran
-                // is not the same as a claim about what its labels are worth.
-                //
-                // Consequence, stated rather than hidden: a rehydrated report
-                // is refused by `require_substantive_grounding`. The fix is to
-                // persist the backing alongside the entailments in
-                // `Provenance`, which is a cache-format change and not this
-                // change.
-                grounding_backing: Some(Backing::Unstated),
+                // Never derived from the cached `model_id`s: a run backed by
+                // `FixtureEntailer` records model_id "fixture-entailer", and
+                // reconstructing `SingleModel` from it would promote a
+                // stand-in into a substantive backing on the way out of the
+                // cache. A backing is an assertion the producer made; evidence
+                // that a model ran is not a claim about what its labels are
+                // worth.
+                grounding_backing: Some(
+                    a.provenance.entailment_backing.clone().unwrap_or(Backing::Unstated),
+                ),
                 metadata: Default::default(),
             },
         ),
@@ -819,3 +818,91 @@ fn axes_for_template_claim() -> KnowledgeAxes {
         metadata: Default::default(),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use jouleclaw_schema::{
+        Answer, AnswerStatus, Backing, EntailmentLabel, EntailmentProbabilities, EntailmentResult,
+        GroundingError, Provenance,
+    };
+
+    /// A cached answer whose one entailment came from `model_id`, its
+    /// provenance carrying `backing`.
+    fn cached(model_id: &str, backing: Option<Backing>) -> CachedAnswer {
+        let entailment = EntailmentResult {
+            schema_version: "2.0".into(),
+            result_id: uuid::Uuid::new_v4(),
+            claim_id: uuid::Uuid::new_v4(),
+            premise_item_ids: vec![],
+            label: EntailmentLabel::Entails,
+            label_probabilities: EntailmentProbabilities { entails: 0.9, neutral: 0.08, contradicts: 0.02 },
+            running_e_value: None,
+            model_id: model_id.into(),
+            joules_spent: 0.0,
+            metadata: Default::default(),
+        };
+        let plan_id = uuid::Uuid::new_v4();
+        CachedAnswer {
+            schema_version: "1.0".into(),
+            cache_key: "k".into(),
+            cached_at: Utc::now(),
+            query_text: "q".into(),
+            result: AnswerOrRefusal::Answer(Answer {
+                schema_version: "2.0".into(),
+                answer_id: uuid::Uuid::new_v4(),
+                plan_id,
+                status: AnswerStatus::Verified,
+                segments: vec![],
+                provenance: Provenance {
+                    schema_version: "2.0".into(),
+                    plan_id,
+                    items: vec![],
+                    claims: vec![],
+                    entailments: vec![entailment],
+                    entailment_backing: backing,
+                    cache_key: "k".into(),
+                    metadata: Default::default(),
+                },
+                invariants_verified: vec![],
+                joules_spent_total: 0.0,
+                latency_ms: 0,
+                caveats: vec![],
+                emitted_at: Utc::now(),
+                metadata: Default::default(),
+            }),
+        }
+    }
+
+    /// An answer cached with its backing comes back out of the cache with the
+    /// same backing, held to the same results: a single model's labels are
+    /// grounded again, where every cached answer used to be refused.
+    #[test]
+    fn a_cached_answer_keeps_the_backing_its_verifier_declared() {
+        let backing = Backing::SingleModel { model_id: "nli-model".into() };
+        let out = rebuild_output_from_cache("q", cached("nli-model", Some(backing.clone())), StageTimings::default());
+        assert_eq!(out.report.require_substantive_grounding(), Ok(&backing));
+    }
+
+    /// The stored backing is a claim, still checked against the results it
+    /// came with: a fixture stays a fixture, a backing naming another model
+    /// than the one whose results are cached is refused, and an answer cached
+    /// before backings were stored declares the floor.
+    #[test]
+    fn a_cached_backing_is_never_promoted_or_trusted_past_its_results() {
+        let fixture = Backing::Fixture { model_ids: vec!["fixture-entailer".into()] };
+        let out = rebuild_output_from_cache("q", cached("fixture-entailer", Some(fixture)), StageTimings::default());
+        assert!(matches!(out.report.require_substantive_grounding(), Err(GroundingError::Fixture { .. })));
+
+        let claims_other = Backing::SingleModel { model_id: "a-better-model".into() };
+        let out = rebuild_output_from_cache("q", cached("nli-model", Some(claims_other)), StageTimings::default());
+        assert!(matches!(
+            out.report.require_substantive_grounding(),
+            Err(GroundingError::BackingDisagreesWithEvidence { .. })
+        ));
+
+        let out = rebuild_output_from_cache("q", cached("nli-model", None), StageTimings::default());
+        assert_eq!(out.report.require_substantive_grounding(), Err(GroundingError::Unstated));
+    }
+}
+
diff --git a/jouleclaw/jouleclaw-rs/crates/jouleclaw-schema/src/answer.rs b/jouleclaw/jouleclaw-rs/crates/jouleclaw-schema/src/answer.rs
index 0a1cd17b5..388f53d06 100644
--- a/jouleclaw/jouleclaw-rs/crates/jouleclaw-schema/src/answer.rs
+++ b/jouleclaw/jouleclaw-rs/crates/jouleclaw-schema/src/answer.rs
@@ -12,7 +12,7 @@ use uuid::Uuid;
 
 use crate::atomic_claim::AtomicClaim;
 use crate::common::Metadata;
-use crate::entailment::EntailmentResult;
+use crate::entailment::{Backing, EntailmentResult};
 use crate::epistemic::ClaimAttribution;
 use crate::knowledge_axes::KnowledgeAxes;
 use crate::retrieved_item::RetrievedItem;
@@ -69,6 +69,19 @@ pub struct Provenance {
     pub claims: Vec<AtomicClaim>,
     /// Every entailment result consulted (focused subset).
     pub entailments: Vec<EntailmentResult>,
+    /// What the labels in [`Self::entailments`] rest on: the backing the
+    /// verifier declared for them
+    /// ([`crate::VerificationReport::grounding_backing`]), carried with the
+    /// results so that a report rebuilt from a stored answer states the same
+    /// backing, and is held to it by
+    /// [`crate::VerificationReport::require_substantive_grounding`]. Without
+    /// it, a rebuilt report could only declare the floor, and every cached
+    /// answer was refused as ungrounded.
+    ///
+    /// Omitted from the wire when absent, so answers written before it
+    /// serialize byte-identically; absent reads as unstated.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub entailment_backing: Option<Backing>,
     /// Cache key produced from the sub-queries (§7.3).
     pub cache_key: String,
     #[serde(default)]
@@ -174,6 +187,7 @@ mod tests {
                 items: vec![],
                 claims: vec![],
                 entailments: vec![],
+                entailment_backing: None,
                 cache_key: "ab".into(),
                 metadata: Default::default(),
             },
@@ -185,6 +199,17 @@ mod tests {
             metadata: Default::default(),
         };
         let json = serde_json::to_string(&a).unwrap();
+        // Absent, the backing is not on the wire: answers written before it
+        // existed keep their bytes.
+        assert!(!json.contains("entailment_backing"), "{json}");
+        let back: Answer = serde_json::from_str(&json).unwrap();
+        assert_eq!(a, back);
+
+        // Present, it round-trips.
+        let mut a = a;
+        a.provenance.entailment_backing = Some(Backing::SingleModel { model_id: "nli".into() });
+        let json = serde_json::to_string(&a).unwrap();
+        assert!(json.contains("entailment_backing"), "{json}");
         let back: Answer = serde_json::from_str(&json).unwrap();
         assert_eq!(a, back);
     }