diff --git a/crates/aura-cli/src/main.rs b/crates/aura-cli/src/main.rs
index 37a4a7e..0787605 100644
--- a/crates/aura-cli/src/main.rs
+++ b/crates/aura-cli/src/main.rs
@@ -1140,7 +1140,15 @@ fn stage1_r_sweep_family(_trace: Option<&str>, data: &DataSource) -> SweepFamily
             let eq_rows: Vec<(Timestamp, Vec<Scalar>)> = rx_eq.try_iter().collect();
             let ex_rows: Vec<(Timestamp, Vec<Scalar>)> = rx_ex.try_iter().collect();
             let r_rows: Vec<(Timestamp, Vec<Scalar>)> = rx_r.try_iter().collect();
-            let named = zip_params(&space, point);
+            // record the swept knobs PLUS the fixed R-defining params (the stop and
+            // bias scale), matching the single run: a family member must be
+            // reproducible from its own manifest (C18), and the constant stop — which
+            // defines 1R — must be visible so cross-member SQN comparability (C10) is
+            // auditable from the family record, not just the floated fast/slow knobs.
+            let mut named = zip_params(&space, point);
+            named.push(("bias_scale".to_string(), Scalar::f64(0.5)));
+            named.push(("stop_length".to_string(), Scalar::i64(STAGE1_R_STOP_LENGTH)));
+            named.push(("stop_k".to_string(), Scalar::f64(STAGE1_R_STOP_K)));
             let mut manifest = sim_optimal_manifest(named, window, 0, pip);
             manifest.broker = stage1_r_broker_label(pip);
             let mut metrics = summarize(&f64_field(&eq_rows, 0), &f64_field(&ex_rows, 0));
diff --git a/crates/aura-cli/tests/cli_run.rs b/crates/aura-cli/tests/cli_run.rs
index 78a6a8e..0088f57 100644
--- a/crates/aura-cli/tests/cli_run.rs
+++ b/crates/aura-cli/tests/cli_run.rs
@@ -1643,6 +1643,13 @@ fn sweep_strategy_stage1_r_ranks_a_family_by_sqn() {
     for line in &lines {
         assert!(line.contains("\"r\":{"), "member must carry an r block: {line}");
         assert!(line.contains("\"sqn\""), "member r block must carry sqn: {line}");
+        // each member records the fixed R-defining params (the stop that defines 1R),
+        // so it is reproducible from its own manifest (C18) and the constant-stop
+        // basis of cross-member SQN comparability (C10) is auditable from the record.
+        assert!(
+            line.contains("\"stop_length\"") && line.contains("\"stop_k\""),
+            "member manifest must record the fixed R-defining stop params: {line}"
+        );
     }
     // rank the family by sqn — highest first.
     let rank = Command::new(BIN)