diff --git a/server/tests/derivation_harness.rs b/server/tests/derivation_harness.rs
index 582483b2c..e409687da 100644
--- a/server/tests/derivation_harness.rs
+++ b/server/tests/derivation_harness.rs
@@ -841,7 +841,7 @@ fn law_climate_vegetation_no_skip_temperature_sweep() {
     let mut last: Option<VegetationClass> = None;
     for t_i in (-60i32..=30).rev().step_by(5) {
         let temp = Some(t_i as f32);
-        let vc = derive_vegetation(temp, moisture_q, elev_q, false);
+        let vc = derive_vegetation(temp, moisture_q, elev_q, false, false);
         if let Some(prev) = last {
             if prev == VegetationClass::Forest && vc == VegetationClass::Barren {
                 panic!(
@@ -861,7 +861,7 @@ fn law_climate_vegetation_no_skip_elevation_sweep() {
     let moisture_q = 55;
     let mut last: Option<VegetationClass> = None;
     for elev_q in (0i32..=100).step_by(5) {
-        let vc = derive_vegetation(temp, moisture_q, elev_q, false);
+        let vc = derive_vegetation(temp, moisture_q, elev_q, false, false);
         if let Some(prev) = last {
             if prev == VegetationClass::Forest && vc == VegetationClass::Barren {
                 panic!(
@@ -898,7 +898,7 @@ fn law_climate_vegetation_full_grid_no_skip() {
         for elev_q in (0i32..=100).step_by(10) {
             let mut last: Option<VegetationClass> = None;
             for &temp in &temps_desc {
-                let vc = derive_vegetation(temp, moisture_q, elev_q, false);
+                let vc = derive_vegetation(temp, moisture_q, elev_q, false, false);
                 if let Some(prev) = last {
                     if prev == VegetationClass::Forest && vc == VegetationClass::Barren {
                         panic!(
@@ -919,7 +919,7 @@ fn law_climate_vegetation_riparian_near_perennial_water() {
     // near_perennial_water=true must produce a Riparian variant in viable zones.
 
     // Forest zone → RiparianThicket.
-    let vc_forest = derive_vegetation(Some(18.0), 60, 20, true);
+    let vc_forest = derive_vegetation(Some(18.0), 60, 20, true, false);
     assert!(
         matches!(
             vc_forest,
@@ -930,7 +930,7 @@ fn law_climate_vegetation_riparian_near_perennial_water() {
     );
 
     // Scrub zone → RiparianScrub.
-    let vc_scrub = derive_vegetation(Some(5.0), 30, 50, true);
+    let vc_scrub = derive_vegetation(Some(5.0), 30, 50, true, false);
     assert!(
         matches!(
             vc_scrub,
@@ -941,7 +941,7 @@ fn law_climate_vegetation_riparian_near_perennial_water() {
     );
 
     // Hyper-arid Barren zone + perennial water → RiparianScrub oasis (D-239 §8).
-    let vc_arid = derive_vegetation(Some(20.0), 3, 10, true);
+    let vc_arid = derive_vegetation(Some(20.0), 3, 10, true, false);
     assert_eq!(
         vc_arid,
         VegetationClass::RiparianScrub,
@@ -957,7 +957,7 @@ fn law_climate_vegetation_airless_always_absent() {
     for moisture_q in [0, 30, 70, 100] {
         for elev_q in [0, 50, 100] {
             for near_water in [false, true] {
-                let vc = derive_vegetation(None, moisture_q, elev_q, near_water);
+                let vc = derive_vegetation(None, moisture_q, elev_q, near_water, false);
                 assert_eq!(
                     vc,
                     VegetationClass::Absent,
diff --git a/server/tests/golden/believability.json b/server/tests/golden/believability.json
index da2796ca3..0e2f02e82 100644
--- a/server/tests/golden/believability.json
+++ b/server/tests/golden/believability.json
@@ -6,38 +6,38 @@
     "voxel_sampled_districts": 64,
     "contrast": {
       "moisture_q": {
-        "min": 32,
+        "min": 31,
         "max": 80,
-        "distinct": 49
+        "distinct": 48
       },
       "elev_q": {
         "min": 0,
-        "max": 98,
-        "distinct": 99
+        "max": 100,
+        "distinct": 101
       },
       "slope_q": {
         "min": 0,
-        "max": 13,
-        "distinct": 14
+        "max": 30,
+        "distinct": 30
       },
       "ocean_fraction_q": {
         "min": 0,
         "max": 100,
-        "distinct": 65
+        "distinct": 44
       },
       "morphology_zones": 9,
-      "vegetation_classes": 3,
+      "vegetation_classes": 4,
       "terrain_materials": 4,
-      "voxel_relief_m": 20,
+      "voxel_relief_m": 24,
       "micro_habitat_distinct": 2
     },
     "coherence": {
-      "water_districts": 49,
-      "water_districts_wet": 44,
+      "water_districts": 46,
+      "water_districts_wet": 46,
       "drainage_samples": 0,
       "drainage_monotonic": 0,
       "vegetation_samples": 64,
-      "vegetated_districts": 8
+      "vegetated_districts": 7
     }
   },
   {
@@ -49,32 +49,32 @@
       "moisture_q": {
         "min": 0,
         "max": 20,
-        "distinct": 21
+        "distinct": 20
       },
       "elev_q": {
         "min": 0,
-        "max": 99,
-        "distinct": 100
+        "max": 100,
+        "distinct": 101
       },
       "slope_q": {
         "min": 0,
-        "max": 6,
-        "distinct": 7
+        "max": 15,
+        "distinct": 14
       },
       "ocean_fraction_q": {
         "min": 0,
         "max": 100,
-        "distinct": 65
+        "distinct": 38
       },
-      "morphology_zones": 9,
-      "vegetation_classes": 1,
-      "terrain_materials": 4,
-      "voxel_relief_m": 19,
+      "morphology_zones": 6,
+      "vegetation_classes": 2,
+      "terrain_materials": 2,
+      "voxel_relief_m": 21,
       "micro_habitat_distinct": 0
     },
     "coherence": {
-      "water_districts": 25,
-      "water_districts_wet": 22,
+      "water_districts": 19,
+      "water_districts_wet": 19,
       "drainage_samples": 0,
       "drainage_monotonic": 0,
       "vegetation_samples": 64,