backend/src/main/java/com/recipeapp/planning/PlanningService.java

@@ -135,6 +135,12 @@ public class PlanningService {
                 .map(cl -> cl.getRecipe().getId())
                 .collect(Collectors.toSet());
 
+        List<SimulatedSlot> currentSlots = plan.getSlots().stream()
+                .map(s -> new SimulatedSlot(s.getRecipe(), s.getSlotDate()))
+                .toList();
+        double currentScore = currentSlots.isEmpty() ? 10.0
+                : scoreFromSimulatedSlots(currentSlots, config, recentlyCookedIds);
+
         List<Recipe> allRecipes = recipeRepository.findByHouseholdIdAndDeletedAtIsNull(householdId);
 
         Set<String> lowerTagFilters = tagFilters.stream()
@@ -145,11 +151,13 @@ public class PlanningService {
                 .filter(r -> !usedRecipeIds.contains(r.getId()))
                 .filter(r -> matchesAllTags(r, lowerTagFilters))
                 .map(candidate -> {
-                    double score = simulateVarietyScore(
+                    double simulatedScore = simulateVarietyScore(
                             plan, candidate, slotDate, config, recentlyCookedIds);
-                    return new SuggestionResponse.SuggestionItem(toSlotRecipe(candidate), score);
+                    double scoreDelta = simulatedScore - currentScore;
+                    boolean hasConflict = scoreDelta <= 0;
+                    return new SuggestionResponse.SuggestionItem(toSlotRecipe(candidate), scoreDelta, hasConflict);
                 })
-                .sorted((a, b) -> Double.compare(b.simulatedScore(), a.simulatedScore()))
+                .sorted((a, b) -> Double.compare(b.scoreDelta(), a.scoreDelta()))
                 .limit(limit)
                 .toList();
 

backend/src/main/java/com/recipeapp/planning/dto/SuggestionResponse.java

@@ -6,6 +6,7 @@ public record SuggestionResponse(List<SuggestionItem> suggestions) {
 
     public record SuggestionItem(
             SlotResponse.SlotRecipe recipe,
-            double simulatedScore
+            double scoreDelta,
+            boolean hasConflict
     ) {}
 }

backend/src/test/java/com/recipeapp/planning/SuggestionsTest.java

@@ -165,7 +165,7 @@ class SuggestionsTest {
         }
 
         @Test
-        void emptyPlanWithRecipesShouldReturnAllWithPerfectScore() {
+        void emptyPlanWithRecipesShouldReturnAllWithZeroDelta() {
             var plan = createPlan();
             var r1 = createRecipe("Pasta");
             var r2 = createRecipe("Salad");
@@ -179,8 +179,9 @@ class SuggestionsTest {
                     HOUSEHOLD_ID, plan.getId(), MONDAY, List.of(), 5);
 
             assertThat(result.suggestions()).hasSize(3);
+            // Empty plan → currentScore = 10.0; no conflicts → scoreDelta = 0.0 for all
             assertThat(result.suggestions()).allSatisfy(s ->
-                    assertThat(s.simulatedScore()).isEqualTo(10.0));
+                    assertThat(s.scoreDelta()).isEqualTo(0.0));
         }
 
         @Test
@@ -221,6 +222,117 @@ class SuggestionsTest {
         }
     }
 
+    // ═══════════════════════════════════════════════════════════
+    // Category 1b: scoreDelta and hasConflict
+    // ═══════════════════════════════════════════════════════════
+
+    @Nested
+    class ScoreDeltaAndHasConflict {
+
+        @Test
+        void recipeWithNoConflictsOnEmptyPlanShouldHaveZeroDeltaAndHasConflict() {
+            // Empty plan → currentScore = 10.0. Clean recipe → simulatedScore = 10.0.
+            // scoreDelta = 0.0, hasConflict = (0.0 <= 0) = true
+            var plan = createPlan();
+            var recipe = createRecipe("Clean Recipe");
+            stubPlan(plan);
+            stubDefaultConfig();
+            stubRecipes(recipe);
+            stubNoCookingLogs();
+
+            SuggestionResponse result = planningService.getSuggestions(
+                    HOUSEHOLD_ID, plan.getId(), MONDAY, List.of(), 5);
+
+            assertThat(result.suggestions()).hasSize(1);
+            var item = result.suggestions().getFirst();
+            assertThat(item.scoreDelta()).isEqualTo(0.0);
+            assertThat(item.hasConflict()).isTrue();
+        }
+
+        @Test
+        void recipeWithTagConflictShouldHaveNegativeDeltaAndHasConflict() {
+            // Existing slot Mon=Monday Pasta (cuisine tag). Adding Tue=More Pasta → tag repeat penalty (-1.5).
+            // currentScore = 10.0 (1 slot, no consecutive). simulatedScore = 10.0 - 1.5 = 8.5.
+            // scoreDelta = -1.5, hasConflict = true.
+            var plan = createPlan();
+            var pastaTag = createTag("Pasta", "cuisine");
+            var existingRecipe = createRecipe("Monday Pasta");
+            addTag(existingRecipe, pastaTag);
+            addSlot(plan, existingRecipe, MONDAY);
+
+            var candidate = createRecipe("More Pasta");
+            addTag(candidate, pastaTag);
+
+            stubPlan(plan);
+            stubDefaultConfig();
+            stubRecipes(existingRecipe, candidate);
+            stubNoCookingLogs();
+
+            SuggestionResponse result = planningService.getSuggestions(
+                    HOUSEHOLD_ID, plan.getId(), MONDAY.plusDays(1), List.of(), 5);
+
+            assertThat(result.suggestions()).hasSize(1);
+            var item = result.suggestions().getFirst();
+            assertThat(item.scoreDelta()).isEqualTo(-1.5);
+            assertThat(item.hasConflict()).isTrue();
+        }
+
+        @Test
+        void recipeWithIngredientConflictShouldHaveNegativeDeltaAndHasConflict() {
+            // Existing slot Mon=Tomato Soup (tomato ingredient). Adding Tue=Tomato Pasta → overlap (-0.3).
+            // currentScore = 10.0, simulatedScore = 9.7, scoreDelta = -0.3, hasConflict = true.
+            var plan = createPlan();
+            var tomato = createIngredient("Tomatoes", false);
+            var existingRecipe = createRecipe("Tomato Soup");
+            addIngredient(existingRecipe, tomato);
+            addSlot(plan, existingRecipe, MONDAY);
+
+            var candidate = createRecipe("Tomato Pasta");
+            addIngredient(candidate, tomato);
+
+            stubPlan(plan);
+            stubDefaultConfig();
+            stubRecipes(existingRecipe, candidate);
+            stubNoCookingLogs();
+
+            SuggestionResponse result = planningService.getSuggestions(
+                    HOUSEHOLD_ID, plan.getId(), MONDAY.plusDays(1), List.of(), 5);
+
+            assertThat(result.suggestions()).hasSize(1);
+            var item = result.suggestions().getFirst();
+            assertThat(item.scoreDelta()).isCloseTo(-0.3, within(0.001));
+            assertThat(item.hasConflict()).isTrue();
+        }
+
+        @Test
+        void scoreDeltaIsSortedDescendingCleanBeforeConflicting() {
+            // Clean recipe (scoreDelta = 0.0) should rank above conflicting (scoreDelta < 0).
+            var plan = createPlan();
+            var pastaTag = createTag("Pasta", "cuisine");
+            var existingRecipe = createRecipe("Monday Pasta");
+            addTag(existingRecipe, pastaTag);
+            addSlot(plan, existingRecipe, MONDAY);
+
+            var cleanRecipe = createRecipe("Plain Rice");
+            var conflictingRecipe = createRecipe("More Pasta");
+            addTag(conflictingRecipe, pastaTag);
+
+            stubPlan(plan);
+            stubDefaultConfig();
+            stubRecipes(existingRecipe, cleanRecipe, conflictingRecipe);
+            stubNoCookingLogs();
+
+            SuggestionResponse result = planningService.getSuggestions(
+                    HOUSEHOLD_ID, plan.getId(), MONDAY.plusDays(1), List.of(), 5);
+
+            assertThat(result.suggestions()).hasSize(2);
+            assertThat(result.suggestions().get(0).recipe().name()).isEqualTo("Plain Rice");
+            assertThat(result.suggestions().get(0).scoreDelta()).isEqualTo(0.0);
+            assertThat(result.suggestions().get(1).recipe().name()).isEqualTo("More Pasta");
+            assertThat(result.suggestions().get(1).scoreDelta()).isEqualTo(-1.5);
+        }
+    }
+
     // ═══════════════════════════════════════════════════════════
     // Category 2: Exclusion of In-Plan Recipes
     // ═══════════════════════════════════════════════════════════
@@ -402,8 +514,8 @@ class SuggestionsTest {
             assertThat(result.suggestions()).hasSize(2);
             // B should rank higher (no tag penalty)
             assertThat(result.suggestions().get(0).recipe().name()).isEqualTo("Plain Rice");
-            assertThat(result.suggestions().get(0).simulatedScore())
-                    .isGreaterThan(result.suggestions().get(1).simulatedScore());
+            assertThat(result.suggestions().get(0).scoreDelta())
+                    .isGreaterThan(result.suggestions().get(1).scoreDelta());
         }
 
         @Test
@@ -428,8 +540,8 @@ class SuggestionsTest {
                     HOUSEHOLD_ID, plan.getId(), MONDAY.plusDays(1), List.of(), 5);
 
             assertThat(result.suggestions()).hasSize(2);
-            assertThat(result.suggestions().get(0).simulatedScore())
-                    .isEqualTo(result.suggestions().get(1).simulatedScore());
+            assertThat(result.suggestions().get(0).scoreDelta())
+                    .isEqualTo(result.suggestions().get(1).scoreDelta());
         }
 
         @Test
@@ -453,8 +565,8 @@ class SuggestionsTest {
                     HOUSEHOLD_ID, plan.getId(), MONDAY.plusDays(1), List.of(), 5);
 
             assertThat(result.suggestions()).hasSize(1);
-            // No penalty — dietary not tracked
-            assertThat(result.suggestions().getFirst().simulatedScore()).isEqualTo(10.0);
+            // No penalty — dietary not tracked → scoreDelta = 0.0
+            assertThat(result.suggestions().getFirst().scoreDelta()).isEqualTo(0.0);
         }
     }
 
@@ -492,8 +604,8 @@ class SuggestionsTest {
 
             assertThat(result.suggestions()).hasSize(2);
             assertThat(result.suggestions().get(0).recipe().name()).isEqualTo("Mushroom Risotto");
-            assertThat(result.suggestions().get(0).simulatedScore())
-                    .isGreaterThan(result.suggestions().get(1).simulatedScore());
+            assertThat(result.suggestions().get(0).scoreDelta())
+                    .isGreaterThan(result.suggestions().get(1).scoreDelta());
         }
 
         @Test
@@ -519,7 +631,8 @@ class SuggestionsTest {
                     HOUSEHOLD_ID, plan.getId(), MONDAY.plusDays(1), List.of(), 5);
 
             assertThat(result.suggestions()).hasSize(1);
-            assertThat(result.suggestions().getFirst().simulatedScore()).isEqualTo(10.0);
+            // Staples ignored → scoreDelta = 0.0
+            assertThat(result.suggestions().getFirst().scoreDelta()).isEqualTo(0.0);
         }
     }
 
@@ -547,8 +660,8 @@ class SuggestionsTest {
 
             assertThat(result.suggestions()).hasSize(2);
             assertThat(result.suggestions().get(0).recipe().name()).isEqualTo("Stir Fry");
-            assertThat(result.suggestions().get(0).simulatedScore())
-                    .isGreaterThan(result.suggestions().get(1).simulatedScore());
+            assertThat(result.suggestions().get(0).scoreDelta())
+                    .isGreaterThan(result.suggestions().get(1).scoreDelta());
         }
 
         @Test
@@ -566,7 +679,8 @@ class SuggestionsTest {
                     HOUSEHOLD_ID, plan.getId(), MONDAY, List.of(), 5);
 
             assertThat(result.suggestions()).hasSize(1);
-            assertThat(result.suggestions().getFirst().simulatedScore()).isEqualTo(10.0);
+            // No penalty → scoreDelta = 0.0
+            assertThat(result.suggestions().getFirst().scoreDelta()).isEqualTo(0.0);
         }
     }
 
@@ -631,7 +745,7 @@ class SuggestionsTest {
         }
 
         @Test
-        void rankingOrderShouldBeBySimulatedScoreDescending() {
+        void rankingOrderShouldBeByScoreDeltaDescending() {
             var plan = createPlan();
             var pastaTag = createTag("Pasta", "cuisine");
             var tomato = createIngredient("Tomatoes", false);
@@ -666,11 +780,11 @@ class SuggestionsTest {
             assertThat(result.suggestions().get(1).recipe().name()).isEqualTo("Dry Pasta");
             assertThat(result.suggestions().get(2).recipe().name()).isEqualTo("Tomato Pasta");
 
-            // Verify scores are strictly descending
-            assertThat(result.suggestions().get(0).simulatedScore())
-                    .isGreaterThan(result.suggestions().get(1).simulatedScore());
-            assertThat(result.suggestions().get(1).simulatedScore())
-                    .isGreaterThan(result.suggestions().get(2).simulatedScore());
+            // Verify scoreDelta is strictly descending
+            assertThat(result.suggestions().get(0).scoreDelta())
+                    .isGreaterThan(result.suggestions().get(1).scoreDelta());
+            assertThat(result.suggestions().get(1).scoreDelta())
+                    .isGreaterThan(result.suggestions().get(2).scoreDelta());
         }
 
         @Test
@@ -688,8 +802,8 @@ class SuggestionsTest {
                     HOUSEHOLD_ID, plan.getId(), MONDAY, List.of(), 5);
 
             assertThat(result.suggestions()).hasSize(2);
-            assertThat(result.suggestions().get(0).simulatedScore())
-                    .isEqualTo(result.suggestions().get(1).simulatedScore());
+            assertThat(result.suggestions().get(0).scoreDelta())
+                    .isEqualTo(result.suggestions().get(1).scoreDelta());
         }
     }
 
@@ -726,7 +840,7 @@ class SuggestionsTest {
             addTag(c1, pastaTag);
             addIngredient(c1, tomato);
 
-            // Candidate 2: Chicken only → protein repeat with Mon
+            // Candidate 2: Chicken only → protein repeat with Mon (Mon→Wed not consecutive)
             var c2 = createRecipe("Chicken Salad");
             addTag(c2, chickenTag);
 
@@ -745,7 +859,7 @@ class SuggestionsTest {
             stubPlan(plan);
             stubDefaultConfig();
             stubRecipes(monRecipe, tueRecipe, c1, c2, c3, c4, c5);
-            // c1 was cooked recently
+            // c1 was cooked recently (within 14-day window)
             stubCookingLogs(createCookingLog(c1, MONDAY.minusDays(3)));
 
             // Slot date = Wednesday (adjacent to Tuesday)
@@ -754,19 +868,20 @@ class SuggestionsTest {
 
             assertThat(result.suggestions()).hasSize(5);
 
-            // c2, c4, c5 all score 10.0 (no penalties — Chicken Mon→Wed not consecutive)
+            // currentScore = 10.0 (Mon+Tue plan: no consecutive conflicts between just those 2 slots)
+            // c2, c4, c5: no additional conflicts → scoreDelta = 0.0
             var topThree = result.suggestions().subList(0, 3);
             assertThat(topThree).extracting(s -> s.recipe().name())
                     .containsExactlyInAnyOrder("Chicken Salad", "Mushroom Risotto", "Lentil Soup");
-            assertThat(topThree).allSatisfy(s -> assertThat(s.simulatedScore()).isEqualTo(10.0));
+            assertThat(topThree).allSatisfy(s -> assertThat(s.scoreDelta()).isEqualTo(0.0));
 
-            // c3 (Cheese Omelette) has ingredient overlap Tue→Wed: -0.3
+            // c3 (Cheese Omelette) has ingredient overlap Tue→Wed: scoreDelta = -0.3
             assertThat(result.suggestions().get(3).recipe().name()).isEqualTo("Cheese Omelette");
-            assertThat(result.suggestions().get(3).simulatedScore()).isCloseTo(9.7, within(0.001));
+            assertThat(result.suggestions().get(3).scoreDelta()).isCloseTo(-0.3, within(0.001));
 
-            // c1 (Tomato Spaghetti) has recent repeat: -1.0
+            // c1 (Tomato Spaghetti) has recent repeat: scoreDelta = -1.0
             assertThat(result.suggestions().get(4).recipe().name()).isEqualTo("Tomato Spaghetti");
-            assertThat(result.suggestions().get(4).simulatedScore()).isEqualTo(9.0);
+            assertThat(result.suggestions().get(4).scoreDelta()).isEqualTo(-1.0);
         }
 
         @Test
@@ -800,7 +915,7 @@ class SuggestionsTest {
                     HOUSEHOLD_ID, plan.getId(), MONDAY.plusDays(1),
                     List.of("Quick meal"), 5);
 
-            // Only quick recipes, ranked by variety
+            // Only quick recipes, ranked by scoreDelta desc
             assertThat(result.suggestions()).hasSize(2);
             assertThat(result.suggestions().get(0).recipe().name()).isEqualTo("Quick Salad");
             assertThat(result.suggestions().get(1).recipe().name()).isEqualTo("Quick Pasta");
@@ -815,7 +930,7 @@ class SuggestionsTest {
     class EdgeCases {
 
         @Test
-        void recipeWithNoTagsOrIngredientsShouldGetPerfectScore() {
+        void recipeWithNoTagsOrIngredientsShouldGetZeroDelta() {
             var plan = createPlan();
             var existingRecipe = createRecipe("Existing");
             addSlot(plan, existingRecipe, MONDAY);
@@ -832,7 +947,8 @@ class SuggestionsTest {
                     HOUSEHOLD_ID, plan.getId(), MONDAY.plusDays(1), List.of(), 5);
 
             assertThat(result.suggestions()).hasSize(1);
-            assertThat(result.suggestions().getFirst().simulatedScore()).isEqualTo(10.0);
+            // No conflicts → scoreDelta = 0.0
+            assertThat(result.suggestions().getFirst().scoreDelta()).isEqualTo(0.0);
         }
 
         @Test

backend/src/test/java/com/recipeapp/planning/WeekPlanControllerTest.java

@@ -162,7 +162,7 @@ class WeekPlanControllerTest {
     @Test
     void getSuggestionsShouldReturn200() throws Exception {
         var recipe = new SlotResponse.SlotRecipe(UUID.randomUUID(), "Stir Fry", "easy", (short) 15, null);
-        var item = new SuggestionResponse.SuggestionItem(recipe, 9.5);
+        var item = new SuggestionResponse.SuggestionItem(recipe, 1.5, false);
         var response = new SuggestionResponse(List.of(item));
 
         when(householdResolver.resolve("sarah@example.com")).thenReturn(HOUSEHOLD_ID);
@@ -175,7 +175,8 @@ class WeekPlanControllerTest {
                         .param("slotDate", "2026-04-08"))
                 .andExpect(status().isOk())
                 .andExpect(jsonPath("$.suggestions[0].recipe.name").value("Stir Fry"))
-                .andExpect(jsonPath("$.suggestions[0].simulatedScore").value(9.5));
+                .andExpect(jsonPath("$.suggestions[0].scoreDelta").value(1.5))
+                .andExpect(jsonPath("$.suggestions[0].hasConflict").value(false));
     }
 
     @Test