diff --git a/client-java/controller/src/main/java/org/evomaster/client/java/controller/mongo/MongoHeuristicsCalculator.java b/client-java/controller/src/main/java/org/evomaster/client/java/controller/mongo/MongoHeuristicsCalculator.java
index bfc6c52ff5..205c4c646e 100644
--- a/client-java/controller/src/main/java/org/evomaster/client/java/controller/mongo/MongoHeuristicsCalculator.java
+++ b/client-java/controller/src/main/java/org/evomaster/client/java/controller/mongo/MongoHeuristicsCalculator.java
@@ -532,6 +532,17 @@ private Truthness computeHeuristic(NotInOperation<?> operation, Object document)
         }
     }
 
+    /**
+     * Computes the heuristic score for a {"f",{"$all": [v1, ..., vn] }} query.
+     * The condition holds when the array held by "f" contains every one of the expected values,
+     * so the score is an AND aggregation over the expected values, each of which is scored by an
+     * OR aggregation over the elements of the array. Note the direction: extra elements in the
+     * document are irrelevant, whereas a missing expected value makes the condition false.
+     *
+     * @param operation the {"f",{"$all": [...]}} query encapsulated as an AllOperation
+     * @param document  the BSON document to evaluate the heuristic score against
+     * @return a Truthness object representing the distance of the document from meeting the condition
+     */
     private Truthness computeHeuristic(AllOperation<?> operation, Object document) {
         requireNonNullQueryAndDocument(operation, document);
 
@@ -550,10 +561,10 @@ private Truthness computeHeuristic(AllOperation<?> operation, Object document) {
                 if (actualValuesList.isEmpty()) {
                     return C_FALSE;
                 } else {
-                    Truthness res = buildAndAggregationTruthness(actualValuesList
+                    Truthness res = buildAndAggregationTruthness(expectedValues
                             .stream()
-                            .map(actualValuesListElement ->
-                                    computeHeuristic(actualValuesListElement, expectedValues))
+                            .map(expectedValue ->
+                                    computeHeuristicForContainedValue(expectedValue, actualValuesList))
                             .toArray(Truthness[]::new));
                     return buildSafeScaledTruthness(res);
                 }
@@ -561,6 +572,23 @@ private Truthness computeHeuristic(AllOperation<?> operation, Object document) {
         }
     }
 
+    /**
+     * Computes the heuristic score for the presence of a single expected value inside the array
+     * held by the queried field, ie an OR aggregation over the elements of that array.
+     *
+     * @param expectedValue a value that a {"f",{"$all": [...]}} query requires to be present
+     * @param actualValues  the non-empty array held by the field "f" in the document
+     * @return a Truthness object representing how close the array is to containing the expected value
+     */
+    private Truthness computeHeuristicForContainedValue(Object expectedValue, List<?> actualValues) {
+        Objects.requireNonNull(actualValues);
+
+        return buildOrAggregationTruthness(actualValues.stream()
+                .map(actualValue -> computeHeuristicComparisonNullableValues(expectedValue, actualValue,
+                        SqlExpressionEvaluator.ComparisonOperatorType.EQUALS_TO))
+                .toArray(Truthness[]::new));
+    }
+
     private static Truthness buildSafeScaledTruthness(Truthness truthness) {
         return buildSafeScaledTruthness(truthness.getOfTrue());
     }
diff --git a/client-java/controller/src/test/java/org/evomaster/client/java/controller/mongo/MongoHeuristicsCalculatorTest.java b/client-java/controller/src/test/java/org/evomaster/client/java/controller/mongo/MongoHeuristicsCalculatorTest.java
index 50675c235e..b330d2c219 100644
--- a/client-java/controller/src/test/java/org/evomaster/client/java/controller/mongo/MongoHeuristicsCalculatorTest.java
+++ b/client-java/controller/src/test/java/org/evomaster/client/java/controller/mongo/MongoHeuristicsCalculatorTest.java
@@ -273,6 +273,40 @@ public void testAllBothActualAndExpectedListsAreEmpty() {
         assertTrue(calculator.computeHeuristicDocument(convertToDocument(allQuery), document).isFalse());
     }
 
+    @Test
+    public void testAllMatchesWhenDocumentArrayHasExtraElements() {
+        // $all only requires the expected values to be present; extra elements are irrelevant
+        Document doc = new Document().append("employees", new ArrayList<>(Arrays.asList(1, 5, 6)));
+        Bson allQuery = Filters.all("employees", new ArrayList<>(Arrays.asList(1, 5)));
+        MongoHeuristicsCalculator calculator = new MongoHeuristicsCalculator();
+        assertTrue(calculator.computeHeuristicDocument(convertToDocument(allQuery), doc).isTrue());
+    }
+
+    @Test
+    public void testAllDoesNotMatchWhenAnExpectedValueIsMissing() {
+        // the array contains 1, but not 2 nor 3, so the condition does not hold
+        Document doc = new Document().append("employees", new ArrayList<>(Arrays.asList(1)));
+        Bson allQuery = Filters.all("employees", new ArrayList<>(Arrays.asList(1, 2, 3)));
+        MongoHeuristicsCalculator calculator = new MongoHeuristicsCalculator();
+        assertTrue(calculator.computeHeuristicDocument(convertToDocument(allQuery), doc).isFalse());
+    }
+
+    @Test
+    public void testAllGivesBetterScoreWhenFewerExpectedValuesAreMissing() {
+        Bson allQuery = Filters.all("employees", new ArrayList<>(Arrays.asList(1, 2, 3)));
+        Document closer = new Document().append("employees", new ArrayList<>(Arrays.asList(1, 2)));
+        Document farther = new Document().append("employees", new ArrayList<>(Arrays.asList(1)));
+
+        MongoHeuristicsCalculator calculator = new MongoHeuristicsCalculator();
+        Truthness closerTruthness = calculator.computeHeuristicDocument(convertToDocument(allQuery), closer);
+        Truthness fartherTruthness = calculator.computeHeuristicDocument(convertToDocument(allQuery), farther);
+
+        assertTrue(closerTruthness.isFalse());
+        assertTrue(fartherTruthness.isFalse());
+        assertTrue(closerTruthness.getOfTrue() > fartherTruthness.getOfTrue(),
+                "a document missing fewer expected values must be scored closer to true");
+    }
+
 
     @Test
     public void testSize() {