diff --git a/group-coordinator/group-coordinator-api/src/main/java/org/apache/kafka/coordinator/group/api/streams/assignor/AssignmentConfigs.java b/group-coordinator/group-coordinator-api/src/main/java/org/apache/kafka/coordinator/group/api/streams/assignor/AssignmentConfigs.java
new file mode 100644
index 0000000000000..3b416ff93c91f
--- /dev/null
+++ b/group-coordinator/group-coordinator-api/src/main/java/org/apache/kafka/coordinator/group/api/streams/assignor/AssignmentConfigs.java
@@ -0,0 +1,43 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.coordinator.group.api.streams.assignor;
+
+import org.apache.kafka.common.annotation.InterfaceAudience;
+import org.apache.kafka.common.annotation.InterfaceStability;
+
+import java.util.List;
+
+/**
+ * The assignment configurations that the group coordinator passes to the task assignor.
+ *
+ * <p>This interface is not intended to be implemented by task assignors: new configurations may be added to it.
+ */
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public interface AssignmentConfigs {
+
+    /**
+     * @return The number of standby replicas for each task.
+     */
+    int numStandbyReplicas();
+
+    /**
+     * @return The client tags used to distribute standby tasks across racks. The list is unmodifiable.
+     */
+    List<String> rackAwareAssignmentTags();
+
+}
diff --git a/group-coordinator/group-coordinator-api/src/main/java/org/apache/kafka/coordinator/group/api/streams/assignor/GroupSpec.java b/group-coordinator/group-coordinator-api/src/main/java/org/apache/kafka/coordinator/group/api/streams/assignor/GroupSpec.java
index 35aeb291bdf3c..03485c14bfb31 100644
--- a/group-coordinator/group-coordinator-api/src/main/java/org/apache/kafka/coordinator/group/api/streams/assignor/GroupSpec.java
+++ b/group-coordinator/group-coordinator-api/src/main/java/org/apache/kafka/coordinator/group/api/streams/assignor/GroupSpec.java
@@ -20,7 +20,6 @@
 import org.apache.kafka.common.annotation.InterfaceStability;
 
 import java.util.Collection;
-import java.util.Map;
 
 /**
  * The group metadata specifications required to compute the target assignment.
@@ -51,8 +50,8 @@ public interface GroupSpec {
     MemberAssignmentState memberAssignmentState(String memberId);
 
     /**
-     * @return Any configurations passed to the assignor. The map is unmodifiable.
+     * @return The assignment configurations passed to the assignor.
      */
-    Map<String, String> configs();
+    AssignmentConfigs configs();
 
 }
diff --git a/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/TargetAssignmentBuilder.java b/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/TargetAssignmentBuilder.java
index 124c392ba42de..32036f04502fe 100644
--- a/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/TargetAssignmentBuilder.java
+++ b/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/TargetAssignmentBuilder.java
@@ -19,10 +19,12 @@
 import org.apache.kafka.common.utils.Time;
 import org.apache.kafka.coordinator.common.runtime.CoordinatorMetadataImage;
 import org.apache.kafka.coordinator.common.runtime.CoordinatorRecord;
+import org.apache.kafka.coordinator.group.api.streams.assignor.AssignmentConfigs;
 import org.apache.kafka.coordinator.group.api.streams.assignor.GroupAssignment;
 import org.apache.kafka.coordinator.group.api.streams.assignor.MemberAssignment;
 import org.apache.kafka.coordinator.group.api.streams.assignor.TaskAssignor;
 import org.apache.kafka.coordinator.group.api.streams.assignor.TaskAssignorException;
+import org.apache.kafka.coordinator.group.streams.assignor.AssignmentConfigsImpl;
 import org.apache.kafka.coordinator.group.streams.assignor.GroupSpecImpl;
 import org.apache.kafka.coordinator.group.streams.assignor.MemberMetadataAndStateImpl;
 import org.apache.kafka.coordinator.group.streams.topics.ConfiguredTopology;
@@ -70,7 +72,7 @@ public class TargetAssignmentBuilder {
     /**
      * The assignment configs.
      */
-    private final Map<String, String> assignmentConfigs;
+    private final AssignmentConfigs assignmentConfigs;
 
     /**
      * The members in the group.
@@ -114,7 +116,7 @@ public TargetAssignmentBuilder(
         this.groupId = Objects.requireNonNull(groupId);
         this.groupEpoch = groupEpoch;
         this.assignor = Objects.requireNonNull(assignor);
-        this.assignmentConfigs = Objects.requireNonNull(assignmentConfigs);
+        this.assignmentConfigs = AssignmentConfigsImpl.fromMap(Objects.requireNonNull(assignmentConfigs));
     }
 
     static MemberMetadataAndStateImpl createMemberMetadataAndState(
diff --git a/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/AssignmentConfigsImpl.java b/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/AssignmentConfigsImpl.java
new file mode 100644
index 0000000000000..437244ddbdc98
--- /dev/null
+++ b/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/AssignmentConfigsImpl.java
@@ -0,0 +1,67 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.coordinator.group.streams.assignor;
+
+import org.apache.kafka.coordinator.group.api.streams.assignor.AssignmentConfigs;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * The assignment configurations for a streams group.
+ *
+ * @param numStandbyReplicas      The number of standby replicas for each task.
+ * @param rackAwareAssignmentTags The client tags used to distribute standby tasks across racks.
+ */
+public record AssignmentConfigsImpl(
+    int numStandbyReplicas,
+    List<String> rackAwareAssignmentTags
+) implements AssignmentConfigs {
+
+    private static final String NUM_STANDBY_REPLICAS_CONFIG = "num.standby.replicas";
+    private static final String RACK_AWARE_ASSIGNMENT_TAGS_CONFIG = "rack.aware.assignment.tags";
+
+    /**
+     * The configs used for a group that has none of them set.
+     */
+    public static final AssignmentConfigsImpl DEFAULT = new AssignmentConfigsImpl(0, List.of());
+
+    public AssignmentConfigsImpl {
+        // The list is exposed to a custom assignor through the public AssignmentConfigs interface.
+        rackAwareAssignmentTags = List.copyOf(Objects.requireNonNull(rackAwareAssignmentTags));
+    }
+
+    /**
+     * Converts the raw assignment configs computed for the group into the typed configs passed to the assignor.
+     */
+    public static AssignmentConfigsImpl fromMap(Map<String, String> configs) {
+        // The map is empty when it was replayed from a group metadata record written before the last assignment
+        // configs were persisted.
+        if (configs.isEmpty()) {
+            return DEFAULT;
+        }
+        // The rack-aware assignment tags are only set when any are configured.
+        String rackAwareAssignmentTags = configs.get(RACK_AWARE_ASSIGNMENT_TAGS_CONFIG);
+        return new AssignmentConfigsImpl(
+            Integer.parseInt(configs.get(NUM_STANDBY_REPLICAS_CONFIG)),
+            rackAwareAssignmentTags == null
+                ? List.of()
+                : List.of(rackAwareAssignmentTags.trim().split("\\s*,\\s*", -1))
+        );
+    }
+}
diff --git a/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/GroupSpecImpl.java b/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/GroupSpecImpl.java
index 19b4d08556bfd..ec408f65a9f48 100644
--- a/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/GroupSpecImpl.java
+++ b/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/GroupSpecImpl.java
@@ -16,6 +16,7 @@
  */
 package org.apache.kafka.coordinator.group.streams.assignor;
 
+import org.apache.kafka.coordinator.group.api.streams.assignor.AssignmentConfigs;
 import org.apache.kafka.coordinator.group.api.streams.assignor.GroupSpec;
 import org.apache.kafka.coordinator.group.api.streams.assignor.MemberAssignmentMetadata;
 import org.apache.kafka.coordinator.group.api.streams.assignor.MemberAssignmentState;
@@ -30,17 +31,17 @@
  *
  * @param members The member metadata keyed by member Id. Each value provides both the
  *                {@link MemberAssignmentMetadata} and the {@link MemberAssignmentState} for the member.
- * @param configs Any configurations passed to the assignor.
+ * @param configs The assignment configurations passed to the assignor.
  */
 public record GroupSpecImpl(
     Map<String, MemberMetadataAndStateImpl> members,
-    Map<String, String> configs
+    AssignmentConfigs configs
 ) implements GroupSpec {
 
     public GroupSpecImpl {
-        // Both maps are exposed to a custom assignor through the public GroupSpec interface.
+        // The map is exposed to a custom assignor through the public GroupSpec interface.
         members = Collections.unmodifiableMap(Objects.requireNonNull(members));
-        configs = Collections.unmodifiableMap(Objects.requireNonNull(configs));
+        Objects.requireNonNull(configs);
     }
 
     @Override
diff --git a/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/StickyTaskAssignor.java b/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/StickyTaskAssignor.java
index 529b07fd4fd74..1d735764b0d67 100644
--- a/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/StickyTaskAssignor.java
+++ b/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/streams/assignor/StickyTaskAssignor.java
@@ -95,9 +95,7 @@ private static LinkedList<TaskId> taskIds(final TopologyDescriber topologyDescri
 
     private static LocalState initialize(final GroupSpec groupSpec, final TopologyDescriber topologyDescriber) {
         final LocalState localState = new LocalState();
-        localState.numStandbyReplicas =
-            groupSpec.configs().isEmpty() ? 0
-                : Integer.parseInt(groupSpec.configs().get("num.standby.replicas"));
+        localState.numStandbyReplicas = groupSpec.configs().numStandbyReplicas();
 
         // Helpers for computing active tasks per member, and tasks per member
         localState.totalActiveTasks = 0;
diff --git a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/GroupMetadataManagerTest.java b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/GroupMetadataManagerTest.java
index c1bbff9439841..c0b58a3924e59 100644
--- a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/GroupMetadataManagerTest.java
+++ b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/GroupMetadataManagerTest.java
@@ -154,6 +154,7 @@
 import org.apache.kafka.coordinator.group.streams.TaskAssignmentTestUtil.TaskRole;
 import org.apache.kafka.coordinator.group.streams.TasksTuple;
 import org.apache.kafka.coordinator.group.streams.TasksTupleWithEpochs;
+import org.apache.kafka.coordinator.group.streams.assignor.AssignmentConfigsImpl;
 import org.apache.kafka.image.MetadataDelta;
 import org.apache.kafka.image.MetadataImage;
 import org.apache.kafka.image.MetadataProvenance;
@@ -23654,7 +23655,7 @@ public void testStreamsGroupDynamicConfigs() {
                     .setWarmupTasks(List.of()));
         assertEquals(2, result.response().data().memberEpoch());
         assertEquals(
-            getDefaultAssignmentConfigs(),
+            new AssignmentConfigsImpl(GroupCoordinatorConfig.STREAMS_GROUP_NUM_STANDBY_REPLICAS_DEFAULT, List.of()),
             assignor.lastPassedAssignmentConfigs()
         );
 
@@ -23693,7 +23694,7 @@ public void testStreamsGroupDynamicConfigs() {
 
         // Verify that the new number of standby replicas is used
         assertEquals(
-            Map.of("num.standby.replicas", "2"),
+            new AssignmentConfigsImpl(2, List.of()),
             assignor.lastPassedAssignmentConfigs()
         );
 
@@ -24041,7 +24042,7 @@ public void testStreamsGroupEvaluatedConfigs() {
         context.assertSessionTimeout(groupId, memberId,
             GroupCoordinatorConfig.STREAMS_GROUP_SESSION_TIMEOUT_MS_DEFAULT);
         assertEquals(
-            getDefaultAssignmentConfigs(),
+            new AssignmentConfigsImpl(GroupCoordinatorConfig.STREAMS_GROUP_NUM_STANDBY_REPLICAS_DEFAULT, List.of()),
             assignor.lastPassedAssignmentConfigs());
         assertEquals(GroupCoordinatorConfig.STREAMS_GROUP_TASK_OFFSET_INTERVAL_MS_DEFAULT,
             result.response().data().taskOffsetIntervalMs());
@@ -24081,7 +24082,7 @@ public void testStreamsGroupEvaluatedConfigs() {
         // Verify that the number of standby replicas is evaluated to max,
         // and task offset interval is evaluated to min
         assertEquals(
-            Map.of("num.standby.replicas", String.valueOf(GroupCoordinatorConfig.STREAMS_GROUP_MAX_STANDBY_REPLICAS_DEFAULT)),
+            new AssignmentConfigsImpl(GroupCoordinatorConfig.STREAMS_GROUP_MAX_STANDBY_REPLICAS_DEFAULT, List.of()),
             assignor.lastPassedAssignmentConfigs());
         assertEquals(GroupCoordinatorConfig.STREAMS_GROUP_MIN_TASK_OFFSET_INTERVAL_MS_DEFAULT,
             result.response().data().taskOffsetIntervalMs());
diff --git a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/MockTaskAssignor.java b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/MockTaskAssignor.java
index 93bab5825e128..d1fc1de6188af 100644
--- a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/MockTaskAssignor.java
+++ b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/MockTaskAssignor.java
@@ -16,6 +16,7 @@
  */
 package org.apache.kafka.coordinator.group.streams;
 
+import org.apache.kafka.coordinator.group.api.streams.assignor.AssignmentConfigs;
 import org.apache.kafka.coordinator.group.api.streams.assignor.GroupAssignment;
 import org.apache.kafka.coordinator.group.api.streams.assignor.GroupSpec;
 import org.apache.kafka.coordinator.group.api.streams.assignor.MemberAssignment;
@@ -31,7 +32,7 @@ public class MockTaskAssignor implements TaskAssignor {
 
     private final String name;
     private GroupAssignment preparedGroupAssignment = null;
-    private Map<String, String> assignmentConfigs = Map.of();
+    private AssignmentConfigs assignmentConfigs = null;
 
     public MockTaskAssignor(String name) {
         this.name = name;
@@ -53,7 +54,7 @@ public void prepareGroupAssignment(Map<String, TasksTuple> memberAssignments) {
                     })));
     }
 
-    public Map<String, String> lastPassedAssignmentConfigs() {
+    public AssignmentConfigs lastPassedAssignmentConfigs() {
         return assignmentConfigs;
     }
 
diff --git a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/TargetAssignmentBuilderTest.java b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/TargetAssignmentBuilderTest.java
index e9f17f11a9324..a09001b24f491 100644
--- a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/TargetAssignmentBuilderTest.java
+++ b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/TargetAssignmentBuilderTest.java
@@ -27,6 +27,7 @@
 import org.apache.kafka.coordinator.group.api.streams.assignor.TaskAssignor;
 import org.apache.kafka.coordinator.group.generated.StreamsGroupMemberMetadataValue;
 import org.apache.kafka.coordinator.group.streams.TaskAssignmentTestUtil.TaskRole;
+import org.apache.kafka.coordinator.group.streams.assignor.AssignmentConfigsImpl;
 import org.apache.kafka.coordinator.group.streams.assignor.GroupSpecImpl;
 import org.apache.kafka.coordinator.group.streams.assignor.MemberMetadataAndStateImpl;
 import org.apache.kafka.coordinator.group.streams.topics.ConfiguredSubtopology;
@@ -479,7 +480,7 @@ public org.apache.kafka.coordinator.group.streams.TargetAssignmentBuilder.Target
             TopologyMetadata topologyMetadata = new TopologyMetadata(metadataImage, subtopologies);
 
             // Prepare the expected assignment spec.
-            GroupSpecImpl groupSpec = new GroupSpecImpl(memberMetadataMap, new HashMap<>());
+            GroupSpecImpl groupSpec = new GroupSpecImpl(memberMetadataMap, AssignmentConfigsImpl.DEFAULT);
 
             // We use `any` here to always return an assignment but use `verify` later on
             // to ensure that the input was correct.
diff --git a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/AssignmentConfigsImplTest.java b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/AssignmentConfigsImplTest.java
new file mode 100644
index 0000000000000..2e619fa0451a5
--- /dev/null
+++ b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/AssignmentConfigsImplTest.java
@@ -0,0 +1,65 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.coordinator.group.streams.assignor;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public class AssignmentConfigsImplTest {
+
+    @Test
+    void testFromEmptyMap() {
+        // A group metadata record written before the last assignment configs were persisted replays as an empty map.
+        assertEquals(AssignmentConfigsImpl.DEFAULT, AssignmentConfigsImpl.fromMap(Map.of()));
+    }
+
+    @Test
+    void testFromMapWithoutRackAwareAssignmentTags() {
+        // The tags are only put in the map when any are configured.
+        assertEquals(
+            new AssignmentConfigsImpl(2, List.of()),
+            AssignmentConfigsImpl.fromMap(Map.of("num.standby.replicas", "2"))
+        );
+    }
+
+    @Test
+    void testFromMap() {
+        assertEquals(
+            new AssignmentConfigsImpl(1, List.of("tag1", "tag2")),
+            AssignmentConfigsImpl.fromMap(Map.of(
+                "num.standby.replicas", "1",
+                "rack.aware.assignment.tags", " tag1 , tag2 "
+            ))
+        );
+    }
+
+    @Test
+    void testRackAwareAssignmentTagsAreUnmodifiable() {
+        List<String> tags = new ArrayList<>(List.of("tag1"));
+        AssignmentConfigsImpl configs = new AssignmentConfigsImpl(0, tags);
+
+        tags.add("tag2");
+        assertEquals(List.of("tag1"), configs.rackAwareAssignmentTags());
+        assertThrows(UnsupportedOperationException.class, () -> configs.rackAwareAssignmentTags().add("tag2"));
+    }
+}
diff --git a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/GroupSpecImplTest.java b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/GroupSpecImplTest.java
index 976289b5e8e59..6d49a4f844913 100644
--- a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/GroupSpecImplTest.java
+++ b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/GroupSpecImplTest.java
@@ -19,13 +19,14 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
 
 
 public class GroupSpecImplTest {
@@ -53,7 +54,7 @@ void setUp() {
 
         groupSpec = new GroupSpecImpl(
             members,
-            new HashMap<>()
+            new AssignmentConfigsImpl(2, new ArrayList<>(List.of("test-tag")))
         );
     }
 
@@ -80,13 +81,14 @@ void testMemberNotFound() {
 
     @Test
     void testConfigs() {
-        assertTrue(groupSpec.configs().isEmpty());
+        assertEquals(2, groupSpec.configs().numStandbyReplicas());
+        assertEquals(List.of("test-tag"), groupSpec.configs().rackAwareAssignmentTags());
     }
 
     @Test
     void testMembersAndConfigsAreUnmodifiable() {
         assertThrows(UnsupportedOperationException.class, () -> groupSpec.members().put("other-member", member));
-        assertThrows(UnsupportedOperationException.class, () -> groupSpec.configs().put("key", "value"));
+        assertThrows(UnsupportedOperationException.class, () -> groupSpec.configs().rackAwareAssignmentTags().add("other-tag"));
     }
 
 }
diff --git a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/MockAssignorTest.java b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/MockAssignorTest.java
index a4d4d914aab51..0d93d3a5f6209 100644
--- a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/MockAssignorTest.java
+++ b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/MockAssignorTest.java
@@ -23,7 +23,6 @@
 
 import org.junit.jupiter.api.Test;
 
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -54,7 +53,7 @@ public void testZeroMembers() {
         TaskAssignorException ex = assertThrows(TaskAssignorException.class, () -> assignor.assign(
             new GroupSpecImpl(
                 Map.of(),
-                new HashMap<>()
+                AssignmentConfigsImpl.DEFAULT
             ),
             new TopologyDescriberImpl(5, List.of("test-subtopology"))
         ));
@@ -92,7 +91,7 @@ public void testDoubleAssignment() {
         TaskAssignorException ex = assertThrows(TaskAssignorException.class, () -> assignor.assign(
             new GroupSpecImpl(
                 Map.of("member1", memberMetadata1, "member2", memberMetadata2),
-                new HashMap<>()
+                AssignmentConfigsImpl.DEFAULT
             ),
             new TopologyDescriberImpl(5, List.of("test-subtopology"))
         ));
@@ -106,7 +105,7 @@ public void testBasicScenario() {
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(
                 Map.of(),
-                new HashMap<>()
+                AssignmentConfigsImpl.DEFAULT
             ),
             new TopologyDescriberImpl(5, List.of())
         );
@@ -133,7 +132,7 @@ public void testSingleMember() {
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(
                 Map.of("test_member", memberMetadata),
-                new HashMap<>()
+                AssignmentConfigsImpl.DEFAULT
             ),
             new TopologyDescriberImpl(4, List.of("test-subtopology"))
         );
@@ -177,7 +176,7 @@ public void testTwoMembersTwoSubtopologies() {
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(
                 mkMap(mkEntry("test_member1", memberMetadata1), mkEntry("test_member2", memberMetadata2)),
-                new HashMap<>()
+                AssignmentConfigsImpl.DEFAULT
             ),
             new TopologyDescriberImpl(4, List.of("test-subtopology1", "test-subtopology2"))
         );
@@ -235,7 +234,7 @@ public void testTwoMembersTwoSubtopologiesStickiness() {
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(
                 mkMap(mkEntry("test_member1", memberMetadata1), mkEntry("test_member2", memberMetadata2)),
-                new HashMap<>()
+                AssignmentConfigsImpl.DEFAULT
             ),
             new TopologyDescriberImpl(4, List.of("test-subtopology1", "test-subtopology2"))
         );
diff --git a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/StickyTaskAssignorTest.java b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/StickyTaskAssignorTest.java
index f623f196f2337..412a64daadc61 100644
--- a/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/StickyTaskAssignorTest.java
+++ b/group-coordinator/src/test/java/org/apache/kafka/coordinator/group/streams/assignor/StickyTaskAssignorTest.java
@@ -46,7 +46,6 @@
 
 public class StickyTaskAssignorTest {
 
-    public static final String NUM_STANDBY_REPLICAS_CONFIG = "num.standby.replicas";
     private final StickyTaskAssignor assignor = new StickyTaskAssignor();
 
     @Test
@@ -64,7 +63,7 @@ public void shouldAssignOneActiveTaskToEachProcessWhenTaskCountSameAsProcessCoun
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(
                 mkMap(mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3)),
-                new HashMap<>()
+                AssignmentConfigsImpl.DEFAULT
             ),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
@@ -93,7 +92,7 @@ public void shouldAssignTopicGroupIdEvenlyAcrossClientsWithNoStandByTasks() {
             mkEntry("member3_1", memberMetadata31), mkEntry("member3_2", memberMetadata32));
 
         final GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, Arrays.asList("test-subtopology1", "test-subtopology2"))
         );
 
@@ -122,7 +121,7 @@ public void shouldAssignTopicGroupIdEvenlyAcrossClientsWithStandByTasks() {
 
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(members,
-                mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, "1"))),
+                new AssignmentConfigsImpl(1, List.of())),
             new TopologyDescriberImpl(3, true, Arrays.asList("test-subtopology1", "test-subtopology2"))
         );
 
@@ -144,7 +143,7 @@ public void shouldNotMigrateActiveTaskToOtherProcess() {
         Map<String, MemberMetadataAndStateImpl> members = mkMap(mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -163,7 +162,7 @@ public void shouldNotMigrateActiveTaskToOtherProcess() {
         members = mkMap(mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3));
 
         result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -186,7 +185,7 @@ public void shouldMigrateActiveTasksToNewProcessWithoutChangingAllAssignments()
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -214,7 +213,7 @@ public void shouldAssignBasedOnCapacity() {
             mkEntry("member1", memberMetadata1), mkEntry("member2_1", memberMetadata21), mkEntry("member2_2", memberMetadata22));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -240,7 +239,7 @@ public void shouldAssignTasksEvenlyWithUnequalTopicGroupSizes() {
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl2()
         );
 
@@ -271,7 +270,7 @@ public void shouldKeepActiveTaskStickinessWhenMoreClientThanActiveTasks() {
             mkEntry("member3", memberMetadata3), mkEntry("member4", memberMetadata4), mkEntry("member5", memberMetadata5));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -305,7 +304,7 @@ public void shouldKeepActiveTaskStickinessWhenMoreClientThanActiveTasks() {
             mkEntry("member3", memberMetadata3), mkEntry("member4", memberMetadata4), mkEntry("member5", memberMetadata5));
 
         result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -338,7 +337,7 @@ public void shouldAssignTasksToClientWithPreviousStandbyTasks() {
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -364,7 +363,7 @@ public void shouldNotAssignStandbyTasksToClientWithPreviousStandbyTasksAndCurren
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, "1"))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(1, List.of())),
             new TopologyDescriberImpl(2, true, List.of("test-subtopology"))
         );
 
@@ -397,7 +396,7 @@ public void shouldAssignBasedOnCapacityWhenMultipleClientHaveStandbyTasks() {
             mkEntry("member2_1", memberMetadata21), mkEntry("member2_2", memberMetadata22));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -428,7 +427,7 @@ public void shouldAssignStandbyTasksToDifferentClientThanCorrespondingActiveTask
 
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(members,
-                mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, "1"))),
+                new AssignmentConfigsImpl(1, List.of())),
             new TopologyDescriberImpl(4, true, List.of("test-subtopology"))
         );
 
@@ -464,7 +463,7 @@ public void shouldAssignMultipleReplicasOfStandbyTask() {
 
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(members,
-                mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, "2"))),
+                new AssignmentConfigsImpl(2, List.of())),
             new TopologyDescriberImpl(3, true, List.of("test-subtopology"))
         );
 
@@ -481,7 +480,7 @@ public void shouldNotAssignStandbyTaskReplicasWhenNoClientAvailableWithoutHaving
 
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(members,
-                mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, "1"))),
+                new AssignmentConfigsImpl(1, List.of())),
             new TopologyDescriberImpl(1, true, List.of("test-subtopology"))
         );
 
@@ -499,7 +498,7 @@ public void shouldAssignActiveAndStandbyTasks() {
 
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(members,
-                mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, "1"))),
+                new AssignmentConfigsImpl(1, List.of())),
             new TopologyDescriberImpl(3, true, List.of("test-subtopology"))
         );
 
@@ -519,7 +518,7 @@ public void shouldAssignAtLeastOneTaskToEachClientIfPossible() {
             mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -541,7 +540,7 @@ public void shouldAssignEachActiveTaskToOneClientWhenMoreClientsThanTasks() {
             mkEntry("member4", memberMetadata4), mkEntry("member5", memberMetadata5), mkEntry("member6", memberMetadata6));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -563,7 +562,7 @@ public void shouldBalanceActiveAndStandbyTasksAcrossAvailableClients() {
 
         final GroupAssignment result = assignor.assign(
             new GroupSpecImpl(members,
-                mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, "1"))),
+                new AssignmentConfigsImpl(1, List.of())),
             new TopologyDescriberImpl(3, true, List.of("test-subtopology"))
         );
 
@@ -581,7 +580,7 @@ public void shouldAssignMoreTasksToClientWithMoreCapacity() {
             mkEntry("member1", memberMetadata1), mkEntry("member2_1", memberMetadata21), mkEntry("member2_2", memberMetadata22));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, Arrays.asList("test-subtopology0", "test-subtopology1", "test-subtopology2", "test-subtopology3"))
         );
 
@@ -599,7 +598,7 @@ public void shouldReBalanceTasksAcrossAllClientsWhenCapacityAndTaskCountTheSame(
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3), mkEntry("member4", memberMetadata4));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(4, false, List.of("test-subtopology"))
         );
 
@@ -618,7 +617,7 @@ public void shouldReBalanceTasksAcrossClientsWhenCapacityLessThanTaskCount() {
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(4, false, List.of("test-subtopology"))
         );
 
@@ -636,7 +635,7 @@ public void shouldRebalanceTasksToClientsBasedOnCapacity() {
             mkEntry("member2", memberMetadata2), mkEntry("member3_1", memberMetadata31), mkEntry("member3_2", memberMetadata32));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(3, false, List.of("test-subtopology"))
         );
 
@@ -655,7 +654,7 @@ public void shouldMoveMinimalNumberOfTasksWhenPreviouslyAboveCapacityAndNewClien
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(4, false, List.of("test-subtopology"))
         );
 
@@ -676,7 +675,7 @@ public void shouldNotMoveAnyTasksWhenNewTasksAdded() {
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(6, false, List.of("test-subtopology"))
         );
 
@@ -697,7 +696,7 @@ public void shouldAssignNewTasksToNewClientWhenPreviousTasksAssignedToOldClients
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(6, false, List.of("test-subtopology"))
         );
 
@@ -730,7 +729,7 @@ public void shouldAssignTasksNotPreviouslyActiveToNewClient() {
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3), mkEntry("newMember", newMemberSpec));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(4, false, Arrays.asList("test-subtopology0", "test-subtopology1", "test-subtopology2"))
         );
 
@@ -762,7 +761,7 @@ public void shouldAssignTasksNotPreviouslyActiveToMultipleNewClients() {
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("bounce_member1", bounce1), mkEntry("bounce_member2", bounce2));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(4, false, Arrays.asList("test-subtopology0", "test-subtopology1", "test-subtopology2"))
         );
 
@@ -784,7 +783,7 @@ public void shouldAssignTasksToNewClient() {
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(2, false, List.of("test-subtopology"))
         );
 
@@ -800,7 +799,7 @@ public void shouldAssignTasksToNewClientWithoutFlippingAssignmentBetweenExisting
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("newMember", newMemberSpec));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(6, false, List.of("test-subtopology"))
         );
 
@@ -826,7 +825,7 @@ public void shouldAssignTasksToNewClientWithoutFlippingAssignmentBetweenExisting
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("newMember", newMemberSpec));
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, new HashMap<>()),
+            new GroupSpecImpl(members, AssignmentConfigsImpl.DEFAULT),
             new TopologyDescriberImpl(7, false, List.of("test-subtopology"))
         );
 
@@ -855,7 +854,7 @@ public void shouldHandleLargeNumberOfTasksWithStandbyAssignment() {
         }
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, String.valueOf(numStandbyReplicas)))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(numStandbyReplicas, List.of())),
             new TopologyDescriberImpl(numTasks, true, List.of("test-subtopology"))
         );
 
@@ -926,7 +925,7 @@ public void shouldHandleOddNumberOfClientsWithStandbyTasks() {
         }
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, String.valueOf(numStandbyReplicas)))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(numStandbyReplicas, List.of())),
             new TopologyDescriberImpl(numTasks, true, List.of("test-subtopology"))
         );
 
@@ -977,7 +976,7 @@ public void shouldHandleHighStandbyReplicaCount() {
         }
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, String.valueOf(numStandbyReplicas)))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(numStandbyReplicas, List.of())),
             new TopologyDescriberImpl(numTasks, true, List.of("test-subtopology"))
         );
 
@@ -1021,7 +1020,7 @@ public void shouldHandleLargeNumberOfSubtopologiesWithStandbyTasks() {
         }
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, String.valueOf(numStandbyReplicas)))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(numStandbyReplicas, List.of())),
             new TopologyDescriberImpl(5, true, subtopologies) // 5 tasks per subtopology
         );
 
@@ -1053,7 +1052,7 @@ public void shouldHandleEdgeCaseWithSingleClientAndMultipleStandbyReplicas() {
         );
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, String.valueOf(numStandbyReplicas)))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(numStandbyReplicas, List.of())),
             new TopologyDescriberImpl(numTasks, true, List.of("test-subtopology"))
         );
 
@@ -1078,7 +1077,7 @@ public void shouldHandleEdgeCaseWithMoreStandbyReplicasThanAvailableClients() {
         }
 
         GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, String.valueOf(numStandbyReplicas)))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(numStandbyReplicas, List.of())),
             new TopologyDescriberImpl(numTasks, true, List.of("test-subtopology"))
         );
 
@@ -1120,7 +1119,7 @@ public void shouldReassignTasksWhenNewNodeJoinsWithExistingActiveAndStandbyAssig
             mkEntry("member1", memberMetadata1), mkEntry("member2", memberMetadata2), mkEntry("member3", memberMetadata3));
 
         final GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, "1"))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(1, List.of())),
             new TopologyDescriberImpl(4, true, List.of("test-subtopology"))
         );
 
@@ -1161,7 +1160,7 @@ public void shouldRangeAssignTasksWhenScalingUp() {
 
         // Two subtopologies with 2 tasks each (4 tasks total) with standby replicas enabled
         final GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, String.valueOf(1)))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(1, List.of())),
             new TopologyDescriberImpl(2, true, Arrays.asList("test-subtopology1", "test-subtopology2"))
         );
 
@@ -1207,7 +1206,7 @@ public void shouldRangeAssignTasksWhenStartingEmpty() {
 
         // Two subtopologies with 2 tasks each (4 tasks total) with standby replicas enabled
         final GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, String.valueOf(1)))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(1, List.of())),
             new TopologyDescriberImpl(2, true, Arrays.asList("test-subtopology1", "test-subtopology2"))
         );
 
@@ -1277,7 +1276,7 @@ public void shouldAssignStandbyTaskToPreviousOwnerBasedOnBelowQuotaCondition() {
         // We have 2 active tasks + 1 standby replica = 4 total tasks
         // Quota per process = 4 tasks / 3 processes = 1.33 -> 2 tasks per process
         final GroupAssignment result = assignor.assign(
-            new GroupSpecImpl(members, mkMap(mkEntry(NUM_STANDBY_REPLICAS_CONFIG, "1"))),
+            new GroupSpecImpl(members, new AssignmentConfigsImpl(1, List.of())),
             new TopologyDescriberImpl(2, true, List.of("test-subtopology"))
         );
 
diff --git a/jmh-benchmarks/src/main/java/org/apache/kafka/jmh/assignor/StreamsAssignorBenchmarkUtils.java b/jmh-benchmarks/src/main/java/org/apache/kafka/jmh/assignor/StreamsAssignorBenchmarkUtils.java
index b1478498a3f42..caa2a619e54ef 100644
--- a/jmh-benchmarks/src/main/java/org/apache/kafka/jmh/assignor/StreamsAssignorBenchmarkUtils.java
+++ b/jmh-benchmarks/src/main/java/org/apache/kafka/jmh/assignor/StreamsAssignorBenchmarkUtils.java
@@ -16,6 +16,7 @@
  */
 package org.apache.kafka.jmh.assignor;
 
+import org.apache.kafka.coordinator.group.api.streams.assignor.AssignmentConfigs;
 import org.apache.kafka.coordinator.group.api.streams.assignor.GroupSpec;
 import org.apache.kafka.coordinator.group.streams.StreamsGroupMember;
 import org.apache.kafka.coordinator.group.streams.assignor.GroupSpecImpl;
@@ -44,7 +45,7 @@ public class StreamsAssignorBenchmarkUtils {
      */
     public static GroupSpec createGroupSpec(
         Map<String, StreamsGroupMember> members,
-        Map<String, String> assignmentConfigs
+        AssignmentConfigs assignmentConfigs
     ) {
         Map<String, MemberMetadataAndStateImpl> memberSpecs = new HashMap<>();
 
diff --git a/jmh-benchmarks/src/main/java/org/apache/kafka/jmh/assignor/StreamsStickyAssignorBenchmark.java b/jmh-benchmarks/src/main/java/org/apache/kafka/jmh/assignor/StreamsStickyAssignorBenchmark.java
index b25c441cf821e..d5f85172c4e56 100644
--- a/jmh-benchmarks/src/main/java/org/apache/kafka/jmh/assignor/StreamsStickyAssignorBenchmark.java
+++ b/jmh-benchmarks/src/main/java/org/apache/kafka/jmh/assignor/StreamsStickyAssignorBenchmark.java
@@ -17,6 +17,7 @@
 package org.apache.kafka.jmh.assignor;
 
 import org.apache.kafka.coordinator.common.runtime.CoordinatorMetadataImage;
+import org.apache.kafka.coordinator.group.api.streams.assignor.AssignmentConfigs;
 import org.apache.kafka.coordinator.group.api.streams.assignor.GroupAssignment;
 import org.apache.kafka.coordinator.group.api.streams.assignor.GroupSpec;
 import org.apache.kafka.coordinator.group.api.streams.assignor.MemberAssignment;
@@ -24,6 +25,7 @@
 import org.apache.kafka.coordinator.group.api.streams.assignor.TopologyDescriber;
 import org.apache.kafka.coordinator.group.streams.StreamsGroupMember;
 import org.apache.kafka.coordinator.group.streams.TopologyMetadata;
+import org.apache.kafka.coordinator.group.streams.assignor.AssignmentConfigsImpl;
 import org.apache.kafka.coordinator.group.streams.assignor.GroupSpecImpl;
 import org.apache.kafka.coordinator.group.streams.assignor.MemberMetadataAndStateImpl;
 import org.apache.kafka.coordinator.group.streams.assignor.StickyTaskAssignor;
@@ -91,7 +93,7 @@ public enum AssignmentType {
 
     private TopologyDescriber topologyDescriber;
 
-    private Map<String, String> assignmentConfigs;
+    private AssignmentConfigs assignmentConfigs;
 
     @Setup(Level.Trial)
     public void setup() {
@@ -106,10 +108,7 @@ public void setup() {
         taskAssignor = new StickyTaskAssignor();
 
         Map<String, StreamsGroupMember> members = createMembers();
-        this.assignmentConfigs = Map.of(
-            "num.standby.replicas",
-            Integer.toString(standbyReplicas)
-        );
+        this.assignmentConfigs = new AssignmentConfigsImpl(standbyReplicas, List.of());
         this.groupSpec = StreamsAssignorBenchmarkUtils.createGroupSpec(members, assignmentConfigs);
 
         if (assignmentType == AssignmentType.INCREMENTAL) {