diff --git a/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/services/elasticsearch/ElasticsearchInternalService.java b/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/services/elasticsearch/ElasticsearchInternalService.java
index 2244622445ecc..ee8d4b0fbbc6b 100644
--- a/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/services/elasticsearch/ElasticsearchInternalService.java
+++ b/x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/services/elasticsearch/ElasticsearchInternalService.java
@@ -59,6 +59,7 @@
 import org.elasticsearch.xpack.inference.chunking.ChunkingSettingsBuilder;
 import org.elasticsearch.xpack.inference.chunking.EmbeddingRequestChunker;
 import org.elasticsearch.xpack.inference.services.ConfigurationParseContext;
+import org.elasticsearch.xpack.inference.services.ServiceUtils;
 import org.elasticsearch.xpack.inference.services.validation.ModelValidatorBuilder;
 
 import java.util.ArrayList;
@@ -504,30 +505,34 @@ public void checkModelConfig(Model model, ActionListener<Model> listener) {
 
     @Override
     public Model updateModelWithEmbeddingDetails(Model model, int embeddingSize) {
-        if (model instanceof CustomElandEmbeddingModel embeddingsModel) {
-            var serviceSettings = embeddingsModel.getServiceSettings();
-
-            var updatedServiceSettings = new CustomElandInternalTextEmbeddingServiceSettings(
-                serviceSettings.getNumAllocations(),
-                serviceSettings.getNumThreads(),
-                serviceSettings.modelId(),
-                serviceSettings.getAdaptiveAllocationsSettings(),
-                embeddingSize,
-                serviceSettings.similarity(),
-                serviceSettings.elementType()
-            );
+        if (model instanceof ElasticsearchInternalModel) {
+            if (model instanceof CustomElandEmbeddingModel embeddingsModel) {
+                var serviceSettings = embeddingsModel.getServiceSettings();
+
+                var updatedServiceSettings = new CustomElandInternalTextEmbeddingServiceSettings(
+                    serviceSettings.getNumAllocations(),
+                    serviceSettings.getNumThreads(),
+                    serviceSettings.modelId(),
+                    serviceSettings.getAdaptiveAllocationsSettings(),
+                    embeddingSize,
+                    serviceSettings.similarity(),
+                    serviceSettings.elementType()
+                );
 
-            return new CustomElandEmbeddingModel(
-                model.getInferenceEntityId(),
-                model.getTaskType(),
-                model.getConfigurations().getService(),
-                updatedServiceSettings,
-                model.getConfigurations().getChunkingSettings()
-            );
+                return new CustomElandEmbeddingModel(
+                    model.getInferenceEntityId(),
+                    model.getTaskType(),
+                    model.getConfigurations().getService(),
+                    updatedServiceSettings,
+                    model.getConfigurations().getChunkingSettings()
+                );
+            } else {
+                // TODO: This is for the E5 case which is text embedding but we didn't previously update the dimensions. Figure out if we do
+                // need to update the dimensions?
+                return model;
+            }
         } else {
-            // TODO: This is for the E5 case which is text embedding but we didn't previously update the dimensions. Figure out if we do
-            // need to update the dimensions?
-            return model;
+            throw ServiceUtils.invalidModelTypeForUpdateModelWithEmbeddingDetails(model.getClass());
         }
     }
 
diff --git a/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/services/elasticsearch/ElasticsearchInternalServiceTests.java b/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/services/elasticsearch/ElasticsearchInternalServiceTests.java
index cad33b56ce235..510a093e9c162 100644
--- a/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/services/elasticsearch/ElasticsearchInternalServiceTests.java
+++ b/x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/services/elasticsearch/ElasticsearchInternalServiceTests.java
@@ -67,11 +67,13 @@
 import org.elasticsearch.xpack.inference.chunking.ChunkingSettingsTests;
 import org.elasticsearch.xpack.inference.chunking.EmbeddingRequestChunker;
 import org.elasticsearch.xpack.inference.services.ServiceFields;
+import org.elasticsearch.xpack.inference.services.openai.completion.OpenAiChatCompletionModelTests;
 import org.junit.After;
 import org.junit.Before;
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mockito;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.EnumSet;
 import java.util.HashMap;
@@ -1509,6 +1511,84 @@ public void testParseRequestConfigEland_SetsDimensionsToOne() {
         assertThat(model, is(expectedModel));
     }
 
+    public void testUpdateModelWithEmbeddingDetails_InvalidModelProvided() throws IOException {
+        var client = mock(Client.class);
+        try (var service = createService(client)) {
+            var model = OpenAiChatCompletionModelTests.createChatCompletionModel(
+                randomAlphaOfLength(10),
+                randomAlphaOfLength(10),
+                randomAlphaOfLength(10),
+                randomAlphaOfLength(10),
+                randomAlphaOfLength(10)
+            );
+            assertThrows(
+                ElasticsearchStatusException.class,
+                () -> { service.updateModelWithEmbeddingDetails(model, randomNonNegativeInt()); }
+            );
+        }
+    }
+
+    public void testUpdateModelWithEmbeddingDetails_NonElandModelProvided() throws IOException {
+        var client = mock(Client.class);
+        try (var service = createService(client)) {
+            var originalModel = new MultilingualE5SmallModel(
+                randomAlphaOfLength(10),
+                TaskType.TEXT_EMBEDDING,
+                randomAlphaOfLength(10),
+                new MultilingualE5SmallInternalServiceSettings(
+                    randomNonNegativeInt(),
+                    randomNonNegativeInt(),
+                    randomAlphaOfLength(10),
+                    null
+                ),
+                null
+            );
+
+            var updatedModel = service.updateModelWithEmbeddingDetails(originalModel, randomNonNegativeInt());
+            assertEquals(originalModel, updatedModel);
+        }
+    }
+
+    public void testUpdateModelWithEmbeddingDetails_ElandModelProvided() throws IOException {
+        var client = mock(Client.class);
+        try (var service = createService(client)) {
+            var originalServiceSettings = new CustomElandInternalTextEmbeddingServiceSettings(
+                randomNonNegativeInt(),
+                randomNonNegativeInt(),
+                randomAlphaOfLength(10),
+                null
+            );
+            var originalModel = new CustomElandEmbeddingModel(
+                randomAlphaOfLength(10),
+                TaskType.TEXT_EMBEDDING,
+                randomAlphaOfLength(10),
+                originalServiceSettings,
+                ChunkingSettingsTests.createRandomChunkingSettings()
+            );
+
+            var embeddingSize = randomNonNegativeInt();
+            var expectedUpdatedServiceSettings = new CustomElandInternalTextEmbeddingServiceSettings(
+                originalServiceSettings.getNumAllocations(),
+                originalServiceSettings.getNumThreads(),
+                originalServiceSettings.modelId(),
+                originalServiceSettings.getAdaptiveAllocationsSettings(),
+                embeddingSize,
+                originalServiceSettings.similarity(),
+                originalServiceSettings.elementType()
+            );
+            var expectedUpdatedModel = new CustomElandEmbeddingModel(
+                originalModel.getInferenceEntityId(),
+                originalModel.getTaskType(),
+                originalModel.getConfigurations().getService(),
+                expectedUpdatedServiceSettings,
+                originalModel.getConfigurations().getChunkingSettings()
+            );
+
+            var actualUpdatedModel = service.updateModelWithEmbeddingDetails(originalModel, embeddingSize);
+            assertEquals(expectedUpdatedModel, actualUpdatedModel);
+        }
+    }
+
     public void testModelVariantDoesNotMatchArchitecturesAndIsNotPlatformAgnostic() {
         {
             assertFalse(