diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/results/TextExpansionResults.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/results/TextExpansionResults.java
index de679c8e6062e..45aa4d51e0ad6 100644
--- a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/results/TextExpansionResults.java
+++ b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/results/TextExpansionResults.java
@@ -89,8 +89,8 @@ public Object predictedValue() {
     @Override
     void doXContentBody(XContentBuilder builder, Params params) throws IOException {
         builder.startObject(resultsField);
-        for (var vectorDimension : weightedTokens) {
-            vectorDimension.toXContent(builder, params);
+        for (var weightedToken : weightedTokens) {
+            weightedToken.toXContent(builder, params);
         }
         builder.endObject();
     }
diff --git a/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/queries/SparseVectorQueryBuilder.java b/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/queries/SparseVectorQueryBuilder.java
index 52e51d6f65d6b..bcd47cb9acc4e 100644
--- a/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/queries/SparseVectorQueryBuilder.java
+++ b/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/queries/SparseVectorQueryBuilder.java
@@ -67,7 +67,7 @@ public SparseVectorQueryBuilder(
 
     public SparseVectorQueryBuilder(
         String fieldName,
-        String modelText,
+        @Nullable String modelText,
         @Nullable String modelId,
         @Nullable List<WeightedToken> weightedTokens,
         @Nullable TokenPruningConfig tokenPruningConfig
@@ -97,7 +97,7 @@ public SparseVectorQueryBuilder(
     public SparseVectorQueryBuilder(StreamInput in) throws IOException {
         super(in);
         this.fieldName = in.readString();
-        this.modelText = in.readString();
+        this.modelText = in.readOptionalString();
         this.modelId = in.readOptionalString();
         this.tokenPruningConfig = in.readOptionalWriteable(TokenPruningConfig::new);
         this.weightedTokens = in.readOptionalCollectionAsList(WeightedToken::new);
@@ -134,7 +134,7 @@ protected void doWriteTo(StreamOutput out) throws IOException {
             throw new IllegalStateException("supplier must be null, can't serialize suppliers, missing a rewriteAndFetch?");
         }
         out.writeString(fieldName);
-        out.writeString(modelText);
+        out.writeOptionalString(modelText);
         out.writeOptionalString(modelId);
         out.writeOptionalWriteable(tokenPruningConfig);
         out.writeOptionalCollection(weightedTokens, StreamOutput::writeWriteable);
diff --git a/x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/queries/SparseVectorQueryBuilderTests.java b/x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/queries/SparseVectorQueryBuilderTests.java
index ef2dc379b6d4a..976f151ed4eee 100644
--- a/x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/queries/SparseVectorQueryBuilderTests.java
+++ b/x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/queries/SparseVectorQueryBuilderTests.java
@@ -61,8 +61,8 @@ protected SparseVectorQueryBuilder doCreateTestQueryBuilder() {
         TokenPruningConfig tokenPruningConfig = randomBoolean()
             ? new TokenPruningConfig(randomIntBetween(1, 100), randomFloat(), randomBoolean())
             : null;
-        String modelText = randomAlphaOfLength(4);
         String modelId = randomBoolean() ? randomAlphaOfLength(4) : null;
+        String modelText = modelId != null ? randomAlphaOfLength(4) : null;
         List<TextExpansionResults.WeightedToken> weightedTokens = modelId == null ? VECTOR_DIMENSIONS : null;
 
         var builder = new SparseVectorQueryBuilder(RANK_FEATURES_FIELD, modelText, modelId, weightedTokens, tokenPruningConfig);