diff --git a/docs/changelog/128153.yaml b/docs/changelog/128153.yaml
new file mode 100644
index 0000000000000..fda435438ff53
--- /dev/null
+++ b/docs/changelog/128153.yaml
@@ -0,0 +1,6 @@
+pr: 128153
+summary: "Fix: Add `NamedWriteable` for `RuleQueryRankDoc`"
+area: Relevance
+type: bug
+issues:
+ - 126071
diff --git a/x-pack/plugin/ent-search/src/main/java/org/elasticsearch/xpack/application/EnterpriseSearch.java b/x-pack/plugin/ent-search/src/main/java/org/elasticsearch/xpack/application/EnterpriseSearch.java
index 0a96672aa2a30..1cdba56db96bf 100644
--- a/x-pack/plugin/ent-search/src/main/java/org/elasticsearch/xpack/application/EnterpriseSearch.java
+++ b/x-pack/plugin/ent-search/src/main/java/org/elasticsearch/xpack/application/EnterpriseSearch.java
@@ -29,6 +29,7 @@
 import org.elasticsearch.plugins.SystemIndexPlugin;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestHandler;
+import org.elasticsearch.search.rank.RankDoc;
 import org.elasticsearch.xcontent.ParseField;
 import org.elasticsearch.xpack.application.analytics.AnalyticsTemplateRegistry;
 import org.elasticsearch.xpack.application.analytics.action.DeleteAnalyticsCollectionAction;
@@ -178,6 +179,7 @@
 import org.elasticsearch.xpack.application.rules.action.TransportPutQueryRulesetAction;
 import org.elasticsearch.xpack.application.rules.action.TransportTestQueryRulesetAction;
 import org.elasticsearch.xpack.application.rules.retriever.QueryRuleRetrieverBuilder;
+import org.elasticsearch.xpack.application.rules.retriever.RuleQueryRankDoc;
 import org.elasticsearch.xpack.application.search.SearchApplicationIndexService;
 import org.elasticsearch.xpack.application.search.action.DeleteSearchApplicationAction;
 import org.elasticsearch.xpack.application.search.action.GetSearchApplicationAction;
@@ -358,6 +360,11 @@ public List<ActionHandler> getActions() {
         return Collections.unmodifiableList(actionHandlers);
     }
 
+    @Override
+    public List<NamedWriteableRegistry.Entry> getNamedWriteables() {
+        return List.of(new NamedWriteableRegistry.Entry(RankDoc.class, RuleQueryRankDoc.NAME, RuleQueryRankDoc::new));
+    }
+
     @Override
     public List<RestHandler> getRestHandlers(
         Settings settings,
diff --git a/x-pack/plugin/ent-search/src/yamlRestTest/resources/rest-api-spec/test/entsearch/rules/40_rule_query_search.yml b/x-pack/plugin/ent-search/src/yamlRestTest/resources/rest-api-spec/test/entsearch/rules/40_rule_query_search.yml
index 56106c66b063f..100b4f1aa4c27 100644
--- a/x-pack/plugin/ent-search/src/yamlRestTest/resources/rest-api-spec/test/entsearch/rules/40_rule_query_search.yml
+++ b/x-pack/plugin/ent-search/src/yamlRestTest/resources/rest-api-spec/test/entsearch/rules/40_rule_query_search.yml
@@ -903,10 +903,18 @@ teardown:
   - do:
       indices.create:
         index: test-index-001
+        body:
+          settings:
+            index:
+              number_of_shards: 5 # Ensure more shards than docs
 
   - do:
       indices.create:
         index: test-index-002
+        body:
+          settings:
+            index:
+              number_of_shards: 5 # Ensure more shards than docs
 
   - do:
       bulk:
@@ -949,6 +957,7 @@ teardown:
 
   - do:
       search:
+        index: test-index-001,test-index-002
         body:
           retriever:
             rule: