diff --git a/x-pack/platform/plugins/shared/observability_solution/observability_ai_assistant/server/service/knowledge_base_service/recall_from_search_connectors.ts b/x-pack/platform/plugins/shared/observability_solution/observability_ai_assistant/server/service/knowledge_base_service/recall_from_search_connectors.ts
index 5abd6d850a8f4..b8a0a7d9267bc 100644
--- a/x-pack/platform/plugins/shared/observability_solution/observability_ai_assistant/server/service/knowledge_base_service/recall_from_search_connectors.ts
+++ b/x-pack/platform/plugins/shared/observability_solution/observability_ai_assistant/server/service/knowledge_base_service/recall_from_search_connectors.ts
@@ -155,12 +155,11 @@ async function recallFromLegacyConnectors({
         bool: {
           should: [
             {
-              text_expansion: {
-                [vectorField]: {
-                  model_text: text,
-                  model_id: modelId,
-                  boost,
-                },
+              sparse_vector: {
+                field: vectorField,
+                query: text,
+                inference_id: modelId,
+                boost,
               },
             },
           ],