diff --git a/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/MLChatAgentRunner.java b/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/MLChatAgentRunner.java
index c5f7c22ed6..c52cd5427c 100644
--- a/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/MLChatAgentRunner.java
+++ b/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/MLChatAgentRunner.java
@@ -701,7 +701,13 @@ private static void runTool(
                         );
                     nextStepListener
                         .onResponse(
-                            String.format(Locale.ROOT, "Failed to run the tool %s with the error message %s.", finalAction, e.getMessage())
+                            String
+                                .format(
+                                    Locale.ROOT,
+                                    "Failed to run the tool %s with the error message %s.",
+                                    finalAction,
+                                    e.getMessage().replaceAll("\\n", "\n")
+                                )
                         );
                 });
                 if (tools.get(action) instanceof MLModelTool) {
diff --git a/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/MLPlanExecuteAndReflectAgentRunner.java b/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/MLPlanExecuteAndReflectAgentRunner.java
index ef12c385c7..0c529b4622 100644
--- a/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/MLPlanExecuteAndReflectAgentRunner.java
+++ b/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/MLPlanExecuteAndReflectAgentRunner.java
@@ -520,6 +520,11 @@ private String extractJsonFromMarkdown(String response) {
             if (response.contains("```")) {
                 response = response.substring(0, response.lastIndexOf("```"));
             }
+        } else {
+            // extract content from {} block
+            if (response.contains("{") && response.contains("}")) {
+                response = response.substring(response.indexOf("{"), response.lastIndexOf("}") + 1);
+            }
         }
 
         response = response.trim();
diff --git a/ml-algorithms/src/main/java/org/opensearch/ml/engine/tools/IndexMappingTool.java b/ml-algorithms/src/main/java/org/opensearch/ml/engine/tools/IndexMappingTool.java
index 3a41dfc2d1..80f497335a 100644
--- a/ml-algorithms/src/main/java/org/opensearch/ml/engine/tools/IndexMappingTool.java
+++ b/ml-algorithms/src/main/java/org/opensearch/ml/engine/tools/IndexMappingTool.java
@@ -95,7 +95,11 @@ public <T> void run(Map<String, String> parameters, ActionListener<T> listener)
         try {
             List<String> indexList = new ArrayList<>();
             if (StringUtils.isNotBlank(parameters.get("index"))) {
-                indexList = gson.fromJson(parameters.get("index"), List.class);
+                try {
+                    indexList = gson.fromJson(parameters.get("index"), List.class);
+                } catch (Exception e) {
+                    indexList.add(parameters.get("index"));
+                }
             }
 
             if (indexList.isEmpty()) {