diff --git a/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/AgentUtils.java b/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/AgentUtils.java
index d8f8d6da94..8d01c59bf2 100644
--- a/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/AgentUtils.java
+++ b/ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/agent/AgentUtils.java
@@ -60,6 +60,7 @@ public class AgentUtils {
     public static final String PROMPT_CHAT_HISTORY_PREFIX = "prompt.chat_history_prefix";
     public static final String DISABLE_TRACE = "disable_trace";
     public static final String VERBOSE = "verbose";
+    public static final String LLM_GEN_INPUT = "llm_generated_input";
 
     public static String addExamplesToPrompt(Map<String, String> parameters, String prompt) {
         Map<String, String> examplesMap = new HashMap<>();
@@ -472,6 +473,11 @@ public static Map<String, String> constructToolParams(
         if (toolSpecConfigMap != null) {
             toolParams.putAll(toolSpecConfigMap);
         }
+        toolParams.put(LLM_GEN_INPUT, actionInput);
+        if (isJson(actionInput)) {
+            Map<String, String> params = getParameterMap(gson.fromJson(actionInput, Map.class));
+            toolParams.putAll(params);
+        }
         if (tools.get(action).useOriginalInput()) {
             toolParams.put("input", question);
             lastActionInput.set(question);
@@ -486,10 +492,6 @@ public static Map<String, String> constructToolParams(
             }
         } else {
             toolParams.put("input", actionInput);
-            if (isJson(actionInput)) {
-                Map<String, String> params = getParameterMap(gson.fromJson(actionInput, Map.class));
-                toolParams.putAll(params);
-            }
         }
         return toolParams;
     }
diff --git a/ml-algorithms/src/test/java/org/opensearch/ml/engine/algorithms/agent/AgentUtilsTest.java b/ml-algorithms/src/test/java/org/opensearch/ml/engine/algorithms/agent/AgentUtilsTest.java
index 496ce00136..c2bf05205a 100644
--- a/ml-algorithms/src/test/java/org/opensearch/ml/engine/algorithms/agent/AgentUtilsTest.java
+++ b/ml-algorithms/src/test/java/org/opensearch/ml/engine/algorithms/agent/AgentUtilsTest.java
@@ -8,6 +8,7 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThrows;
 import static org.mockito.Mockito.when;
+import static org.opensearch.ml.engine.algorithms.agent.AgentUtils.LLM_GEN_INPUT;
 import static org.opensearch.ml.engine.algorithms.agent.AgentUtils.PROMPT_PREFIX;
 import static org.opensearch.ml.engine.algorithms.agent.AgentUtils.PROMPT_SUFFIX;
 import static org.opensearch.ml.engine.algorithms.agent.MLChatAgentRunner.ACTION;
@@ -603,11 +604,24 @@ public void testConstructToolParams() {
         String question = "dummy question";
         String actionInput = "{'detectorName': 'abc', 'indices': 'sample-data' }";
         verifyConstructToolParams(question, actionInput, (toolParams) -> {
-            Assert.assertEquals(4, toolParams.size());
+            Assert.assertEquals(5, toolParams.size());
             Assert.assertEquals(actionInput, toolParams.get("input"));
             Assert.assertEquals("abc", toolParams.get("detectorName"));
             Assert.assertEquals("sample-data", toolParams.get("indices"));
             Assert.assertEquals("value1", toolParams.get("key1"));
+            Assert.assertEquals(actionInput, toolParams.get(LLM_GEN_INPUT));
+        });
+    }
+
+    @Test
+    public void testConstructToolParamsNullActionInput() {
+        String question = "dummy question";
+        String actionInput = null;
+        verifyConstructToolParams(question, actionInput, (toolParams) -> {
+            Assert.assertEquals(3, toolParams.size());
+            Assert.assertEquals("value1", toolParams.get("key1"));
+            Assert.assertNull(toolParams.get(LLM_GEN_INPUT));
+            Assert.assertNull(toolParams.get("input"));
         });
     }
 
@@ -617,12 +631,65 @@ public void testConstructToolParams_UseOriginalInput() {
         String actionInput = "{'detectorName': 'abc', 'indices': 'sample-data' }";
         when(tool1.useOriginalInput()).thenReturn(true);
         verifyConstructToolParams(question, actionInput, (toolParams) -> {
-            Assert.assertEquals(2, toolParams.size());
+            Assert.assertEquals(5, toolParams.size());
             Assert.assertEquals(question, toolParams.get("input"));
             Assert.assertEquals("value1", toolParams.get("key1"));
+            Assert.assertEquals(actionInput, toolParams.get(LLM_GEN_INPUT));
+            Assert.assertEquals("sample-data", toolParams.get("indices"));
+            Assert.assertEquals("abc", toolParams.get("detectorName"));
         });
     }
 
+    @Test
+    public void testConstructToolParams_PlaceholderConfigInput() {
+        String question = "dummy question";
+        String actionInput = "action input";
+        String preConfigInputStr = "Config Input: ";
+        Map<String, Tool> tools = Map.of("tool1", tool1);
+        Map<String, MLToolSpec> toolSpecMap = Map
+            .of(
+                "tool1",
+                MLToolSpec
+                    .builder()
+                    .type("tool1")
+                    .parameters(Map.of("key1", "value1"))
+                    .configMap(Map.of("input", preConfigInputStr + "${parameters.llm_generated_input}"))
+                    .build()
+            );
+        AtomicReference<String> lastActionInput = new AtomicReference<>();
+        String action = "tool1";
+        Map<String, String> toolParams = AgentUtils.constructToolParams(tools, toolSpecMap, question, lastActionInput, action, actionInput);
+        Assert.assertEquals(3, toolParams.size());
+        Assert.assertEquals(preConfigInputStr + actionInput, toolParams.get("input"));
+        Assert.assertEquals("value1", toolParams.get("key1"));
+        Assert.assertEquals(actionInput, toolParams.get(LLM_GEN_INPUT));
+    }
+
+    @Test
+    public void testConstructToolParams_PlaceholderConfigInputJson() {
+        String question = "dummy question";
+        String actionInput = "{'detectorName': 'abc', 'indices': 'sample-data' }";
+        String preConfigInputStr = "Config Input: ";
+        Map<String, Tool> tools = Map.of("tool1", tool1);
+        Map<String, MLToolSpec> toolSpecMap = Map
+            .of(
+                "tool1",
+                MLToolSpec
+                    .builder()
+                    .type("tool1")
+                    .parameters(Map.of("key1", "value1"))
+                    .configMap(Map.of("input", preConfigInputStr + "${parameters.detectorName}"))
+                    .build()
+            );
+        AtomicReference<String> lastActionInput = new AtomicReference<>();
+        String action = "tool1";
+        Map<String, String> toolParams = AgentUtils.constructToolParams(tools, toolSpecMap, question, lastActionInput, action, actionInput);
+        Assert.assertEquals(5, toolParams.size());
+        Assert.assertEquals(preConfigInputStr + "abc", toolParams.get("input"));
+        Assert.assertEquals("value1", toolParams.get("key1"));
+        Assert.assertEquals(actionInput, toolParams.get(LLM_GEN_INPUT));
+    }
+
     private void verifyConstructToolParams(String question, String actionInput, Consumer<Map<String, String>> verify) {
         Map<String, Tool> tools = Map.of("tool1", tool1);
         Map<String, MLToolSpec> toolSpecMap = Map
diff --git a/ml-algorithms/src/test/java/org/opensearch/ml/engine/algorithms/agent/MLChatAgentRunnerTest.java b/ml-algorithms/src/test/java/org/opensearch/ml/engine/algorithms/agent/MLChatAgentRunnerTest.java
index 5044d0a506..41982abe5b 100644
--- a/ml-algorithms/src/test/java/org/opensearch/ml/engine/algorithms/agent/MLChatAgentRunnerTest.java
+++ b/ml-algorithms/src/test/java/org/opensearch/ml/engine/algorithms/agent/MLChatAgentRunnerTest.java
@@ -706,7 +706,7 @@ public void testToolParameters() {
         // Verify the size of parameters passed in the tool run method.
         ArgumentCaptor argumentCaptor = ArgumentCaptor.forClass(Map.class);
         verify(firstTool).run((Map<String, String>) argumentCaptor.capture(), any());
-        assertEquals(14, ((Map) argumentCaptor.getValue()).size());
+        assertEquals(15, ((Map) argumentCaptor.getValue()).size());
 
         Mockito.verify(agentActionListener).onResponse(objectCaptor.capture());
         ModelTensorOutput modelTensorOutput = (ModelTensorOutput) objectCaptor.getValue();
@@ -734,7 +734,7 @@ public void testToolUseOriginalInput() {
         // Verify the size of parameters passed in the tool run method.
         ArgumentCaptor argumentCaptor = ArgumentCaptor.forClass(Map.class);
         verify(firstTool).run((Map<String, String>) argumentCaptor.capture(), any());
-        assertEquals(15, ((Map) argumentCaptor.getValue()).size());
+        assertEquals(16, ((Map) argumentCaptor.getValue()).size());
         assertEquals("raw input", ((Map<?, ?>) argumentCaptor.getValue()).get("input"));
 
         Mockito.verify(agentActionListener).onResponse(objectCaptor.capture());
@@ -763,7 +763,7 @@ public void testToolConfig() {
         // Verify the size of parameters passed in the tool run method.
         ArgumentCaptor argumentCaptor = ArgumentCaptor.forClass(Map.class);
         verify(firstTool).run((Map<String, String>) argumentCaptor.capture(), any());
-        assertEquals(15, ((Map) argumentCaptor.getValue()).size());
+        assertEquals(16, ((Map) argumentCaptor.getValue()).size());
         // The value of input should be "config_value".
         assertEquals("config_value", ((Map<?, ?>) argumentCaptor.getValue()).get("input"));
 
@@ -793,7 +793,7 @@ public void testToolConfigWithInputPlaceholder() {
         // Verify the size of parameters passed in the tool run method.
         ArgumentCaptor argumentCaptor = ArgumentCaptor.forClass(Map.class);
         verify(firstTool).run((Map<String, String>) argumentCaptor.capture(), any());
-        assertEquals(15, ((Map) argumentCaptor.getValue()).size());
+        assertEquals(16, ((Map) argumentCaptor.getValue()).size());
         // The value of input should be replaced with the value associated with the key "key2" of the first tool.
         assertEquals("value2", ((Map<?, ?>) argumentCaptor.getValue()).get("input"));