diff --git a/core/src/main/java/com/google/adk/tools/mcp/AbstractMcpTool.java b/core/src/main/java/com/google/adk/tools/mcp/AbstractMcpTool.java
index 0fcb74846..99d9eb282 100644
--- a/core/src/main/java/com/google/adk/tools/mcp/AbstractMcpTool.java
+++ b/core/src/main/java/com/google/adk/tools/mcp/AbstractMcpTool.java
@@ -22,6 +22,7 @@
 import com.google.adk.tools.BaseTool;
 import com.google.adk.tools.mcp.McpToolException.McpToolDeclarationException;
 import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.genai.types.FunctionDeclaration;
 import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
@@ -31,6 +32,7 @@
 import io.modelcontextprotocol.spec.McpSchema.Tool;
 import io.modelcontextprotocol.spec.McpSchema.ToolAnnotations;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -145,11 +147,14 @@ protected static Map<String, Object> wrapCallResult(
     }
 
     if (textOutputs.isEmpty()) {
-      return ImmutableMap.of(
-          "error",
-          "Tool '" + mcpToolName + "' returned content that is not TextContent.",
-          "content_details",
-          contents.toString());
+      Map<String, Object> result = new HashMap<>();
+      result.put("text_output", ImmutableList.of());
+      result.put("content", contents);
+      result.put("isError", Boolean.FALSE);
+      if (callResult.structuredContent() != null) {
+        result.put("structuredContent", callResult.structuredContent());
+      }
+      return result;
     }
 
     List<Map<String, Object>> resultMaps = new ArrayList<>();
@@ -161,6 +166,13 @@ protected static Map<String, Object> wrapCallResult(
         resultMaps.add(ImmutableMap.of("text", textOutput));
       }
     }
-    return ImmutableMap.of("text_output", resultMaps);
+    Map<String, Object> result = new HashMap<>();
+    result.put("text_output", resultMaps);
+    result.put("content", contents);
+    result.put("isError", Boolean.FALSE);
+    if (callResult.structuredContent() != null) {
+      result.put("structuredContent", callResult.structuredContent());
+    }
+    return result;
   }
 }
diff --git a/core/src/test/java/com/google/adk/tools/mcp/AbstractMcpToolTest.java b/core/src/test/java/com/google/adk/tools/mcp/AbstractMcpToolTest.java
index 4c633c660..4859512eb 100644
--- a/core/src/test/java/com/google/adk/tools/mcp/AbstractMcpToolTest.java
+++ b/core/src/test/java/com/google/adk/tools/mcp/AbstractMcpToolTest.java
@@ -25,6 +25,7 @@
 import io.modelcontextprotocol.client.McpSyncClient;
 import io.modelcontextprotocol.spec.McpSchema;
 import io.modelcontextprotocol.spec.McpSchema.CallToolResult;
+import io.modelcontextprotocol.spec.McpSchema.ImageContent;
 import io.modelcontextprotocol.spec.McpSchema.TextContent;
 import java.util.List;
 import java.util.Map;
@@ -61,6 +62,43 @@ public void testWrapCallResult_success() {
     assertThat(contentItem).containsEntry("text", "success");
   }
 
+  @Test
+  public void testWrapCallResult_preservesCompleteSuccessfulResult() {
+    Map<String, Object> structuredContent = Map.of("count", 2);
+    CallToolResult result =
+        CallToolResult.builder()
+            .content(
+                ImmutableList.of(
+                    new TextContent("first"),
+                    new ImageContent("aW1hZ2U=", "image/png")))
+            .structuredContent(structuredContent)
+            .isError(false)
+            .build();
+
+    Map<String, Object> map = AbstractMcpTool.wrapCallResult(objectMapper, "my_tool", result);
+
+    assertThat(map).containsEntry("isError", false);
+    assertThat(map).containsEntry("structuredContent", structuredContent);
+    assertThat((List<?>) map.get("content")).hasSize(2);
+    assertThat(map).containsKey("text_output");
+  }
+
+  @Test
+  public void testWrapCallResult_preservesSuccessfulNonTextResult() {
+    CallToolResult result =
+        CallToolResult.builder()
+            .content(ImmutableList.of(new ImageContent("aW1hZ2U=", "image/png")))
+            .isError(false)
+            .build();
+
+    Map<String, Object> map = AbstractMcpTool.wrapCallResult(objectMapper, "my_tool", result);
+
+    assertThat(map).containsEntry("isError", false);
+    assertThat((List<?>) map.get("content")).hasSize(1);
+    assertThat((List<?>) map.get("text_output")).isEmpty();
+    assertThat(map).doesNotContainKey("error");
+  }
+
   @Test
   public void instantiateWithToolBuilder_nullDescription_succeeds() {
     McpSyncClient sessionMock = mock(McpSyncClient.class);