Add rag utility

src/main/java/mcp/tools/McpValidatedTool.java

@@ -66,6 +66,17 @@ public abstract class McpValidatedTool implements McpTool {
         return new CallToolResultBuilder().addText(text).build();
     }
 
+    protected McpSchema.CallToolResult success(String text, Map<String, Object> structured) {
+        return new CallToolResultBuilder()
+                .addText(text)
+                .structuredContent(structured)
+                .build();
+    }
+
+    protected McpSchema.CallToolResult successResult(Object resultValue) {
+        return success(String.valueOf(resultValue), Map.of("result", resultValue));
+    }
+
     protected McpSchema.CallToolResult error(String text) {
         return new CallToolResultBuilder().isError(true).addText(text).build();
     }