feat: Add utility function to escape Unicode characters in tool results

client/src/components/ToolsTab.tsx

@@ -8,15 +8,15 @@ import { Textarea } from "@/components/ui/textarea";
 import DynamicJsonForm, { JsonSchemaType, JsonValue } from "./DynamicJsonForm";
 import { generateDefaultValue } from "@/utils/schemaUtils";
 import {
+  CallToolResultSchema,
+  CompatibilityCallToolResult,
   ListToolsResult,
   Tool,
-  CallToolResultSchema,
 } from "@modelcontextprotocol/sdk/types.js";
 import { AlertCircle, Send } from "lucide-react";
 import { useEffect, useState } from "react";
 import ListPane from "./ListPane";
-
-import { CompatibilityCallToolResult } from "@modelcontextprotocol/sdk/types.js";
+import { escapeUnicode } from "@/utils/escapeUnicode";
 
 const ToolsTab = ({
   tools,
@@ -54,15 +54,15 @@ const ToolsTab = ({
           <>
             <h4 className="font-semibold mb-2">Invalid Tool Result:</h4>
             <pre className="bg-gray-50 dark:bg-gray-800 dark:text-gray-100 p-4 rounded text-sm overflow-auto max-h-64">
-              {JSON.stringify(toolResult, null, 2)}
+              {escapeUnicode(toolResult)}
             </pre>
             <h4 className="font-semibold mb-2">Errors:</h4>
             {parsedResult.error.errors.map((error, idx) => (
               <pre
                 key={idx}
                 className="bg-gray-50 dark:bg-gray-800 dark:text-gray-100 p-4 rounded text-sm overflow-auto max-h-64"
               >
-                {JSON.stringify(error, null, 2)}
+                {escapeUnicode(error)}
               </pre>
             ))}
           </>
@@ -101,7 +101,7 @@ const ToolsTab = ({
                   </audio>
                 ) : (
                   <pre className="bg-gray-50 dark:bg-gray-800 dark:text-gray-100 whitespace-pre-wrap break-words p-4 rounded text-sm overflow-auto max-h-64">
-                    {JSON.stringify(item.resource, null, 2)}
+                    {escapeUnicode(item.resource)}
                   </pre>
                 ))}
             </div>
@@ -113,7 +113,7 @@ const ToolsTab = ({
         <>
           <h4 className="font-semibold mb-2">Tool Result (Legacy):</h4>
           <pre className="bg-gray-50 dark:bg-gray-800 dark:text-gray-100 p-4 rounded text-sm overflow-auto max-h-64">
-            {JSON.stringify(toolResult.toolResult, null, 2)}
+            {escapeUnicode(toolResult.toolResult)}
           </pre>
         </>
       );

client/src/utils/__tests__/escapeUnicode.test.ts

@@ -0,0 +1,27 @@
+import { escapeUnicode } from "../escapeUnicode";
+
+describe("escapeUnicode", () => {
+  it("should escape Unicode characters in a string", () => {
+    const input = { text: "你好世界" };
+    const expected = '{\n  "text": "\\\\u4f60\\\\u597d\\\\u4e16\\\\u754c"\n}';
+    expect(escapeUnicode(input)).toBe(expected);
+  });
+
+  it("should handle empty strings", () => {
+    const input = { text: "" };
+    const expected = '{\n  "text": ""\n}';
+    expect(escapeUnicode(input)).toBe(expected);
+  });
+
+  it("should handle null and undefined values", () => {
+    const input = { text: null, value: undefined };
+    const expected = '{\n  "text": null\n}';
+    expect(escapeUnicode(input)).toBe(expected);
+  });
+
+  it("should handle numbers and booleans", () => {
+    const input = { number: 123, boolean: true };
+    const expected = '{\n  "number": 123,\n  "boolean": true\n}';
+    expect(escapeUnicode(input)).toBe(expected);
+  });
+});

client/src/utils/escapeUnicode.ts

@@ -0,0 +1,16 @@
+// Utility function to escape Unicode characters
+export function escapeUnicode(obj: unknown): string {
+  return JSON.stringify(
+    obj,
+    (_key: string, value) => {
+      if (typeof value === "string") {
+        // Replace non-ASCII characters with their Unicode escape sequences
+        return value.replace(/[^\0-\x7F]/g, (char) => {
+          return "\\u" + ("0000" + char.charCodeAt(0).toString(16)).slice(-4);
+        });
+      }
+      return value;
+    },
+    2,
+  );
+}

package.json

@@ -42,6 +42,7 @@
     "ts-node": "^10.9.2"
   },
   "devDependencies": {
+    "@types/jest": "^29.5.14",
     "@types/node": "^22.7.5",
     "@types/shell-quote": "^1.7.5",
     "prettier": "3.3.3"