diff --git a/client/src/components/History.tsx b/client/src/components/History.tsx
index 532d3b1..7ce7dcf 100644
--- a/client/src/components/History.tsx
+++ b/client/src/components/History.tsx
@@ -1,6 +1,7 @@
 import { ServerNotification } from "@modelcontextprotocol/sdk/types.js";
 import { Copy } from "lucide-react";
 import { useState } from "react";
+import JsonView from "./JsonView";
 
 const HistoryAndNotifications = ({
   requestHistory,
@@ -75,7 +76,7 @@ const HistoryAndNotifications = ({
                           </button>
                         </div>
                         <pre className="whitespace-pre-wrap break-words bg-background p-2 rounded">
-                          {JSON.stringify(JSON.parse(request.request), null, 2)}
+                          <JsonView data={request.request} />
                         </pre>
                       </div>
                       {request.response && (
@@ -92,11 +93,7 @@ const HistoryAndNotifications = ({
                             </button>
                           </div>
                           <pre className="whitespace-pre-wrap break-words bg-background p-2 rounded">
-                            {JSON.stringify(
-                              JSON.parse(request.response),
-                              null,
-                              2,
-                            )}
+                            <JsonView data={request.response} />
                           </pre>
                         </div>
                       )}
@@ -147,7 +144,9 @@ const HistoryAndNotifications = ({
                         </button>
                       </div>
                       <pre className="whitespace-pre-wrap break-words bg-background p-2 rounded">
-                        {JSON.stringify(notification, null, 2)}
+                        <JsonView
+                          data={JSON.stringify(notification, null, 2)}
+                        />
                       </pre>
                     </div>
                   )}
diff --git a/client/src/components/JsonView.tsx b/client/src/components/JsonView.tsx
new file mode 100644
index 0000000..21d65d8
--- /dev/null
+++ b/client/src/components/JsonView.tsx
@@ -0,0 +1,210 @@
+import { useState, memo } from "react";
+import { JsonValue } from "./DynamicJsonForm";
+
+interface JsonViewProps {
+  data: JsonValue;
+  name?: string;
+  initialExpandDepth?: number;
+}
+
+function tryParseJson(str: string): { success: boolean; data: JsonValue } {
+  const trimmed = str.trim();
+  if (
+    !(trimmed.startsWith("{") && trimmed.endsWith("}")) &&
+    !(trimmed.startsWith("[") && trimmed.endsWith("]"))
+  ) {
+    return { success: false, data: str };
+  }
+  try {
+    return { success: true, data: JSON.parse(str) };
+  } catch {
+    return { success: false, data: str };
+  }
+}
+
+const JsonView = memo(
+  ({ data, name, initialExpandDepth = 2 }: JsonViewProps) => {
+    const normalizedData =
+      typeof data === "string"
+        ? tryParseJson(data).success
+          ? tryParseJson(data).data
+          : data
+        : data;
+
+    return (
+      <div className="font-mono text-sm transition-all duration-300">
+        <JsonNode
+          data={normalizedData}
+          name={name}
+          depth={0}
+          initialExpandDepth={initialExpandDepth}
+        />
+      </div>
+    );
+  },
+);
+
+JsonView.displayName = "JsonView";
+
+interface JsonNodeProps {
+  data: JsonValue;
+  name?: string;
+  depth: number;
+  initialExpandDepth: number;
+}
+
+const JsonNode = memo(
+  ({ data, name, depth = 0, initialExpandDepth }: JsonNodeProps) => {
+    const [isExpanded, setIsExpanded] = useState(depth < initialExpandDepth);
+
+    const getDataType = (value: JsonValue): string => {
+      if (Array.isArray(value)) return "array";
+      if (value === null) return "null";
+      return typeof value;
+    };
+
+    const dataType = getDataType(data);
+
+    const typeStyleMap: Record<string, string> = {
+      number: "text-blue-600",
+      boolean: "text-amber-600",
+      null: "text-purple-600",
+      undefined: "text-gray-600",
+      string: "text-green-600",
+      default: "text-gray-700",
+    };
+
+    const renderCollapsible = (isArray: boolean) => {
+      const items = isArray
+        ? (data as JsonValue[])
+        : Object.entries(data as Record<string, JsonValue>);
+      const itemCount = items.length;
+      const isEmpty = itemCount === 0;
+
+      const symbolMap = {
+        open: isArray ? "[" : "{",
+        close: isArray ? "]" : "}",
+        collapsed: isArray ? "[ ... ]" : "{ ... }",
+        empty: isArray ? "[]" : "{}",
+      };
+
+      if (isEmpty) {
+        return (
+          <div className="flex items-center">
+            {name && <span className="mr-1 text-gray-400">{name}:</span>}
+            <span className="text-gray-500">{symbolMap.empty}</span>
+          </div>
+        );
+      }
+
+      return (
+        <div className="flex flex-col">
+          <div
+            className="flex items-center mr-1 rounded cursor-pointer group hover:bg-gray-800/20"
+            onClick={() => setIsExpanded(!isExpanded)}
+          >
+            {name && (
+              <span className="mr-1 text-gray-400 group-hover:text-gray-100">
+                {name}:
+              </span>
+            )}
+            {isExpanded ? (
+              <span className="text-gray-400 group-hover:text-gray-100">
+                {symbolMap.open}
+              </span>
+            ) : (
+              <>
+                <span className="text-gray-600 group-hover:text-gray-100">
+                  {symbolMap.collapsed}
+                </span>
+                <span className="ml-1 text-gray-700 group-hover:text-gray-100">
+                  {itemCount} {itemCount === 1 ? "item" : "items"}
+                </span>
+              </>
+            )}
+          </div>
+          {isExpanded && (
+            <>
+              <div className="pl-2 ml-4 border-l border-gray-800">
+                {isArray
+                  ? (items as JsonValue[]).map((item, index) => (
+                      <div key={index} className="my-1">
+                        <JsonNode
+                          data={item}
+                          name={`${index}`}
+                          depth={depth + 1}
+                          initialExpandDepth={initialExpandDepth}
+                        />
+                      </div>
+                    ))
+                  : (items as [string, JsonValue][]).map(([key, value]) => (
+                      <div key={key} className="my-1">
+                        <JsonNode
+                          data={value}
+                          name={key}
+                          depth={depth + 1}
+                          initialExpandDepth={initialExpandDepth}
+                        />
+                      </div>
+                    ))}
+              </div>
+              <div className="text-gray-400">{symbolMap.close}</div>
+            </>
+          )}
+        </div>
+      );
+    };
+
+    const renderString = (value: string) => {
+      const maxLength = 100;
+      const isTooLong = value.length > maxLength;
+
+      if (!isTooLong) {
+        return (
+          <div className="flex mr-1 rounded hover:bg-gray-800/20">
+            {name && <span className="mr-1 text-gray-400">{name}:</span>}
+            <span className={typeStyleMap.string}>"{value}"</span>
+          </div>
+        );
+      }
+
+      return (
+        <div className="flex mr-1 rounded group hover:bg-gray-800/20">
+          {name && (
+            <span className="mr-1 text-gray-400 group-hover:text-gray-100">
+              {name}:
+            </span>
+          )}
+          <span
+            className={`${typeStyleMap.string} cursor-pointer group-hover:text-green-500`}
+            onClick={() => setIsExpanded(!isExpanded)}
+            title={isExpanded ? "클릭하여 축소" : "클릭하여 전체 보기"}
+          >
+            {isExpanded ? `"${value}"` : `"${value.slice(0, maxLength)}..."`}
+          </span>
+        </div>
+      );
+    };
+
+    switch (dataType) {
+      case "object":
+      case "array":
+        return renderCollapsible(dataType === "array");
+      case "string":
+        return renderString(data as string);
+      default:
+        return (
+          <div className="flex items-center mr-1 rounded hover:bg-gray-800/20">
+            {name && <span className="mr-1 text-gray-400">{name}:</span>}
+            <span className={typeStyleMap[dataType] || typeStyleMap.default}>
+              {data === null ? "null" : String(data)}
+            </span>
+          </div>
+        );
+    }
+  },
+);
+
+JsonNode.displayName = "JsonNode";
+
+export default JsonView;
diff --git a/client/src/components/ResourcesTab.tsx b/client/src/components/ResourcesTab.tsx
index f000840..bc3e39a 100644
--- a/client/src/components/ResourcesTab.tsx
+++ b/client/src/components/ResourcesTab.tsx
@@ -15,6 +15,7 @@ import { AlertCircle, ChevronRight, FileText, RefreshCw } from "lucide-react";
 import ListPane from "./ListPane";
 import { useEffect, useState } from "react";
 import { useCompletionState } from "@/lib/hooks/useCompletionState";
+import JsonView from "./JsonView";
 
 const ResourcesTab = ({
   resources,
@@ -215,7 +216,7 @@ const ResourcesTab = ({
             </Alert>
           ) : selectedResource ? (
             <pre className="bg-gray-50 dark:bg-gray-800 p-4 rounded text-sm overflow-auto max-h-96 whitespace-pre-wrap break-words text-gray-900 dark:text-gray-100">
-              {resourceContent}
+              <JsonView data={resourceContent} />
             </pre>
           ) : selectedTemplate ? (
             <div className="space-y-4">
diff --git a/client/src/components/SamplingTab.tsx b/client/src/components/SamplingTab.tsx
index 5c45400..d14d4c8 100644
--- a/client/src/components/SamplingTab.tsx
+++ b/client/src/components/SamplingTab.tsx
@@ -5,6 +5,7 @@ import {
   CreateMessageRequest,
   CreateMessageResult,
 } from "@modelcontextprotocol/sdk/types.js";
+import JsonView from "./JsonView";
 
 export type PendingRequest = {
   id: number;
@@ -44,7 +45,7 @@ const SamplingTab = ({ pendingRequests, onApprove, onReject }: Props) => {
         {pendingRequests.map((request) => (
           <div key={request.id} className="p-4 border rounded-lg space-y-4">
             <pre className="bg-gray-50 dark:bg-gray-800 dark:text-gray-100 p-2 rounded">
-              {JSON.stringify(request.request, null, 2)}
+              <JsonView data={JSON.stringify(request.request)} />
             </pre>
             <div className="flex space-x-2">
               <Button onClick={() => handleApprove(request.id)}>Approve</Button>
diff --git a/client/src/components/ToolsTab.tsx b/client/src/components/ToolsTab.tsx
index 82ebdb0..345f7bd 100644
--- a/client/src/components/ToolsTab.tsx
+++ b/client/src/components/ToolsTab.tsx
@@ -17,6 +17,7 @@ import { AlertCircle, Send } from "lucide-react";
 import { useEffect, useState } from "react";
 import ListPane from "./ListPane";
 import { escapeUnicode } from "@/utils/escapeUnicode";
+import JsonView from "./JsonView";
 
 const ToolsTab = ({
   tools,
@@ -54,7 +55,7 @@ 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">
-              {escapeUnicode(toolResult)}
+              <JsonView data={escapeUnicode(toolResult)} />
             </pre>
             <h4 className="font-semibold mb-2">Errors:</h4>
             {parsedResult.error.errors.map((error, idx) => (
@@ -62,7 +63,7 @@ const ToolsTab = ({
                 key={idx}
                 className="bg-gray-50 dark:bg-gray-800 dark:text-gray-100 p-4 rounded text-sm overflow-auto max-h-64"
               >
-                {escapeUnicode(error)}
+                <JsonView data={escapeUnicode(error)} />
               </pre>
             ))}
           </>
@@ -80,7 +81,7 @@ const ToolsTab = ({
             <div key={index} className="mb-2">
               {item.type === "text" && (
                 <pre className="bg-gray-50 dark:bg-gray-800 dark:text-gray-100 p-4 rounded text-sm overflow-auto max-h-64">
-                  {item.text}
+                  <JsonView data={item.text} />
                 </pre>
               )}
               {item.type === "image" && (
@@ -101,7 +102,7 @@ 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">
-                    {escapeUnicode(item.resource)}
+                    <JsonView data={escapeUnicode(item.resource)} />
                   </pre>
                 ))}
             </div>
@@ -113,7 +114,7 @@ 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">
-            {escapeUnicode(toolResult.toolResult)}
+            <JsonView data={escapeUnicode(toolResult.toolResult)} />
           </pre>
         </>
       );