diff --git a/cptr/frontend/src/lib/components/Admin/Models.svelte b/cptr/frontend/src/lib/components/Admin/Models.svelte
index 49229c1..234a8d8 100644
--- a/cptr/frontend/src/lib/components/Admin/Models.svelte
+++ b/cptr/frontend/src/lib/components/Admin/Models.svelte
@@ -4,6 +4,8 @@
 	import {
 		getModelConfig,
 		updateModelConfig,
+		getAdminConfig,
+		updateConfig,
 		type ModelConfigEntry
 	} from '$lib/apis/admin';
 	import { t } from '$lib/i18n';
@@ -32,6 +34,10 @@
 	let globalExpanded = $state(false);
 	let showVariables = $state(false);
 
+	// Context compaction
+	let compactTokenThreshold = $state(80000);
+	let compactDirty = $state(false);
+
 	const TEMPLATE_VARIABLES = [
 		{ name: 'WORKSPACE_NAME', desc: 'Workspace folder name' },
 		{ name: 'WORKSPACE_PATH', desc: 'Full workspace path' },
@@ -52,7 +58,7 @@ Workspace: {{WORKSPACE_NAME}}
 Files:
 {{FILE_TREE}}`;
 
-	let hasDirty = $derived(globalDirty || models.some((m) => m.dirty));
+	let hasDirty = $derived(globalDirty || compactDirty || models.some((m) => m.dirty));
 
 	function parseRows(config: ModelConfigEntry | undefined): ParamRow[] {
 		const rp = config?.params?.request_params;
@@ -98,6 +104,12 @@ Files:
 		} finally {
 			loading = false;
 		}
+
+		// Load context compaction threshold from admin config
+		try {
+			const adminCfg = await getAdminConfig();
+			compactTokenThreshold = Number(adminCfg['chat.compact_token_threshold']) || 80000;
+		} catch {}
 	});
 
 	async function toggleModel(e: Event, model: ModelEntry) {
@@ -145,6 +157,13 @@ Files:
 			await Promise.all(promises);
 			globalDirty = false;
 			models.forEach((m) => (m.dirty = false));
+
+			// Save context compaction threshold
+			if (compactDirty) {
+				await updateConfig({ 'chat.compact_token_threshold': compactTokenThreshold });
+				compactDirty = false;
+			}
+
 			toast.success($t('settings.saved'));
 		} catch {
 			toast.error($t('models.failedToSave'));
@@ -256,6 +275,24 @@ Files:
 			<h2 class="text-sm font-medium text-gray-900 dark:text-white mb-4">
 				{$t('admin.models')}
 			</h2>
+
+			<!-- Context compaction -->
+			<h3 class="text-xs text-gray-400 dark:text-gray-600 mb-2">{$t('admin.contextCompaction')}</h3>
+
+			<div class="flex flex-col gap-2.5 mb-5">
+				<div>
+					<label class="text-xs text-gray-600 dark:text-gray-400" for="compact-threshold">{$t('admin.compactTokenThreshold')}</label>
+					<div class="flex items-center gap-1.5 mt-1">
+						<input id="compact-threshold" type="number" bind:value={compactTokenThreshold}
+							oninput={() => (compactDirty = true)}
+							min="10000" max="1000000" step="10000"
+							class="w-24 h-7 px-2 rounded-lg text-xs bg-gray-100 dark:bg-white/6 text-gray-700 dark:text-gray-300 border border-gray-200 dark:border-white/8 outline-none focus:border-blue-400 dark:focus:border-blue-500 transition-colors" />
+						<span class="text-[11px] text-gray-400 dark:text-gray-600">{$t('admin.compactTokenThresholdUnit')}</span>
+					</div>
+					<p class="text-[11px] text-gray-400 dark:text-gray-600 mt-0.5">{$t('admin.compactTokenThresholdHint')}</p>
+				</div>
+			</div>
+
 			<!-- Global defaults -->
 			<button
 				class="group flex items-center gap-2 w-full h-7 text-left"
diff --git a/cptr/frontend/src/lib/i18n/locales/de.json b/cptr/frontend/src/lib/i18n/locales/de.json
index 01656a8..bc5e2ae 100644
--- a/cptr/frontend/src/lib/i18n/locales/de.json
+++ b/cptr/frontend/src/lib/i18n/locales/de.json
@@ -569,5 +569,17 @@
 	"admin.gateway.newKey": "Neuer API-Schlüssel erstellt. Jetzt kopieren",
 	"admin.gateway.noKeys": "Noch keine API-Schlüssel",
 	"admin.gateway.title": "API-Gateway",
-	"chat.greeting": "Wie kann ich Ihnen helfen?"
+	"chat.greeting": "Wie kann ich Ihnen helfen?",
+
+	"admin.subagents": "Sub-Agenten",
+	"admin.subagentsEnabled": "Sub-Agenten aktivieren",
+	"admin.subagentsHint": "Ermöglicht der KI, Aufgaben an Sub-Agenten zu delegieren. Jeder Sub-Agent erstellt einen echten Chat mit vollem Werkzeugzugriff. Verwendet zusätzliche LLM-Aufrufe.",
+	"admin.subagentsMaxConcurrent": "Max. gleichzeitig",
+	"admin.subagentsMaxConcurrentHint": "gleichzeitige Sub-Agenten",
+	"admin.subagentsMaxIterations": "Max. Iterationen",
+	"admin.subagentsMaxIterationsHint": "Werkzeugschleifen pro Sub-Agent",
+	"admin.subagentsMaxOutput": "Max. Ausgabe",
+	"admin.subagentsSystemPrompt": "System-Prompt",
+	"admin.subagentsSystemPromptPlaceholder": "Du bist ein Sub-Agent...",
+	"admin.subagentsSystemPromptHint": "Leer lassen für den integrierten Standard."
 }
diff --git a/cptr/frontend/src/lib/i18n/locales/en.json b/cptr/frontend/src/lib/i18n/locales/en.json
index ec0c45b..fc3c248 100644
--- a/cptr/frontend/src/lib/i18n/locales/en.json
+++ b/cptr/frontend/src/lib/i18n/locales/en.json
@@ -692,6 +692,11 @@
 	"admin.subagentsMaxOutput": "Max output",
 	"admin.subagentsSystemPrompt": "System prompt",
 	"admin.subagentsSystemPromptPlaceholder": "You are a sub-agent...",
-	"admin.subagentsSystemPromptHint": "Leave empty for the built-in default."
+	"admin.subagentsSystemPromptHint": "Leave empty for the built-in default.",
+
+	"admin.contextCompaction": "Context compaction",
+	"admin.compactTokenThreshold": "Token threshold",
+	"admin.compactTokenThresholdUnit": "tokens",
+	"admin.compactTokenThresholdHint": "Older messages are summarized when estimated context exceeds this limit. Default: 80,000."
 }
 
diff --git a/cptr/frontend/src/lib/i18n/locales/es.json b/cptr/frontend/src/lib/i18n/locales/es.json
index 9444620..5e69a66 100644
--- a/cptr/frontend/src/lib/i18n/locales/es.json
+++ b/cptr/frontend/src/lib/i18n/locales/es.json
@@ -569,5 +569,17 @@
 	"admin.gateway.newKey": "Nueva clave API creada. Cópiala ahora",
 	"admin.gateway.noKeys": "Aún no hay claves API",
 	"admin.gateway.title": "API Gateway",
-	"chat.greeting": "¿En qué puedo ayudarte?"
+	"chat.greeting": "¿En qué puedo ayudarte?",
+
+	"admin.subagents": "Sub-agentes",
+	"admin.subagentsEnabled": "Habilitar sub-agentes",
+	"admin.subagentsHint": "Permite a la IA delegar tareas a sub-agentes. Cada sub-agente crea un chat real con acceso completo a herramientas. Usa llamadas LLM adicionales.",
+	"admin.subagentsMaxConcurrent": "Máx. simultáneos",
+	"admin.subagentsMaxConcurrentHint": "sub-agentes simultáneos",
+	"admin.subagentsMaxIterations": "Máx. iteraciones",
+	"admin.subagentsMaxIterationsHint": "bucles de herramientas por sub-agente",
+	"admin.subagentsMaxOutput": "Máx. salida",
+	"admin.subagentsSystemPrompt": "Prompt del sistema",
+	"admin.subagentsSystemPromptPlaceholder": "Eres un sub-agente...",
+	"admin.subagentsSystemPromptHint": "Dejar vacío para el valor predeterminado."
 }
diff --git a/cptr/frontend/src/lib/i18n/locales/fr.json b/cptr/frontend/src/lib/i18n/locales/fr.json
index 3af1263..a9fb176 100644
--- a/cptr/frontend/src/lib/i18n/locales/fr.json
+++ b/cptr/frontend/src/lib/i18n/locales/fr.json
@@ -568,5 +568,17 @@
 	"admin.gateway.newKey": "Nouvelle clé API créée. Copiez-la maintenant",
 	"admin.gateway.noKeys": "Aucune clé API",
 	"admin.gateway.title": "Passerelle API",
-	"chat.greeting": "Comment puis-je vous aider ?"
+	"chat.greeting": "Comment puis-je vous aider ?",
+
+	"admin.subagents": "Sous-agents",
+	"admin.subagentsEnabled": "Activer les sous-agents",
+	"admin.subagentsHint": "Permet à l'IA de déléguer des tâches à des sous-agents. Chaque sous-agent crée un vrai chat avec un accès complet aux outils. Utilise des appels LLM supplémentaires.",
+	"admin.subagentsMaxConcurrent": "Max. simultanés",
+	"admin.subagentsMaxConcurrentHint": "sous-agents simultanés",
+	"admin.subagentsMaxIterations": "Max. itérations",
+	"admin.subagentsMaxIterationsHint": "boucles d'outils par sous-agent",
+	"admin.subagentsMaxOutput": "Max. sortie",
+	"admin.subagentsSystemPrompt": "Prompt système",
+	"admin.subagentsSystemPromptPlaceholder": "Vous êtes un sous-agent...",
+	"admin.subagentsSystemPromptHint": "Laisser vide pour la valeur par défaut."
 }
diff --git a/cptr/frontend/src/lib/i18n/locales/ja.json b/cptr/frontend/src/lib/i18n/locales/ja.json
index 71b5bbe..9db4828 100644
--- a/cptr/frontend/src/lib/i18n/locales/ja.json
+++ b/cptr/frontend/src/lib/i18n/locales/ja.json
@@ -569,5 +569,17 @@
 	"admin.gateway.newKey": "新しいAPIキーが作成されました。今すぐコピーしてください",
 	"admin.gateway.noKeys": "APIキーがまだありません",
 	"admin.gateway.title": "APIゲートウェイ",
-	"chat.greeting": "何かお手伝いできますか？"
+	"chat.greeting": "何かお手伝いできますか？",
+
+	"admin.subagents": "サブエージェント",
+	"admin.subagentsEnabled": "サブエージェントを有効にする",
+	"admin.subagentsHint": "AIがサブエージェントにタスクを委任できるようにします。各サブエージェントはフルツールアクセス付きの実際のチャットを作成します。追加のLLMコールを使用します。",
+	"admin.subagentsMaxConcurrent": "最大同時実行数",
+	"admin.subagentsMaxConcurrentHint": "同時実行サブエージェント",
+	"admin.subagentsMaxIterations": "最大反復回数",
+	"admin.subagentsMaxIterationsHint": "サブエージェントあたりのツールループ",
+	"admin.subagentsMaxOutput": "最大出力",
+	"admin.subagentsSystemPrompt": "システムプロンプト",
+	"admin.subagentsSystemPromptPlaceholder": "あなたはサブエージェントです...",
+	"admin.subagentsSystemPromptHint": "組み込みデフォルトを使用する場合は空のままにしてください。"
 }
diff --git a/cptr/frontend/src/lib/i18n/locales/ko.json b/cptr/frontend/src/lib/i18n/locales/ko.json
index 29d934e..4055b37 100644
--- a/cptr/frontend/src/lib/i18n/locales/ko.json
+++ b/cptr/frontend/src/lib/i18n/locales/ko.json
@@ -569,5 +569,17 @@
 	"admin.gateway.newKey": "새 API 키가 생성되었습니다. 지금 복사하세요",
 	"admin.gateway.noKeys": "API 키가 아직 없습니다",
 	"admin.gateway.title": "API 게이트웨이",
-	"chat.greeting": "무엇을 도와드릴까요?"
+	"chat.greeting": "무엇을 도와드릴까요?",
+
+	"admin.subagents": "서브 에이전트",
+	"admin.subagentsEnabled": "서브 에이전트 활성화",
+	"admin.subagentsHint": "AI가 서브 에이전트에 작업을 위임할 수 있게 합니다. 각 서브 에이전트는 전체 도구 액세스 권한이 있는 실제 채팅을 생성합니다. 추가 LLM 호출을 사용합니다.",
+	"admin.subagentsMaxConcurrent": "최대 동시 실행",
+	"admin.subagentsMaxConcurrentHint": "동시 서브 에이전트",
+	"admin.subagentsMaxIterations": "최대 반복 횟수",
+	"admin.subagentsMaxIterationsHint": "서브 에이전트당 도구 루프",
+	"admin.subagentsMaxOutput": "최대 출력",
+	"admin.subagentsSystemPrompt": "시스템 프롬프트",
+	"admin.subagentsSystemPromptPlaceholder": "당신은 서브 에이전트입니다...",
+	"admin.subagentsSystemPromptHint": "기본값을 사용하려면 비워두세요."
 }
diff --git a/cptr/frontend/src/lib/i18n/locales/pt-BR.json b/cptr/frontend/src/lib/i18n/locales/pt-BR.json
index e63b126..ce689a0 100644
--- a/cptr/frontend/src/lib/i18n/locales/pt-BR.json
+++ b/cptr/frontend/src/lib/i18n/locales/pt-BR.json
@@ -569,5 +569,17 @@
 	"admin.gateway.newKey": "Nova chave API criada. Copie-a agora",
 	"admin.gateway.noKeys": "Nenhuma chave API ainda",
 	"admin.gateway.title": "API Gateway",
-	"chat.greeting": "Como posso ajudar?"
+	"chat.greeting": "Como posso ajudar?",
+
+	"admin.subagents": "Sub-agentes",
+	"admin.subagentsEnabled": "Habilitar sub-agentes",
+	"admin.subagentsHint": "Permite que a IA delegue tarefas para sub-agentes. Cada sub-agente cria um chat real com acesso total às ferramentas. Usa chamadas LLM adicionais.",
+	"admin.subagentsMaxConcurrent": "Máx. simultâneos",
+	"admin.subagentsMaxConcurrentHint": "sub-agentes simultâneos",
+	"admin.subagentsMaxIterations": "Máx. iterações",
+	"admin.subagentsMaxIterationsHint": "loops de ferramentas por sub-agente",
+	"admin.subagentsMaxOutput": "Máx. saída",
+	"admin.subagentsSystemPrompt": "Prompt do sistema",
+	"admin.subagentsSystemPromptPlaceholder": "Você é um sub-agente...",
+	"admin.subagentsSystemPromptHint": "Deixe vazio para o padrão integrado."
 }
diff --git a/cptr/frontend/src/lib/i18n/locales/ru.json b/cptr/frontend/src/lib/i18n/locales/ru.json
index 4f2b661..5a149ea 100644
--- a/cptr/frontend/src/lib/i18n/locales/ru.json
+++ b/cptr/frontend/src/lib/i18n/locales/ru.json
@@ -569,5 +569,17 @@
 	"admin.gateway.newKey": "Новый API-ключ создан. Скопируйте его сейчас",
 	"admin.gateway.noKeys": "API-ключей пока нет",
 	"admin.gateway.title": "API-шлюз",
-	"chat.greeting": "Чем могу помочь?"
+	"chat.greeting": "Чем могу помочь?",
+
+	"admin.subagents": "Суб-агенты",
+	"admin.subagentsEnabled": "Включить суб-агентов",
+	"admin.subagentsHint": "Позволяет ИИ делегировать задачи суб-агентам. Каждый суб-агент создаёт реальный чат с полным доступом к инструментам. Использует дополнительные вызовы LLM.",
+	"admin.subagentsMaxConcurrent": "Макс. одновременно",
+	"admin.subagentsMaxConcurrentHint": "одновременных суб-агентов",
+	"admin.subagentsMaxIterations": "Макс. итераций",
+	"admin.subagentsMaxIterationsHint": "циклов инструментов на суб-агента",
+	"admin.subagentsMaxOutput": "Макс. вывод",
+	"admin.subagentsSystemPrompt": "Системный промпт",
+	"admin.subagentsSystemPromptPlaceholder": "Вы — суб-агент...",
+	"admin.subagentsSystemPromptHint": "Оставьте пустым для значения по умолчанию."
 }
diff --git a/cptr/frontend/src/lib/i18n/locales/zh-CN.json b/cptr/frontend/src/lib/i18n/locales/zh-CN.json
index 33ad63f..4efb68d 100644
--- a/cptr/frontend/src/lib/i18n/locales/zh-CN.json
+++ b/cptr/frontend/src/lib/i18n/locales/zh-CN.json
@@ -569,5 +569,17 @@
 	"admin.gateway.newKey": "新 API 密钥已创建。请立即复制",
 	"admin.gateway.noKeys": "暂无 API 密钥",
 	"admin.gateway.title": "API 网关",
-	"chat.greeting": "有什么可以帮您的？"
+	"chat.greeting": "有什么可以帮您的？",
+
+	"admin.subagents": "子代理",
+	"admin.subagentsEnabled": "启用子代理",
+	"admin.subagentsHint": "允许 AI 将任务委托给子代理。每个子代理会创建一个拥有完整工具访问权限的真实聊天。会使用额外的 LLM 调用。",
+	"admin.subagentsMaxConcurrent": "最大并发数",
+	"admin.subagentsMaxConcurrentHint": "个同时运行的子代理",
+	"admin.subagentsMaxIterations": "最大迭代次数",
+	"admin.subagentsMaxIterationsHint": "每个子代理的工具循环次数",
+	"admin.subagentsMaxOutput": "最大输出",
+	"admin.subagentsSystemPrompt": "系统提示词",
+	"admin.subagentsSystemPromptPlaceholder": "你是一个子代理...",
+	"admin.subagentsSystemPromptHint": "留空以使用内置默认值。"
 }
diff --git a/cptr/frontend/src/lib/i18n/locales/zh-TW.json b/cptr/frontend/src/lib/i18n/locales/zh-TW.json
index 9e4b8ef..6b54bf6 100644
--- a/cptr/frontend/src/lib/i18n/locales/zh-TW.json
+++ b/cptr/frontend/src/lib/i18n/locales/zh-TW.json
@@ -569,5 +569,17 @@
 	"admin.gateway.newKey": "新 API 金鑰已建立。請立即複製",
 	"admin.gateway.noKeys": "尚無 API 金鑰",
 	"admin.gateway.title": "API 閘道",
-	"chat.greeting": "有什麼可以幫您的？"
+	"chat.greeting": "有什麼可以幫您的？",
+
+	"admin.subagents": "子代理",
+	"admin.subagentsEnabled": "啟用子代理",
+	"admin.subagentsHint": "允許 AI 將任務委派給子代理。每個子代理會建立一個擁有完整工具存取權限的真實聊天。會使用額外的 LLM 呼叫。",
+	"admin.subagentsMaxConcurrent": "最大同時數",
+	"admin.subagentsMaxConcurrentHint": "個同時執行的子代理",
+	"admin.subagentsMaxIterations": "最大迭代次數",
+	"admin.subagentsMaxIterationsHint": "每個子代理的工具迴圈次數",
+	"admin.subagentsMaxOutput": "最大輸出",
+	"admin.subagentsSystemPrompt": "系統提示詞",
+	"admin.subagentsSystemPromptPlaceholder": "你是一個子代理...",
+	"admin.subagentsSystemPromptHint": "留空以使用內建預設值。"
 }
diff --git a/cptr/utils/context.py b/cptr/utils/context.py
index 3451f71..c0d8aca 100644
--- a/cptr/utils/context.py
+++ b/cptr/utils/context.py
@@ -63,11 +63,16 @@ def should_compact(
 
 
 def _get_threshold() -> int:
-    """Read threshold: config.toml > env var/default."""
+    """Read threshold: app_config (admin UI) > config.toml [chat] > env var/default."""
     try:
         from cptr.utils.config import load_config
 
         config = load_config()
+        # Admin UI saves to [app_config] with dotted keys
+        val = config.get("app_config", {}).get("chat.compact_token_threshold")
+        if val is not None:
+            return int(val)
+        # Manual config.toml [chat] section
         val = config.get("chat", {}).get("compact_token_threshold")
         if val is not None:
             return int(val)