diff --git a/app/components/agent/AgentToolbar.vue b/app/components/agent/AgentToolbar.vue
index a308477..2374b8a 100644
--- a/app/components/agent/AgentToolbar.vue
+++ b/app/components/agent/AgentToolbar.vue
@@ -50,8 +50,8 @@ const emit = defineEmits<{
       </div>
 
       <!-- System prompt button -->
-      <button class="icon-btn" title="系统提示词" @click="emit('showPrompt')">
-        <Icon name="lucide:info" />
+      <button class="icon-btn" title="系统提示词设置" @click="emit('showPrompt')">
+        <Icon name="lucide:settings-2" />
       </button>
     </div>
   </div>
diff --git a/app/pages/chat/[agentSlug]/index.vue b/app/pages/chat/[agentSlug]/index.vue
index 2da18a9..d5e7903 100644
--- a/app/pages/chat/[agentSlug]/index.vue
+++ b/app/pages/chat/[agentSlug]/index.vue
@@ -19,7 +19,13 @@ const isMobile = useMediaQuery('(max-width: 767.98px)');
 const sidebarCollapsed = ref(false);
 const mobileSidebarOpen = ref(false);
 const showPromptModal = ref(false);
-const systemPromptText = ref("");
+const agentSystemPrompt = ref("");
+const systemPromptText = computed(() =>
+  sessions.currentSession.value?.systemPrompt?.trim() || agentSystemPrompt.value || "",
+);
+const isCustomPrompt = computed(() =>
+  !!(sessions.currentSession.value?.systemPrompt?.trim()),
+);
 const preferredModelId = ref<number | null>(null);
 const guestDefaultModelId = ref<number | null>(null);
 
@@ -146,12 +152,20 @@ async function loadSystemPrompt() {
     const res = await $fetch<{ code: number; data: { systemPrompt?: string } }>(
       `/api/agents/${agentSlug.value}/info`,
     );
-    systemPromptText.value = res.data?.systemPrompt ?? "";
+    agentSystemPrompt.value = res.data?.systemPrompt ?? "";
   } catch {
-    systemPromptText.value = "";
+    agentSystemPrompt.value = "";
   }
 }
 
+async function handleSavePrompt(prompt: string | null) {
+  if (!sessions.currentSessionId.value) return;
+  await sessions.updateSessionConfig(sessions.currentSessionId.value, { systemPrompt: prompt });
+  const { $toast } = useNuxtApp();
+  $toast?.success?.("系统提示词已更新");
+  showPromptModal.value = false;
+}
+
 watch(
   () => sessions.currentSessionId.value,
   async (sid) => {
@@ -293,6 +307,8 @@ onMounted(async () => {
   <AgentSystemPromptModal
     :show="showPromptModal"
     :system-prompt="systemPromptText"
+    :is-custom="isCustomPrompt"
     @close="showPromptModal = false"
+    @save="handleSavePrompt"
   />
 </template>