diff --git a/app/components/agent/AgentSystemPromptModal.vue b/app/components/agent/AgentSystemPromptModal.vue
index 58dd6c1..f27f465 100644
--- a/app/components/agent/AgentSystemPromptModal.vue
+++ b/app/components/agent/AgentSystemPromptModal.vue
@@ -2,11 +2,40 @@
 const props = defineProps<{
   show: boolean;
   systemPrompt: string;
+  isCustom: boolean;
 }>();
 
 const emit = defineEmits<{
   close: [];
+  save: [systemPrompt: string | null];
 }>();
+
+const editingText = ref("");
+const saving = ref(false);
+
+watch(
+  () => props.show,
+  (val) => {
+    if (val) {
+      editingText.value = props.systemPrompt;
+    }
+  },
+);
+
+async function handleSave() {
+  saving.value = true;
+  try {
+    const trimmed = editingText.value.trim();
+    emit("save", trimmed.length > 0 ? trimmed.slice(0, 5000) : null);
+  } finally {
+    saving.value = false;
+  }
+}
+
+function handleReset() {
+  editingText.value = "";
+  emit("save", null);
+}
 </script>
 
 <template>
@@ -20,7 +49,29 @@ const emit = defineEmits<{
           </button>
         </div>
         <div class="modal-body">
-          <pre class="prompt-content">{{ systemPrompt || "（未设置系统提示词）" }}</pre>
+          <div v-if="isCustom" class="custom-badge">
+            <Icon name="lucide:check-circle" />
+            <span>当前使用会话自定义提示词</span>
+          </div>
+          <div v-else class="default-badge">
+            <Icon name="lucide:info" />
+            <span>当前使用 Agent 默认提示词，编辑后将覆盖默认值</span>
+          </div>
+          <textarea
+            v-model="editingText"
+            class="prompt-textarea"
+            placeholder="输入系统提示词，留空则使用 Agent 默认"
+            maxlength="5000"
+          />
+          <div class="char-count">{{ editingText.length }} / 5000</div>
+        </div>
+        <div class="modal-footer">
+          <button class="btn-reset" :disabled="saving" @click="handleReset">
+            重置为默认
+          </button>
+          <button class="btn-save" :disabled="saving" @click="handleSave">
+            {{ saving ? "保存中..." : "保存" }}
+          </button>
         </div>
       </div>
     </div>
@@ -90,15 +141,98 @@ const emit = defineEmits<{
   padding: 20px;
   overflow-y: auto;
   flex: 1;
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
 }
 
-.prompt-content {
+.custom-badge,
+.default-badge {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  padding: 8px 12px;
+  border-radius: 8px;
+  font-size: 13px;
+}
+
+.custom-badge {
+  background: var(--color-surface-soft);
+  color: var(--color-primary);
+}
+
+.default-badge {
+  background: var(--color-surface-soft);
+  color: var(--color-muted);
+}
+
+.prompt-textarea {
+  width: 100%;
+  min-height: 200px;
+  padding: 12px;
   font-family: "SF Mono", "Fira Code", monospace;
   font-size: 13px;
   line-height: 1.6;
   color: var(--color-body);
-  white-space: pre-wrap;
-  word-break: break-word;
-  margin: 0;
+  background: var(--color-canvas);
+  border: 1px solid var(--color-hairline);
+  border-radius: 8px;
+  resize: vertical;
+  outline: none;
+  transition: border-color 0.15s;
+}
+
+.prompt-textarea:focus {
+  border-color: var(--color-primary);
+}
+
+.char-count {
+  text-align: right;
+  font-size: 12px;
+  color: var(--color-muted);
+}
+
+.modal-footer {
+  display: flex;
+  justify-content: flex-end;
+  gap: 8px;
+  padding: 12px 20px;
+  border-top: 1px solid var(--color-hairline);
+}
+
+.btn-reset,
+.btn-save {
+  padding: 8px 16px;
+  border-radius: 8px;
+  font-size: 14px;
+  cursor: pointer;
+  transition: all 0.15s;
+  border: 1px solid var(--color-hairline);
+}
+
+.btn-reset {
+  background: var(--color-surface-soft);
+  color: var(--color-muted);
+}
+
+.btn-reset:hover {
+  border-color: var(--color-primary);
+  color: var(--color-ink);
+}
+
+.btn-save {
+  background: var(--color-primary);
+  border-color: var(--color-primary);
+  color: var(--color-on-primary);
+}
+
+.btn-save:hover {
+  opacity: 0.9;
+}
+
+.btn-reset:disabled,
+.btn-save:disabled {
+  opacity: 0.5;
+  cursor: not-allowed;
 }
 </style>