diff --git a/backend/package/yuxi/repositories/agent_repository.py b/backend/package/yuxi/repositories/agent_repository.py
index d32f7849..50dcc831 100644
--- a/backend/package/yuxi/repositories/agent_repository.py
+++ b/backend/package/yuxi/repositories/agent_repository.py
@@ -14,6 +14,7 @@ from yuxi.utils.datetime_utils import utc_now_naive
 DEFAULT_AGENT_SLUG = "default-chatbot"
 DEFAULT_AGENT_NAME = "智能助手"
 DEFAULT_AGENT_BACKEND_ID = "ChatbotAgent"
+DEFAULT_AGENT_DESCRIPTION = "基础的对话机器人，可以回答问题，可在配置中启用需要的工具。"
 DEFAULT_SHARE_CONFIG = {"access_level": "global", "department_ids": [], "user_uids": []}
 ACCESS_LEVELS = {"global", "department", "user"}
 ADMIN_ROLES = {"admin", "superadmin"}
@@ -115,6 +116,9 @@ class AgentRepository:
             if agent.share_config != DEFAULT_SHARE_CONFIG:
                 agent.share_config = DEFAULT_SHARE_CONFIG.copy()
                 needs_update = True
+            if not agent.description:
+                agent.description = DEFAULT_AGENT_DESCRIPTION
+                needs_update = True
             if not agent.is_default:
                 return await self.set_default(agent=agent, updated_by=created_by)
             if needs_update:
@@ -128,7 +132,7 @@ class AgentRepository:
             slug=DEFAULT_AGENT_SLUG,
             backend_id=DEFAULT_AGENT_BACKEND_ID,
             name=DEFAULT_AGENT_NAME,
-            description=None,
+            description=DEFAULT_AGENT_DESCRIPTION,
             icon=None,
             pics=[],
             config_json={"context": {}},
diff --git a/backend/test/unit/repositories/test_agent_repository.py b/backend/test/unit/repositories/test_agent_repository.py
new file mode 100644
index 00000000..8fe4ffff
--- /dev/null
+++ b/backend/test/unit/repositories/test_agent_repository.py
@@ -0,0 +1,62 @@
+from __future__ import annotations
+
+from types import SimpleNamespace
+from unittest.mock import AsyncMock
+
+import pytest
+
+from yuxi.repositories.agent_repository import AgentRepository, DEFAULT_AGENT_DESCRIPTION, DEFAULT_SHARE_CONFIG
+
+
+class FakeDb:
+    def __init__(self):
+        self.added = None
+        self.commit = AsyncMock()
+        self.refresh = AsyncMock()
+
+    def add(self, item):
+        self.added = item
+
+
+@pytest.mark.asyncio
+async def test_ensure_default_agent_creates_description(monkeypatch):
+    db = FakeDb()
+    repo = AgentRepository(db)
+
+    async def get_by_slug(_slug):
+        return None
+
+    monkeypatch.setattr(repo, "get_by_slug", get_by_slug)
+
+    agent = await repo.ensure_default_agent()
+
+    assert agent.description == DEFAULT_AGENT_DESCRIPTION
+    assert db.added is agent
+    db.commit.assert_awaited_once()
+    db.refresh.assert_awaited_once_with(agent)
+
+
+@pytest.mark.asyncio
+async def test_ensure_default_agent_backfills_missing_description(monkeypatch):
+    db = FakeDb()
+    repo = AgentRepository(db)
+    agent = SimpleNamespace(
+        share_config=DEFAULT_SHARE_CONFIG.copy(),
+        is_default=True,
+        description=None,
+        updated_by=None,
+        updated_at=None,
+    )
+
+    async def get_by_slug(_slug):
+        return agent
+
+    monkeypatch.setattr(repo, "get_by_slug", get_by_slug)
+
+    result = await repo.ensure_default_agent(created_by="admin")
+
+    assert result is agent
+    assert agent.description == DEFAULT_AGENT_DESCRIPTION
+    assert agent.updated_by == "admin"
+    db.commit.assert_awaited_once()
+    db.refresh.assert_awaited_once_with(agent)