diff --git a/app/router/private/__init__.py b/app/router/private/__init__.py
index f577a77..27d3eb3 100644
--- a/app/router/private/__init__.py
+++ b/app/router/private/__init__.py
@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from . import avatar  # noqa: F401
+from . import avatar, oauth, username  # noqa: F401
 from .router import router as private_router
 
 __all__ = [
diff --git a/app/router/private/avatar.py b/app/router/private/avatar.py
index 3f2116f..308253c 100644
--- a/app/router/private/avatar.py
+++ b/app/router/private/avatar.py
@@ -16,13 +16,28 @@ from PIL import Image
 from sqlmodel.ext.asyncio.session import AsyncSession
 
 
-@router.post("/avatar/upload", tags=["avatar"])
+@router.post(
+    "/avatar/upload",
+    name="上传头像",
+)
 async def upload_avatar(
-    file: str = Body(...),
-    user_id: int = Body(...),
+    file: str = Body(..., description="Base64 编码的图片数据"),
+    user_id: int = Body(..., description="用户 ID"),
     storage: StorageService = Depends(get_storage_service),
     session: AsyncSession = Depends(get_db),
 ):
+    """上传用户头像
+
+    接收 Base64 编码的图片数据，验证图片格式和大小后存储到头像目录，并更新用户的头像 URL
+
+    限制条件:
+    - 支持的图片格式: PNG、JPEG、GIF
+    - 最大文件大小: 5MB
+    - 最大图片尺寸: 256x256 像素
+
+    返回:
+    - 头像 URL 和文件哈希值
+    """
     content = base64.b64decode(file)
 
     user = await session.get(User, user_id)
diff --git a/app/router/private/oauth.py b/app/router/private/oauth.py
index 858371f..68142fd 100644
--- a/app/router/private/oauth.py
+++ b/app/router/private/oauth.py
@@ -13,12 +13,16 @@ from sqlmodel import select, text
 from sqlmodel.ext.asyncio.session import AsyncSession
 
 
-@router.post("/oauth-app/create", tags=["OAuth"])
+@router.post(
+    "/oauth-app/create",
+    name="创建 OAuth 应用",
+    description="创建一个新的 OAuth 应用程序，并生成客户端 ID 和密钥",
+)
 async def create_oauth_app(
-    name: str = Body(..., max_length=100),
-    description: str = Body(""),
-    redirect_uris: list[str] = Body(...),
-    owner_id: int = Body(...),
+    name: str = Body(..., max_length=100, description="应用程序名称"),
+    description: str = Body("", description="应用程序描述"),
+    redirect_uris: list[str] = Body(..., description="允许的重定向 URI 列表"),
+    owner_id: int = Body(..., description="应用程序所有者的用户 ID"),
     session: AsyncSession = Depends(get_db),
 ):
     result = await session.execute(  # pyright: ignore[reportDeprecated]
@@ -48,8 +52,15 @@ async def create_oauth_app(
     }
 
 
-@router.get("/oauth-apps/{client_id}", tags=["OAuth"])
-async def get_oauth_app(client_id: int, session: AsyncSession = Depends(get_db)):
+@router.get(
+    "/oauth-apps/{client_id}",
+    name="获取 OAuth 应用信息",
+    description="通过客户端 ID 获取 OAuth 应用的详细信息",
+)
+async def get_oauth_app(
+    client_id: int,
+    session: AsyncSession = Depends(get_db),
+):
     oauth_app = await session.get(OAuthClient, client_id)
     if not oauth_app:
         raise HTTPException(status_code=404, detail="OAuth app not found")
@@ -61,8 +72,15 @@ async def get_oauth_app(client_id: int, session: AsyncSession = Depends(get_db))
     }
 
 
-@router.get("/oauth-apps/user/{owner_id}", tags=["OAuth"])
-async def get_user_oauth_apps(owner_id: int, session: AsyncSession = Depends(get_db)):
+@router.get(
+    "/oauth-apps/user/{owner_id}",
+    name="获取用户的 OAuth 应用列表",
+    description="获取指定用户创建的所有 OAuth 应用程序",
+)
+async def get_user_oauth_apps(
+    owner_id: int,
+    session: AsyncSession = Depends(get_db),
+):
     oauth_apps = await session.exec(
         select(OAuthClient).where(OAuthClient.owner_id == owner_id)
     )
@@ -77,7 +95,12 @@ async def get_user_oauth_apps(owner_id: int, session: AsyncSession = Depends(get
     ]
 
 
-@router.delete("/oauth-app/{client_id}", tags=["OAuth"], status_code=204)
+@router.delete(
+    "/oauth-app/{client_id}",
+    status_code=204,
+    name="删除 OAuth 应用",
+    description="删除指定的 OAuth 应用程序及其关联的所有令牌",
+)
 async def delete_oauth_app(
     client_id: int,
     session: AsyncSession = Depends(get_db),
@@ -96,12 +119,16 @@ async def delete_oauth_app(
     await session.commit()
 
 
-@router.patch("/oauth-app/{client_id}", tags=["OAuth"])
+@router.patch(
+    "/oauth-app/{client_id}",
+    name="更新 OAuth 应用",
+    description="更新指定 OAuth 应用的名称、描述和重定向 URI",
+)
 async def update_oauth_app(
     client_id: int,
-    name: str = Body(..., max_length=100),
-    description: str = Body(""),
-    redirect_uris: list[str] = Body(...),
+    name: str = Body(..., max_length=100, description="应用程序新名称"),
+    description: str = Body("", description="应用程序新描述"),
+    redirect_uris: list[str] = Body(..., description="新的重定向 URI 列表"),
     session: AsyncSession = Depends(get_db),
 ):
     oauth_client = await session.get(OAuthClient, client_id)
@@ -122,7 +149,11 @@ async def update_oauth_app(
     }
 
 
-@router.post("/oauth-app/{client_id}/refresh", tags=["OAuth"])
+@router.post(
+    "/oauth-app/{client_id}/refresh",
+    name="刷新 OAuth 密钥",
+    description="为指定的 OAuth 应用生成新的客户端密钥，并使所有现有的令牌失效",
+)
 async def refresh_secret(
     client_id: int,
     session: AsyncSession = Depends(get_db),
@@ -148,12 +179,16 @@ async def refresh_secret(
     }
 
 
-@router.post("/oauth-app/{client_id}/code")
+@router.post(
+    "/oauth-app/{client_id}/code",
+    name="生成 OAuth 授权码",
+    description="为特定用户和 OAuth 应用生成授权码，用于授权码授权流程",
+)
 async def generate_oauth_code(
     client_id: int,
-    user_id: int = Body(...),
-    redirect_uri: str = Body(...),
-    scopes: list[str] = Body(...),
+    user_id: int = Body(..., description="授权用户的 ID"),
+    redirect_uri: str = Body(..., description="授权后重定向的 URI"),
+    scopes: list[str] = Body(..., description="请求的权限范围列表"),
     session: AsyncSession = Depends(get_db),
     redis: Redis = Depends(get_redis),
 ):
@@ -172,3 +207,9 @@ async def generate_oauth_code(
         mapping={"user_id": user_id, "scopes": ",".join(scopes)},
     )
     await redis.expire(f"oauth:code:{client_id}:{code}", 300)
+
+    return {
+        "code": code,
+        "redirect_uri": redirect_uri,
+        "expires_in": 300,
+    }
diff --git a/app/router/private/router.py b/app/router/private/router.py
index 1d3a6e4..da6944b 100644
--- a/app/router/private/router.py
+++ b/app/router/private/router.py
@@ -35,5 +35,6 @@ async def verify_signature(
 router = APIRouter(
     prefix="/api/private",
     dependencies=[Depends(verify_signature)],
-    include_in_schema=False,
+    include_in_schema=settings.debug,
+    tags=["私有 API"],
 )
diff --git a/app/router/private/username.py b/app/router/private/username.py
index 27da481..8140e3b 100644
--- a/app/router/private/username.py
+++ b/app/router/private/username.py
@@ -10,13 +10,27 @@ from sqlmodel import select
 from sqlmodel.ext.asyncio.session import AsyncSession
 
 
-@router.post("/rename", tags=["rename"])
+@router.post(
+    "/rename",
+    name="修改用户名",
+)
 async def user_rename(
-    user_id: int = Body(...),
-    new_name: str = Body(...),
+    user_id: int = Body(..., description="要修改名称的用户 ID"),
+    new_name: str = Body(..., description="新的用户名"),
     session: AsyncSession = Depends(get_db),
     # currentUser: User = Depends(get_current_user)
 ):
+    """修改用户名
+
+    为指定用户修改用户名，并将原用户名添加到历史用户名列表中
+
+    错误情况:
+    - 404: 找不到指定用户
+    - 409: 新用户名已被占用
+
+    返回:
+    - 成功: None
+    """
     current_user = (await session.exec(select(User).where(User.id == user_id))).first()
     if current_user is None:
         raise HTTPException(404, "User not found")
diff --git a/main.py b/main.py
index d9a9192..d279318 100644
--- a/main.py
+++ b/main.py
@@ -39,11 +39,18 @@ async def lifespan(app: FastAPI):
     await redis_client.aclose()
 
 
+desc = (
+    "osu! API 模拟服务器，支持 osu! API v2 和 osu!lazer 的绝大部分功能。\n\n"
+    "官方文档：[osu!web 文档](https://osu.ppy.sh/docs/index.html)"
+)
+if settings.debug:
+    desc += "\n\n私有 API 签名机制：[GitHub](https://github.com/GooGuTeam/osu_lazer_api/wiki/%E7%A7%81%E6%9C%89-API-%E7%AD%BE%E5%90%8D%E9%AA%8C%E8%AF%81%E6%9C%BA%E5%88%B6)"
+
 app = FastAPI(
     title="osu! API 模拟服务器",
     version="1.0.0",
     lifespan=lifespan,
-    summary="osu! API 模拟服务器，支持 osu! API v2 和 osu!lazer 的绝大部分功能。官方文档：https://osu.ppy.sh/docs/index.html",
+    description=desc,
 )
 
 app.include_router(api_v2_router)