diff --git a/app/dependencies.py b/app/dependencies.py
index c433848..44860e1 100644
--- a/app/dependencies.py
+++ b/app/dependencies.py
@@ -64,10 +64,15 @@ async def get_current_user(request: Request) -> Optional[UserContext]:
     # Try header first (API clients)
     ctx = get_user_from_header(request)
     if ctx:
+        # Add l2_server from settings
+        ctx.l2_server = settings.l2_server
         return ctx
 
     # Fall back to cookie (browser)
-    return get_user_from_cookie(request)
+    ctx = get_user_from_cookie(request)
+    if ctx:
+        ctx.l2_server = settings.l2_server
+    return ctx
 
 
 async def require_auth(request: Request) -> UserContext:
diff --git a/app/routers/api.py b/app/routers/api.py
index fe4f644..10421e5 100644
--- a/app/routers/api.py
+++ b/app/routers/api.py
@@ -15,8 +15,8 @@ import yaml
 from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel
 
+from artdag_common.middleware.auth import UserContext
 from ..dependencies import require_auth, get_redis_client, get_cache_manager
-from ..services.auth_service import UserContext
 
 router = APIRouter()
 logger = logging.getLogger(__name__)
diff --git a/app/routers/cache.py b/app/routers/cache.py
index ec0f1b0..9120450 100644
--- a/app/routers/cache.py
+++ b/app/routers/cache.py
@@ -14,12 +14,13 @@ from pydantic import BaseModel
 
 from artdag_common import render
 from artdag_common.middleware import wants_html, wants_json
+from artdag_common.middleware.auth import UserContext
 
 from ..dependencies import (
     require_auth, get_templates, get_redis_client,
     get_cache_manager, get_current_user
 )
-from ..services.auth_service import UserContext, AuthService
+from ..services.auth_service import AuthService
 from ..services.cache_service import CacheService
 
 router = APIRouter()
diff --git a/app/routers/recipes.py b/app/routers/recipes.py
index 3b66e0c..7199c47 100644
--- a/app/routers/recipes.py
+++ b/app/routers/recipes.py
@@ -13,9 +13,10 @@ from pydantic import BaseModel
 
 from artdag_common import render
 from artdag_common.middleware import wants_html, wants_json
+from artdag_common.middleware.auth import UserContext
 
 from ..dependencies import require_auth, get_templates, get_redis_client, get_cache_manager
-from ..services.auth_service import UserContext, AuthService
+from ..services.auth_service import AuthService
 from ..services.recipe_service import RecipeService
 
 router = APIRouter()
diff --git a/app/routers/runs.py b/app/routers/runs.py
index 652f5a3..e744be5 100644
--- a/app/routers/runs.py
+++ b/app/routers/runs.py
@@ -16,12 +16,12 @@ from pydantic import BaseModel
 
 from artdag_common import render
 from artdag_common.middleware import wants_html, wants_json
+from artdag_common.middleware.auth import UserContext
 
 from ..dependencies import (
     require_auth, get_templates, get_current_user,
     get_redis_client, get_cache_manager
 )
-from ..services.auth_service import UserContext
 from ..services.run_service import RunService
 
 router = APIRouter()
diff --git a/app/routers/storage.py b/app/routers/storage.py
index 0ffc4fa..041e6bd 100644
--- a/app/routers/storage.py
+++ b/app/routers/storage.py
@@ -12,9 +12,9 @@ from pydantic import BaseModel
 
 from artdag_common import render
 from artdag_common.middleware import wants_html, wants_json
+from artdag_common.middleware.auth import UserContext
 
 from ..dependencies import get_database, get_current_user, require_auth, get_templates
-from ..services.auth_service import UserContext
 from ..services.storage_service import StorageService, STORAGE_PROVIDERS_INFO, VALID_PROVIDER_TYPES
 
 router = APIRouter()
diff --git a/app/services/auth_service.py b/app/services/auth_service.py
index 710f8c8..08e67fc 100644
--- a/app/services/auth_service.py
+++ b/app/services/auth_service.py
@@ -6,10 +6,10 @@ import hashlib
 import base64
 import json
 from typing import Optional
-from dataclasses import dataclass
 
 import httpx
 
+from artdag_common.middleware.auth import UserContext
 from ..config import settings
 
 
@@ -21,15 +21,6 @@ REVOKED_KEY_PREFIX = "artdag:revoked:"
 USER_TOKENS_PREFIX = "artdag:user_tokens:"
 
 
-@dataclass
-class UserContext:
-    """User context from token."""
-    username: str
-    actor_id: str
-    token: Optional[str] = None
-    l2_server: Optional[str] = None
-
-
 class AuthService:
     """Service for authentication and token management."""
 
diff --git a/requirements.txt b/requirements.txt
index e308a21..5c57d2c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,4 +11,4 @@ markdown>=3.5.0
 # Core artdag from GitHub
 git+https://github.com/gilesbradshaw/art-dag.git
 # Shared components
-git+https://git.rose-ash.com/art-dag/common.git@932abb8
+git+https://git.rose-ash.com/art-dag/common.git@11aa056