diff --git a/src/api/checkpoint_routes.py b/src/api/checkpoint_routes.py
index 4280baa..807587b 100644
--- a/src/api/checkpoint_routes.py
+++ b/src/api/checkpoint_routes.py
@@ -10,7 +10,7 @@ from pydantic import BaseModel
 from typing import Optional
 
 from src.blackboard.operations import Blackboard
-from src.blackboard.registry import ProjectRegistry
+from src.utils import get_data_root
 
 router = APIRouter(prefix="/api/projects/{project_id}/tasks/{task_id}/checkpoints", tags=["checkpoints"])
 
@@ -33,9 +33,8 @@ class ResolveCheckpointRequest(BaseModel):
 # ── 工具 ──
 
 def _bb(project_id: str) -> Blackboard:
-    registry = ProjectRegistry()
-    db_path = registry.get_db_path(project_id)
-    if not db_path:
+    db_path = get_data_root() / project_id / "blackboard.db"
+    if not db_path.exists():
         raise HTTPException(status_code=404, detail="Project not found")
     return Blackboard(db_path)