diff --git a/backend/routes/evals.py b/backend/routes/evals.py
index 798a9d8..5de5c5d 100644
--- a/backend/routes/evals.py
+++ b/backend/routes/evals.py
@@ -16,8 +16,8 @@ class Eval(BaseModel):
 @router.get("/evals")
 async def get_evals():
     # Get all evals from EVALS_DIR
-    input_dir = EVALS_DIR + "/inputs"
-    output_dir = EVALS_DIR + "/outputs"
+    input_dir = f"{EVALS_DIR}/inputs"
+    output_dir = f"{EVALS_DIR}/outputs"
 
     evals: list[Eval] = []
     for file in os.listdir(input_dir):
diff --git a/backend/run_evals.py b/backend/run_evals.py
index a5cfefb..e132839 100644
--- a/backend/run_evals.py
+++ b/backend/run_evals.py
@@ -15,8 +15,8 @@ STACK = "html_tailwind"
 
 
 async def main():
-    INPUT_DIR = EVALS_DIR + "/inputs"
-    OUTPUT_DIR = EVALS_DIR + "/outputs"
+    INPUT_DIR = f"{EVALS_DIR}/inputs"
+    OUTPUT_DIR = f"{EVALS_DIR}/outputs"
 
     # Get all the files in the directory (only grab pngs)
     evals = [f for f in os.listdir(INPUT_DIR) if f.endswith(".png")]