diff --git a/src/kleinanzeigen_bot/__init__.py b/src/kleinanzeigen_bot/__init__.py
index ee325c0..0a0653e 100644
--- a/src/kleinanzeigen_bot/__init__.py
+++ b/src/kleinanzeigen_bot/__init__.py
@@ -358,7 +358,8 @@ class KleinanzeigenBot(WebScrapingMixin):
 
             ad_cfg["description"] = description_config["prefix"] + (ad_cfg["description"] or "") + description_config["suffix"]
             ad_cfg["description"] = ad_cfg["description"].replace("@", "(at)")
-            ensure(len(ad_cfg["description"]) <= 4000, f"Length of ad description including prefix and suffix exceeds 4000 chars. @ [{ad_file}]")
+            ensure(len(ad_cfg["description"]) <= 4000, f"""Length of ad description including prefix and suffix exceeds 4000 chars. Description length: {
+                   len(ad_cfg['description'])} chars. @ {ad_file}""")
 
             # pylint: disable=cell-var-from-loop
             def assert_one_of(path:str, allowed:Iterable[str]) -> None: