diff --git a/main.cpp b/main.cpp
index 43f3597..049a9f5 100644
--- a/main.cpp
+++ b/main.cpp
@@ -150,7 +150,7 @@ static int AL(Cfg &cfg, Messages &msgs, Usage &out, volatile int *interrupted, s
       if (err) *err = std::move(lerr);
       rc = -1; break;
     }
-    out.prompt_tokens += u.prompt_tokens;
+    out.prompt_tokens = u.prompt_tokens;
     out.completion_tokens += u.completion_tokens;
     out.total_tokens += u.total_tokens;
     out.context_tokens = u.context_tokens;