diff --git a/src/toOpenAIMessages.ts b/src/toOpenAIMessages.ts
index e148363..7d61456 100644
--- a/src/toOpenAIMessages.ts
+++ b/src/toOpenAIMessages.ts
@@ -40,12 +40,12 @@ function formatName(name: string): string {
   return FoldToAscii.foldReplacing(name)
     // White spaces are not allowed
     .replace(" ", "_")
+    // replace characters that are not accepted by api with '_'
+    .replace(/[^a-zA-Z0-9_-]/g, "_")
     // remove trailing '-_' characters
     .replace(/^[-_]+|[-_]+$/g, "")
     // remove duplicated '-_' characters
-    .replace(/([-_])*/g, "")
-    // replace characters that are not accepted by api with '?'
-    .replace(/[^a-zA-Z0-9_-]/g, "?");
+    .replace(/([-_])*/g, "$1");
 }
 
 /**