diff --git a/src/infra/task/summarize.ts b/src/infra/task/summarize.ts
index 185bd13..ce69c11 100644
--- a/src/infra/task/summarize.ts
+++ b/src/infra/task/summarize.ts
@@ -34,7 +34,8 @@ function sanitizeSlug(input: string, maxLength = 30): string {
  * Convert Japanese text to romaji slug.
  */
 function toRomajiSlug(text: string): string {
-  const romaji = wanakana.toRomaji(text, { customRomajiMapping: {} });
+  const truncated = text.slice(0, 100);
+  const romaji = wanakana.toRomaji(truncated, { customRomajiMapping: {} });
   return sanitizeSlug(romaji);
 }