diff --git a/migrations/0005_chapter_body_md_tts.sql b/migrations/0005_chapter_body_md_tts.sql
index c0c608d..9165833 100644
--- a/migrations/0005_chapter_body_md_tts.sql
+++ b/migrations/0005_chapter_body_md_tts.sql
@@ -9,4 +9,4 @@
 -- text export. The TTS version is production output, regeneratable
 -- whenever the author's beat-placement taste shifts.
 ALTER TABLE chapters
-    ADD COLUMN body_md_tts text;
+    ADD COLUMN IF NOT EXISTS body_md_tts text;