diff --git a/build.py b/build.py
index 05fdf2f..aa2060c 100644
--- a/build.py
+++ b/build.py
@@ -274,6 +274,10 @@ def main() -> None:
     output.write_text(html_content, encoding="utf-8")
     print(f"Built {output}")
 
+    robots = PUBLIC_DIR / "robots.txt"
+    robots.write_text("User-agent: *\nDisallow: /\n", encoding="utf-8")
+    print(f"Built {robots}")
+
     print(f"Zips in {ZIPS_DIR}:")
     for z in sorted(ZIPS_DIR.iterdir()):
         print(f"  {z.name}")