diff --git a/docs/book.toml b/docs/book.toml
index 912960bc..867dff13 100644
--- a/docs/book.toml
+++ b/docs/book.toml
@@ -13,6 +13,7 @@ command = "mdbook-admonish"
 assets_version = "3.0.3" # do not edit: managed by `mdbook-admonish install`
 
 [preprocessor.yapp]
+command = "mdbook-yapp"
 
 [output.html]
 additional-css = ["./mdbook-admonish.css"]