diff --git a/doc/PKGBUILD.5.asciidoc b/doc/PKGBUILD.5.asciidoc
index e8ce691f..285627ab 100644
--- a/doc/PKGBUILD.5.asciidoc
+++ b/doc/PKGBUILD.5.asciidoc
@@ -342,9 +342,12 @@ files into the packaging directory, with optional `prepare()`, `build()`, and
 *prepare() Function*::
 	An optional `prepare()` function can be specified in which operations to
 	prepare the sources for building, such as patching, are performed. This
-	function is run after the source extraction and before the `build()`
-	function. The `prepare()` function is skipped when source extraction
-	is skipped.
+	function is run exactly once, after the source extraction and before the
+	`build()` function. The `prepare()` function is skipped when source
+	extraction is skipped. No system-specific or build-specific commands should
+	be run during `prepare()` under any circumstances, as they are meant to run
+	exclusively during `build()`, and features like `buildflags` or `makeflags`
+	are expressly not available.
 
 *build() Function*::
 	The optional `build()` function is use to compile and/or adjust the source