diff --git a/scalafix-cli/src/main/scala/scalafix/internal/v1/Args.scala b/scalafix-cli/src/main/scala/scalafix/internal/v1/Args.scala
index fb53b23e4..8d21ddb1c 100644
--- a/scalafix-cli/src/main/scala/scalafix/internal/v1/Args.scala
+++ b/scalafix-cli/src/main/scala/scalafix/internal/v1/Args.scala
@@ -149,7 +149,7 @@ case class Args(
     )
     exclude: List[PathMatcher] = Nil,
     @Description(
-      "Additional classpath for compiling and classloading custom rules."
+      "Additional classpath for compiling and classloading custom rules, as a set of filesystem paths, separated by ':' on Unix or ';' on Windows."
     )
     toolClasspath: URLClassLoader = ClasspathOps.thisClassLoader,
     @Description("The encoding to use for reading/writing files")