diff --git a/src/resources/devtools/forbidden-signatures.txt b/src/resources/devtools/forbidden-signatures.txt
index 54b285678..7d24dc75e 100644
--- a/src/resources/devtools/forbidden-signatures.txt
+++ b/src/resources/devtools/forbidden-signatures.txt
@@ -109,3 +109,6 @@ java.lang.Object#notifyAll()
 
 @defaultMessage Don't interrupt threads use FutureUtils#cancel(Future<T>) instead
 java.util.concurrent.Future#cancel(boolean)
+
+@defaultMessage Unnecessary, inefficient, and confusing conversion of String.toString
+java.lang.String#toString()