diff --git a/internal/multiplex/session_fuzz.go b/internal/multiplex/session_fuzz.go
index 578cf51..2d083b0 100644
--- a/internal/multiplex/session_fuzz.go
+++ b/internal/multiplex/session_fuzz.go
@@ -1,3 +1,5 @@
+// +build gofuzz
+
 package multiplex
 
 func setupSesh_fuzz(unordered bool) *Session {
diff --git a/internal/server/first_packet_fuzz.go b/internal/server/first_packet_fuzz.go
index c813771..2003508 100644
--- a/internal/server/first_packet_fuzz.go
+++ b/internal/server/first_packet_fuzz.go
@@ -1,3 +1,5 @@
+// +build gofuzz
+
 package server
 
 import (