diff --git a/pkgs/development/tools/misc/otool/default.nix b/pkgs/development/tools/misc/otool/default.nix
index aa365fc29d59..21eb2b591c22 100644
--- a/pkgs/development/tools/misc/otool/default.nix
+++ b/pkgs/development/tools/misc/otool/default.nix
@@ -1,5 +1,8 @@
 { stdenv }:
 
+# this tool only exists on darwin
+assert stdenv.isDarwin;
+
 stdenv.mkDerivation {
   name = "otool";
 
diff --git a/pkgs/development/tools/misc/setFile/default.nix b/pkgs/development/tools/misc/setFile/default.nix
index 9f86184634f1..e3fbd2cbc6da 100644
--- a/pkgs/development/tools/misc/setFile/default.nix
+++ b/pkgs/development/tools/misc/setFile/default.nix
@@ -1,5 +1,8 @@
 { stdenv }:
 
+# this tool only exists on darwin
+assert stdenv.isDarwin;
+
 stdenv.mkDerivation {
   name = "setFile";