diff --git a/doc/build-helpers/trivial-build-helpers.chapter.md b/doc/build-helpers/trivial-build-helpers.chapter.md
index 31b42bd77426..ff00548e049a 100644
--- a/doc/build-helpers/trivial-build-helpers.chapter.md
+++ b/doc/build-helpers/trivial-build-helpers.chapter.md
@@ -501,7 +501,7 @@ writeTextFile {
   text = ''
     Contents of File
   '';
-  destination = "share/my-file";
+  destination = "/share/my-file";
 }
 ```
 
@@ -586,7 +586,7 @@ writeTextFile {
     echo "hi"
   '';
   executable = true;
-  destination = "bin/my-script";
+  destination = "/bin/my-script";
 }
 ```
 
@@ -674,7 +674,7 @@ writeTextFile {
     echo "hi"
   '';
   executable = true;
-  destination = "bin/my-script";
+  destination = "/bin/my-script";
 }
 ```
 
diff --git a/pkgs/build-support/trivial-builders/default.nix b/pkgs/build-support/trivial-builders/default.nix
index 3bccc871a7dc..a02fe1fd6d0a 100644
--- a/pkgs/build-support/trivial-builders/default.nix
+++ b/pkgs/build-support/trivial-builders/default.nix
@@ -86,6 +86,13 @@ rec {
     , preferLocalBuild ? true
     , derivationArgs ? { }
     }:
+    assert lib.assertMsg (destination != "" -> (lib.hasPrefix "/" destination && destination != "/")) ''
+      destination must be an absolute path, relative to the derivation's out path,
+      got '${destination}' instead.
+
+      Ensure that the path starts with a / and specifies at least the filename.
+    '';
+
     let
       matches = builtins.match "/bin/([^/]+)" destination;
     in