diff --git a/nix/packages/by-name/ruler/package.nix b/nix/packages/by-name/ruler/package.nix
index ca648f29..8b7b131a 100644
--- a/nix/packages/by-name/ruler/package.nix
+++ b/nix/packages/by-name/ruler/package.nix
@@ -2,8 +2,9 @@
   haskellPackages,
   haskell,
   fetchFromGitea,
+  installShellFiles,
 }: let
-  inherit (haskell.lib.compose) justStaticExecutables;
+  inherit (haskell.lib.compose) justStaticExecutables overrideCabal;
 
   drv =
     haskellPackages.callCabal2nix "ruler"
@@ -15,5 +16,18 @@
       hash = "sha256-gWW5rcL3NI0BExEVqXL+avk7z1/4WYEwEwjtZjqSXNM=";
     })
     {};
+
+  cabalOverrides = o: {
+    buildTools = o.buildTools or [] ++ [installShellFiles];
+    postInstall =
+      o.postInstall or ""
+      + ''
+        installShellCompletion --cmd ruler \
+            --bash <("$out/bin/ruler" --bash-completion-script "$out/bin/ruler") \
+            --fish <("$out/bin/ruler" --fish-completion-script "$out/bin/ruler") \
+            --zsh  <("$out/bin/ruler" --zsh-completion-script "$out/bin/ruler")
+      '';
+  };
 in
-  justStaticExecutables drv
+  justStaticExecutables
+  (overrideCabal cabalOverrides drv)