diff --git a/tests/test-sources/plugins/by-name/efmls-configs/default.nix b/tests/test-sources/plugins/by-name/efmls-configs/default.nix
index 39494981..52cc5175 100644
--- a/tests/test-sources/plugins/by-name/efmls-configs/default.nix
+++ b/tests/test-sources/plugins/by-name/efmls-configs/default.nix
@@ -22,6 +22,10 @@
       ];
 
       brokenTools = [
+        # TODO: 2026-01-23: dmd build failure with gcc 15 (nullptr identifier)
+        "dfmt"
+        "dmd"
+
         # 2025-12-24: phpPackages.php-codesniffer is broken
         # https://github.com/NixOS/nixpkgs/pull/459254#issuecomment-3689578764
         "phpcbf"