diff --git a/flake/dev/fmt.nix b/flake/dev/fmt.nix
index 42ab126c..ef609f68 100644
--- a/flake/dev/fmt.nix
+++ b/flake/dev/fmt.nix
@@ -18,6 +18,9 @@
           nixf-diagnose = {
             enable = true;
             priority = -1;
+            ignore = [
+              "sema-unused-def-lambda-witharg-formal"
+            ];
           };
           nixfmt = {
             enable = true;
@@ -63,10 +66,6 @@
             "docs/gfm-alerts-to-admonitions/tests/**/*.yml"
           ];
           formatter.ruff-format.options = [ "--isolated" ];
-          formatter.nixf-diagnose.options = [
-            "--auto-fix"
-            "--ignore=sema-unused-def-lambda-witharg-formal"
-          ];
           formatter.nixf-diagnose.excludes = [
             # sema-unused-def-lambda-noarg-formal
             "ci/rust-analyzer/default.nix"