diff --git a/.gitignore b/.gitignore
index eae0de7df..e1caf184f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,3 +29,4 @@ gen_jwks.json
 gen_private.json
 .pytest_cache
 .ruff_cache
+postgrest-module-graph.png
diff --git a/nix/tools/devTools.nix b/nix/tools/devTools.nix
index 252bc223d..61a3e6252 100644
--- a/nix/tools/devTools.nix
+++ b/nix/tools/devTools.nix
@@ -129,7 +129,7 @@ let
       {
         name = "postgrest-hsie-graph-modules";
         docs = "Create a PNG graph of modules imported within the codebase.";
-        args = [ "ARG_POSITIONAL_SINGLE([outfile], [Output filename])" ];
+        args = [ "ARG_OPTIONAL_SINGLE([outfile], [o], [Output filename], [postgrest-module-graph.png])" ];
       }
       ''
         ${hsie} graph-modules main src | ${graphviz}/bin/dot -Tpng -o "$_arg_outfile"