diff --git a/yarn-project/noir-protocol-circuits-types/src/scripts/generate_declaration_files.ts b/yarn-project/noir-protocol-circuits-types/src/scripts/generate_declaration_files.ts
index 98a5f2f06b4..2a02f805d3f 100644
--- a/yarn-project/noir-protocol-circuits-types/src/scripts/generate_declaration_files.ts
+++ b/yarn-project/noir-protocol-circuits-types/src/scripts/generate_declaration_files.ts
@@ -12,6 +12,10 @@ export = circuit;
 const target = fileURLToPath(new URL('../../artifacts', import.meta.url).href);
 const files = await readdir(target);
 for (const file of files) {
+  // guard against running this script twice without cleaning the artifacts/ dir first
+  if (!file.endsWith('.json')) {
+    continue;
+  }
   const name = file.replace('.json', '');
   await writeFile(join(target, `${name}.d.json.ts`), content);
 }