diff --git a/js/songs.js b/js/songs.js
index 62114c1..3fd630d 100644
--- a/js/songs.js
+++ b/js/songs.js
@@ -360,9 +360,11 @@ function validateSong(s) {
     prog: String(s.prog || 'I-IV-V').trim().slice(0, 40),
     energy: Math.min(5, Math.max(1, parseInt(s.energy) || 3)),
     effort: Math.min(5, Math.max(1, parseInt(s.effort) || 2)),
-    instr: Array.isArray(s.instr) && s.instr.length 
-      ? s.instr.filter(i => ['eg','ag','b','dr','k','sx','tp','tb','vo','bv','pc'].includes(i))
-      : ['g'],
+    instr: (() => {
+      if (!Array.isArray(s.instr)) return ['g'];
+      const filtered = s.instr.filter(i => ['eg','ag','b','dr','k','sx','tp','tb','vo','bv','pc'].includes(i));
+      return filtered.length > 0 ? filtered : ['g'];
+    })(),
     note: String(s.note || '').trim()
   };
 }
diff --git a/tests/run-tests.js b/tests/run-tests.js
index 8e43fe4..4f971d4 100644
--- a/tests/run-tests.js
+++ b/tests/run-tests.js
@@ -318,8 +318,8 @@ runTest('Defaults to ["g"] if no valid instruments provided', () => {
   // If instr: ['invalid'], filter returns [], but .length check was on ORIGINAL s.instr.
   // Wait: s.instr.length is 1. filter returns []. So it returns [].
   // This looks like a bug in validateSong implementation if it wants to ensure at least one valid instrument.
-  // But I must test the CURRENT code.
-  assertArrayEqual(validateSong({instr: ['invalid']}).instr, []);
+  // Fix: Check filtered array length instead.
+  assertArrayEqual(validateSong({instr: ['invalid']}).instr, ['g']);
   // If instr: 'not-an-array', Array.isArray is false, returns ['g']
   assertArrayEqual(validateSong({instr: 'not-an-array'}).instr, ['g']);
 });