diff --git a/README.md b/README.md
index 6d26465..608bcac 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,8 @@ Uncompressed MusicXML 3.1/4.0 scores exported from Soundslice or MuseScore live
 
 `data/songs` supplies the authored music. `data/rhythms/<meter>/<series>/` supplies the accompaniment rhythm library for 2/4, 3/4, 4/4, and 5/4. Rhythm snippets are build inputs, not separate catalog entries or runtime files. Generation loads the library once and shares it across parts.
 
+`data/scales` is reserved for unfinished scale sources. These files are not parsed, validated, generated, or packaged, and editing them does not trigger asset regeneration.
+
 To inspect generated assets without building the full package, run:
 
 ```sh
diff --git a/cmake/zero.cmake b/cmake/zero.cmake
index d5bc29d..5924b04 100644
--- a/cmake/zero.cmake
+++ b/cmake/zero.cmake
@@ -139,6 +139,7 @@ file(GLOB_RECURSE VAMP_GENERATOR_INPUTS CONFIGURE_DEPENDS
   ${CMAKE_CURRENT_SOURCE_DIR}/package/assets/fonts/*
   ${CMAKE_CURRENT_SOURCE_DIR}/package/assets/fonts/**/*
 )
+list(FILTER VAMP_GENERATOR_INPUTS EXCLUDE REGEX "/data/scales/")
 set(VAMP_GENERATED_ASSETS_DIR ${CMAKE_CURRENT_BINARY_DIR}/generated-assets)
 set(VAMP_GENERATED_ASSETS_STAMP ${CMAKE_CURRENT_BINARY_DIR}/generated-assets.stamp)
 set(VAMP_ENGRAVING_JOBS 2 CACHE STRING "Maximum parallel Python engraving workers (1-16)")
diff --git a/generator/__main__.py b/generator/__main__.py
index 8edb5ae..2d5d257 100644
--- a/generator/__main__.py
+++ b/generator/__main__.py
@@ -60,7 +60,7 @@ def generate_assets(args: argparse.Namespace) -> None:
 
   report('checking source paths')
   for source in sorted(data_dir.rglob('*.xml')):
-    if source.is_relative_to(data_dir / 'rhythms'):
+    if source.is_relative_to(data_dir / 'rhythms') or source.is_relative_to(data_dir / 'scales'):
       continue
     if source.parent != data_dir / 'songs':
       raise ValueError(f'{source}: MusicXML sources belong directly under data/songs')
diff --git a/tests/test_score_bundle.py b/tests/test_score_bundle.py
index 4c51e43..c3c3902 100644
--- a/tests/test_score_bundle.py
+++ b/tests/test_score_bundle.py
@@ -46,7 +46,8 @@ class ScoreBundleTests(unittest.TestCase):
       original = {p.relative_to(output): p.read_bytes() for p in output.rglob('*') if p.is_file()}
       self.assertTrue(list(output.rglob('*.png')))
       (data / 'rhythms' / 'drafts').mkdir(parents=True)
-      for path in ('rhythms/0001.xml', 'rhythms/drafts/0002.xml'):
+      (data / 'scales' / 'major-scale-modes').mkdir(parents=True)
+      for path in ('rhythms/0001.xml', 'rhythms/drafts/0002.xml', 'scales/0001.xml', 'scales/major-scale-modes/0002.xml'):
         (data / path).write_text('<unfinished')
       generator.__main__.generate_assets(args)
       self.assertEqual(original, {p.relative_to(output): p.read_bytes() for p in output.rglob('*') if p.is_file()})