diff --git a/src/ffmpeg/common/schema.py b/src/ffmpeg/common/schema.py
index e8dfb673..fc7970c8 100644
--- a/src/ffmpeg/common/schema.py
+++ b/src/ffmpeg/common/schema.py
@@ -107,6 +107,7 @@ class FFMpegFilter:
     formula_typings_input: str | None = None
     formula_typings_output: str | None = None
 
+    pre: tuple[tuple[str, str], ...] = ()
     options: tuple[FFMpegFilterOption, ...] = ()
 
     @property
diff --git a/src/scripts/cache.py b/src/scripts/cache.py
index 2b7178b5..63f11f4a 100644
--- a/src/scripts/cache.py
+++ b/src/scripts/cache.py
@@ -23,3 +23,9 @@ def save(obj: T, id: str) -> None:
 
     with (schema_path / f"{id}.json").open("w") as ofile:
         ofile.write(dumps(obj))
+
+
+def list_all(cls: type[T]) -> list[T]:
+    path = cache_path / f"{cls.__name__}"
+
+    return [loads(i.read_text()) for i in path.glob("*.json")]
diff --git a/src/scripts/manual/schema.py b/src/scripts/manual/schema.py
index c258a5a9..1cc2dc4f 100644
--- a/src/scripts/manual/schema.py
+++ b/src/scripts/manual/schema.py
@@ -1,6 +1,12 @@
 from dataclasses import dataclass
 
 
+@dataclass(kw_only=True, frozen=True)
+class FFMpegFilterManuallyDefinedHook:
+    name: str
+    function: str
+
+
 @dataclass(kw_only=True)
 class FFMpegFilterManuallyDefined:
     name: str
@@ -8,4 +14,4 @@ class FFMpegFilterManuallyDefined:
     formula_typings_input: str | None = None
     formula_typings_output: str | None = None
 
-    pre: dict[str, str] = {}
+    pre: tuple[tuple[str, str], ...] = ()
diff --git a/src/scripts/tests/__snapshots__/test_cache.ambr b/src/scripts/tests/__snapshots__/test_cache.ambr
new file mode 100644
index 00000000..2c80fb1c
--- /dev/null
+++ b/src/scripts/tests/__snapshots__/test_cache.ambr
@@ -0,0 +1,6 @@
+# serializer version: 1
+# name: test_save_and_load
+  list([
+    FFMpegFilter(id=None, name='foo', description='bar', ref=None, is_support_slice_threading=None, is_support_timeline=None, is_support_framesync=None, is_support_command=None, is_filter_sink=None, is_filter_source=None, is_dynamic_input=False, is_dynamic_output=False, stream_typings_input=(), stream_typings_output=(), formula_typings_input=None, formula_typings_output=None, pre=(), options=()),
+  ])
+# ---
diff --git a/src/scripts/tests/test_cache.py b/src/scripts/tests/test_cache.py
index aa78a6b5..3eae55cf 100644
--- a/src/scripts/tests/test_cache.py
+++ b/src/scripts/tests/test_cache.py
@@ -1,10 +1,14 @@
+from syrupy.assertion import SnapshotAssertion
+
 from ffmpeg.common.schema import FFMpegFilter
 
-from ..cache import load, save
+from ..cache import list_all, load, save
 
 
-def test_save_and_load() -> None:
+def test_save_and_load(snapshot: SnapshotAssertion) -> None:
     ffmpeg_filter = FFMpegFilter(name="foo", description="bar")
     save(ffmpeg_filter, ffmpeg_filter.name)
 
     assert load(FFMpegFilter, ffmpeg_filter.name) == ffmpeg_filter
+
+    assert snapshot == list_all(FFMpegFilter)