diff --git a/tests/test_manage_set.py b/tests/test_manage_set.py
index c7714d7c..c035cd26 100644
--- a/tests/test_manage_set.py
+++ b/tests/test_manage_set.py
@@ -98,6 +98,54 @@ class SetValueTest(unittest.TestCase):
         self.assertIn("columns", refusal)
         self.assertIsNone(self.written())
 
+    def test_a_number_key_refuses_a_value_outside_the_tables_range(self):
+        # integer() keeps its own default for a number outside min..max, so set must not write one either.
+        for key, value in (("columns", "9"), ("columns", "0"), ("rows_below_dock", "4"),
+                           ("sky_intensity", "101"), ("clock_wallpaper_dim", "91"), ("dock_opacity", "29")):
+            with self.subTest(key=key, value=value):
+                self.config.unlink(missing_ok=True)
+                refusal = self.set_key(key, value)
+                self.assertIn(key, refusal)
+                self.assertIn("out of range", refusal)
+                self.assertIn(value, refusal)
+                self.assertIsNone(self.written(), "a refused value must not touch the theme")
+                self.push.assert_not_called()
+
+    def test_a_number_key_takes_both_ends_of_its_range(self):
+        # The bounds are read out of the Keys table, so a range that moves there moves here with it.
+        numbers = {k: v for k, v in keys_table_types().items() if manage.declared_kind({"type": v}) == "number"}
+        self.assertGreaterEqual(len(numbers), 10, "the Keys table's number keys were read")
+        for key, cell in sorted(numbers.items()):
+            low, high = manage.declared_range(cell)
+            with self.subTest(key=key, value=low):
+                self.config.unlink(missing_ok=True)
+                self.assertIsNone(self.set_key(key, str(low)))
+                self.assertEqual(low, self.written()[key])
+            with self.subTest(key=key, value=high):
+                self.assertIsNone(self.set_key(key, str(high)))
+                self.assertEqual(high, self.written()[key])
+
+    def test_a_number_key_writes_the_int_the_launcher_would_read(self):
+        # integer() does ((Number) v).intValue(), so 8.9 is eight columns on the TV: write 8, not 8.9.
+        self.assertIsNone(self.set_key("columns", "8.9"))
+        self.assertEqual(8, self.written()["columns"])
+        self.assertIsInstance(self.written()["columns"], int)
+
+    def test_a_number_key_refuses_nan_and_infinity(self):
+        # json.loads accepts these three; intValue() has no answer for them, so the key keeps its default.
+        for text in ("NaN", "Infinity", "-Infinity"):
+            with self.subTest(value=text):
+                self.config.unlink(missing_ok=True)
+                self.assertIn("finite", self.set_key("columns", text))
+                self.assertIsNone(self.written())
+                self.push.assert_not_called()
+
+    def test_a_range_cell_is_read_as_its_two_bounds(self):
+        self.assertEqual((1, 8), manage.declared_range("1 to 8"))
+        self.assertEqual((30, 100), manage.declared_range("30 to 100"))
+        self.assertEqual((None, None), manage.declared_range("bool"))
+        self.assertEqual((None, None), manage.declared_range("1 to 8 if top_menu"))
+
     def test_an_object_key_refuses_a_word_and_takes_a_json_object(self):
         refusal = self.set_key("wallpaper_moods", "nope")
         self.assertIn("wallpaper_moods", refusal)
@@ -151,6 +199,10 @@ class SetValueTest(unittest.TestCase):
         self.assertIn("return v instanceof Boolean ? (Boolean) v : fallback;", config)
         self.assertIn('return v instanceof String ? ((String) v).trim() : fallback;', config)
         self.assertIn("if (!(v instanceof Number)) return fallback;", config)
+        # integer() truncates like Number.intValue() and keeps its default outside min..max: the two rules
+        # set's number handling copies.
+        self.assertIn("int i = ((Number) v).intValue();", config)
+        self.assertIn("return i < min || i > max ? fallback : i;", config)
 
 
 if __name__ == "__main__":
diff --git a/tools/manage.py b/tools/manage.py
index aa6d605e..84b0d407 100644
--- a/tools/manage.py
+++ b/tools/manage.py
@@ -14,9 +14,11 @@ build-and-install.sh, or the steps in addons/README.md; tools/theme.sh for theme
 install on an installed add-on updates it (pm install -r). set writes the key into a theme folder of your own and
 pushes it with tools/theme.sh, as themes/README.md describes; it never edits the project's themes. set reads the
 value the way the key's own type in the Keys table needs - true or false for a bool, a JSON list, object or number
-where the table says so, the text itself for a string - and refuses one the launcher would ignore.
+where the table says so, the text itself for a string - and refuses one the launcher would ignore or a number
+outside the range the table states.
 """
 import json
+import math
 import os
 import re
 import subprocess
@@ -156,11 +158,39 @@ def declared_kind(item):
         return "list"
     if cell == "object":
         return "object"
-    if re.fullmatch(r"\d+(?:\.\d+)? to \d+(?:\.\d+)?", cell):
+    if declared_range(cell) != (None, None):
         return "number"
     return "string" if cell else None
 
 
+def declared_range(cell):
+    """The (low, high) of a range cell such as '1 to 8', or (None, None) when the cell is not a range."""
+    m = re.fullmatch(r"(-?\d+) to (-?\d+)", cell or "")
+    return (int(m.group(1)), int(m.group(2))) if m else (None, None)
+
+
+def number_in_range(key, item, parsed, text):
+    """An int the launcher's integer() would keep: truncated like Number.intValue(), inside the table's range.
+
+    integer() is `int i = ((Number) v).intValue(); return i < min || i > max ? fallback : i;`, so a float is
+    truncated on the TV and anything outside the range is silently the default. The range comes from the Keys
+    table, so the value set writes is one the launcher reads back. (lunar_utc_offset's floor in Config.java is
+    -1, the "by locale" sentinel the table's Meaning column calls Unset rather than a number to pass.)
+    """
+    cell = (item.get("type") or "").strip()
+    low, high = declared_range(cell)
+    if low is None or high is None:
+        # declared_kind() only sends a range cell here; a cell whose shape changed must not pass unchecked.
+        sys.exit(f"{key} has no range in the Keys table, so there is nothing to check {text} against")
+    # json.loads accepts NaN and Infinity; int() has no answer for them and integer() keeps the default.
+    if isinstance(parsed, float) and not math.isfinite(parsed):
+        sys.exit(f"{key} takes {cell}, so pass a finite number, not {text}")
+    value = int(parsed)
+    if not low <= value <= high:
+        sys.exit(f"{key} takes {cell}, so {text} is out of range and the launcher would keep the default")
+    return value
+
+
 def value_as(key, item, text):
     """The argument read the way the key's type needs, or a refusal naming what the key takes."""
     kind = declared_kind(item)
@@ -186,6 +216,8 @@ def value_as(key, item, text):
     if not isinstance(parsed, wanted) or isinstance(parsed, bool):
         example = {"list": '["a", "b"]', "object": '{"key": "value"}', "number": "6"}[kind]
         sys.exit(f"{key} takes {item.get('type')}, so pass {example}, not {text}")
+    if kind == "number":
+        return number_in_range(key, item, parsed, text)
     return parsed