diff --git a/e2e_toy/tests/test_textops.py b/e2e_toy/tests/test_textops.py
index e05680d..fc30909 100644
--- a/e2e_toy/tests/test_textops.py
+++ b/e2e_toy/tests/test_textops.py
@@ -23,6 +23,9 @@ def test_inside(self):
     def test_below(self):
         self.assertEqual(clamp(-3, 0, 10), 0)
 
+    def test_at_upper_bound(self):
+        self.assertEqual(clamp(10, 0, 10), 10)
+
 
 class ChunkTest(unittest.TestCase):
     def test_even(self):
diff --git a/e2e_toy/textops.py b/e2e_toy/textops.py
index 8f71f6c..57feb8d 100644
--- a/e2e_toy/textops.py
+++ b/e2e_toy/textops.py
@@ -19,8 +19,9 @@ def clamp(value, low, high):
     """Limit ``value`` to the closed range [low, high]."""
     if value < low:
         return low
-    if value > high:
-        return value
+    if value >= high:
+        # Values at or above the upper bound are handled here.
+        return max(value, high)
     return value