diff --git a/.vscode/settings.json b/.vscode/settings.json
index 100eba6..e548495 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -17,6 +17,9 @@
 	"editor.renderWhitespace": "all",
 	"editor.rulers": [ 76 ],
 	"editor.tabSize": 2,
+	"files.insertFinalNewline": true,
+	"files.trimTrailingWhitespace": true,
+	"git.mergeEditor": false,
 	"files.exclude": {
 		"**/__pycache__": true,
 		"**/*.egg-info": true,
diff --git a/CHANGES.md b/CHANGES.md
index 664b2f5..19ff324 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,6 +1,12 @@
 # **CLASP.Python** Changes <!-- omit from toc -->
 
 
+## 0.8.12 - 28th July 2026
+
+* fixed falsy default values causing `MissingValueException` for option arguments;
+* fixed failure message to be passed to `MissingValueException`;
+
+
 ## 0.8.11 - 27th July 2026
 
 * ~ packaging & boilerplate improvements:
diff --git a/pyclasp/__init__.py b/pyclasp/__init__.py
index 7d1f47d..30977d0 100644
--- a/pyclasp/__init__.py
+++ b/pyclasp/__init__.py
@@ -10,7 +10,7 @@
 __license__     =   "BSD-3-Clause"
 __maintainer__  =   "Matt Wilson"
 __status__      =   "Beta"
-__version__     =   "0.8.11"
+__version__     =   "0.8.12"
 
 from .exceptions import *
 from .flag_specification import FlagSpecification, flag
diff --git a/pyclasp/option_argument.py b/pyclasp/option_argument.py
index 7b5531e..67ab05f 100644
--- a/pyclasp/option_argument.py
+++ b/pyclasp/option_argument.py
@@ -85,7 +85,7 @@ def _set_value(self, value, from_ctor=False):
 
                 given_value = arg_spec.default_value
 
-            if given_value:
+            if given_value is not None:
 
 
                 if arg_spec.value_type:
@@ -148,7 +148,23 @@ def _set_value(self, value, from_ctor=False):
                         pass
                     else:
 
-                        raise MissingValueException("the '%s' option does not have a value to be interpreted as an integer" % (self.name))
+                        if arg_spec.value_type == bool:
+
+                            type_name = "boolean"
+                        elif arg_spec.value_type == float:
+
+                            type_name = "a number"
+                        elif arg_spec.value_type == int:
+
+                            type_name = "an integer"
+                        elif _SUPPORT_long and arg_spec.value_type == long:
+
+                            type_name = "a long integer"
+                        else:
+
+                            type_name = "a value"
+
+                        raise MissingValueException("the '%s' option does not have a value to be interpreted as %s" % (self.name, type_name))
 
 
         self.given_value    =   given_value
diff --git a/setup.py b/setup.py
index 1901d62..d394e62 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@
 
     name="pyclasp",
     python_requires='>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, !=3.5.*, !=3.6.*, !=3.7.*',
-    version='0.8.11',
+    version='0.8.12',
 
     author="Matt Wilson",
     author_email="matthew@synesis.com.au",
diff --git a/tests/test_typed_values.py b/tests/test_typed_values.py
index 308bbe4..3ca005b 100755
--- a/tests/test_typed_values.py
+++ b/tests/test_typed_values.py
@@ -303,10 +303,44 @@ def test_empty_option_value_of_type_int(self):
 
         argv    =   ( "myprog", "--length=" )
 
-        with self.assertRaises(clasp.MissingValueException):
+        with self.assertRaises(clasp.MissingValueException) as ctx:
 
             clasp.parse(argv, specifications)
 
+        self.assertEqual("the '--length' option does not have a value to be interpreted as an integer", str(ctx.exception))
+
+
+    def test_empty_option_value_of_type_float(self):
+
+        specifications =   (
+
+            clasp.option('--length', alias='-l', value_type=float),
+        )
+
+        argv    =   ( 'myprog', '--length=' )
+
+        with self.assertRaises(clasp.MissingValueException) as ctx:
+
+            clasp.parse(argv, specifications)
+
+        self.assertEqual("the '--length' option does not have a value to be interpreted as a number", str(ctx.exception))
+
+
+    def test_empty_option_value_of_type_bool(self):
+
+        specifications =   (
+
+            clasp.option('--length', alias='-l', value_type=bool),
+        )
+
+        argv    =   ( 'myprog', '--length=' )
+
+        with self.assertRaises(clasp.MissingValueException) as ctx:
+
+            clasp.parse(argv, specifications)
+
+        self.assertEqual("the '--length' option does not have a value to be interpreted as boolean", str(ctx.exception))
+
 
     def test_empty_option_value_of_type_int_2(self):
 
@@ -442,6 +476,61 @@ def test_flags_of_flags_and_options_combined(self):
         self.assertEqual(0, len(args.values))
 
 
+    def test_reproduce_falsy_default_issue(self):
+
+        specifications = (
+            clasp.option(
+                "--depth",
+                alias="-d",
+                default=0,
+                value_type=int,
+            ),
+            clasp.option(
+                "--exchange",
+                alias="-e",
+                required=True,
+                value_type=str,
+            ),
+        )
+
+        argv = ('liquidity-assessor', '-e', 'bybit', '-d', '10')
+        args = clasp.parse(argv, specifications)
+
+        self.assertEqual(2, len(args.options))
+
+        depth_option = next(opt for opt in args.options if opt.name == '--depth')
+        self.assertEqual(10, depth_option.value)
+
+        exchange_option = next(opt for opt in args.options if opt.name == '--exchange')
+        self.assertEqual('bybit', exchange_option.value)
+
+
+    def test_reproduce_falsy_default_issue_with_default_used(self):
+
+        specifications = (
+            clasp.option(
+                "--depth",
+                alias="-d",
+                default=0,
+                value_type=int,
+            ),
+            clasp.option(
+                "--exchange",
+                alias="-e",
+                required=True,
+                value_type=str,
+            ),
+        )
+
+        argv = ('liquidity-assessor', '-e', 'bybit')
+        args = clasp.parse(argv, specifications)
+
+        # In CLASP, options with defaults are not automatically added to args.options unless specified on the CLI or if we lookup/access them?
+        # Wait, let's verify if they are added or not.
+        self.assertEqual(1, len(args.options))
+        exchange_option = args.options[0]
+        self.assertEqual('bybit', exchange_option.value)
+
 
 if '__main__' == __name__: