diff --git a/tests/test_config.py b/tests/test_config.py
index 361b9bd..bb8aa47 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -402,12 +402,12 @@ def test_prefix_error():
     try:
         cfg.option('test1').value.set('yes')
     except Exception as err:
-        assert str(err) == _('"{0}" is an invalid {1} for "{2}", which is not an integer').format('yes', _('integer'), 'test1')
+        assert str(err) == _('"{0}" is an invalid {1} for "{2}", it\'s not an integer').format('yes', _('integer'), 'test1')
     try:
         cfg.option('test1').value.set('yes')
     except Exception as err:
         err.prefix = ''
-        assert str(err) == _('which is not an integer')
+        assert str(err) == _('it\'s not an integer')
 #    assert not list_sessions()
 
 
diff --git a/tiramisu/api.py b/tiramisu/api.py
index 78b44a2..1fefb10 100644
--- a/tiramisu/api.py
+++ b/tiramisu/api.py
@@ -583,6 +583,7 @@ class _TiramisuOptionOptionDescription:
         convert: bool = False,
     ):
         """Get identifiers for dynamic option"""
+        subconfig = self._subconfig
         if not only_self:
             if self._subconfig.is_dynamic_without_identifiers and not uncalculated:
                 raise AttributeOptionError(self._subconfig.path, "option-dynamic")
@@ -590,7 +591,6 @@ class _TiramisuOptionOptionDescription:
                 return self._subconfig.identifiers
             identifiers = []
             dynconfig = None
-            subconfig = self._subconfig
             while not dynconfig:
                 if subconfig.option.impl_is_optiondescription() and subconfig.option.impl_is_dynoptiondescription():
                     dynconfig = subconfig
@@ -607,7 +607,8 @@ class _TiramisuOptionOptionDescription:
             raise ConfigError(
                 _(
                     "the option {0} is not a dynamic option, cannot get identifiers with only_self parameter to True"
-                ).format(self._subconfig.path)
+                ).format(self._subconfig.path),
+                subconfig=subconfig,
             )
         return self._subconfig.option.get_identifiers(
             self._subconfig.parent,
diff --git a/tiramisu/autolib.py b/tiramisu/autolib.py
index 1ef4bdf..de3efdb 100644
--- a/tiramisu/autolib.py
+++ b/tiramisu/autolib.py
@@ -462,7 +462,7 @@ def manager_callback(
                 or param.raisepropertyerror
             ):
                 raise err from err
-            raise ConfigError(err)
+            raise ConfigError(err, subconfig=subconfig)
         except ValueError as err:
             display_name = subconfig.option.impl_get_display_name(
                 subconfig, with_quote=True
@@ -626,7 +626,7 @@ def manager_callback(
             properties = config_bag.context.get_settings().getproperties(
                 subconfig,
                 uncalculated=True,
-            ) - {'validator'}
+            ) - {'validator', 'mandatory', 'empty'}
             for subconfig_ in subconfigs:
                 if subconfig.path == subconfig_.path:
                     values.append(orig_value)
@@ -958,6 +958,7 @@ def calculate(
             raise err from err
         error = err
     except ConfigError as err:
+        err.subconfig = subconfig
         raise err from err
     except Exception as err:
         error = err
diff --git a/tiramisu/config.py b/tiramisu/config.py
index 0965832..9868777 100644
--- a/tiramisu/config.py
+++ b/tiramisu/config.py
@@ -522,7 +522,7 @@ class SubConfig:
         )
         if check_index and index is not None:
             if option.impl_is_optiondescription() or not option.impl_is_follower():
-                raise ConfigError("index must be set only with a follower option")
+                raise ConfigError("index must be set only with a follower option", subconfig=subsubconfig,)
             length = self.get_length_leadership()
             if index >= length:
                 raise LeadershipError(
@@ -1426,7 +1426,7 @@ class KernelGroupConfig(_CommonConfig):
                     # pylint: disable=protected-access
                     ret.append(
                         PropertiesOptionError(
-                            err._subconfig,
+                            err.subconfig,
                             err.proptype,
                             err._settings,
                             err._opt_type,
@@ -1674,7 +1674,7 @@ class KernelMixConfig(KernelGroupConfig):
                         # pylint: disable=protected-access
                         ret.append(
                             PropertiesOptionError(
-                                err._subconfig,
+                                err.subconfig,
                                 err.proptype,
                                 err._settings,
                                 err._opt_type,
diff --git a/tiramisu/error.py b/tiramisu/error.py
index 38e2e18..dd2607e 100644
--- a/tiramisu/error.py
+++ b/tiramisu/error.py
@@ -18,7 +18,7 @@
 import weakref
 from .i18n import _
 
-from typing import Literal, Union
+from typing import Literal, Union, Optional
 
 
 TiramisuErrorCode = Literal[
@@ -101,7 +101,7 @@ class PropertiesOptionError(AttributeError):
                 subconfig, with_quote=True
             )
             self._orig_opt = None
-        self._subconfig = subconfig
+        self.subconfig = subconfig
         self.proptype = proptype
         self.help_properties = help_properties
         self._settings = settings
@@ -136,7 +136,7 @@ class PropertiesOptionError(AttributeError):
                 self._orig_opt.impl_get_display_name(subconfig, with_quote=True)
             )
         arguments.append(self._name)
-        index = self._subconfig.index
+        index = self.subconfig.index
         if index is not None:
             arguments.append(index)
         if self.code == "property-frozen":
@@ -215,10 +215,22 @@ class ConfigError(Exception):
     def __init__(
         self,
         exp,
-        ori_err=None,
+        *,
+        prefix: Optional[str] = None,
+        subconfig: Optional["Subconfig"]=None,
     ):
         super().__init__(exp)
-        self.ori_err = ori_err
+        self.err_msg = exp
+        self.subconfig = subconfig
+        self.prefix = prefix
+
+    def __str__(self):
+        msg = self.prefix
+        if msg:
+            msg += ", {}".format(self.err_msg)
+        else:
+            msg = self.err_msg
+        return msg
 
 
 class ConflictError(Exception):
@@ -419,9 +431,9 @@ class Errors:
         display_name = option.impl_get_display_name(subconfig, with_quote=True)
         if original_error:
             raise ConfigError(
-                message.format(display_name, original_error, *extra_keys)
+                message.format(display_name, original_error, *extra_keys), subconfig=subconfig,
             ) from original_error
-        raise ConfigError(message.format(display_name, extra_keys))
+        raise ConfigError(message.format(display_name, extra_keys), subconfig=subconfig)
 
 
 errors = Errors()
diff --git a/tiramisu/option/baseoption.py b/tiramisu/option/baseoption.py
index b8df7de..19ab5ef 100644
--- a/tiramisu/option/baseoption.py
+++ b/tiramisu/option/baseoption.py
@@ -395,6 +395,8 @@ class BaseOption(Base):
         is_identifier: bool = False,
         type_: str = 'default'
     ) -> Any:
+        if not isinstance(is_identifier, bool):
+            raise Exception()
         """parse dependancy to add dependencies"""
         for param in chain(value.params.args, value.params.kwargs.values()):
             if isinstance(param, ParamOption):
diff --git a/tiramisu/option/choiceoption.py b/tiramisu/option/choiceoption.py
index 5965225..b04d647 100644
--- a/tiramisu/option/choiceoption.py
+++ b/tiramisu/option/choiceoption.py
@@ -45,7 +45,7 @@ class ChoiceOption(Option):
         :param values: is a list of values the option can possibly take
         """
         if isinstance(values, Calculation):
-            self.value_dependency(values, "choice")
+            self.value_dependency(values, type_="choice")
         elif not isinstance(values, tuple):
             raise TypeError(
                 _("values must be a tuple or a calculation for {0}").format(name)
@@ -73,7 +73,8 @@ class ChoiceOption(Option):
             raise ConfigError(
                 _('the calculated values "{0}" for "{1}" is not a list' "").format(
                     values, self.impl_getname()
-                )
+                ),
+                subconfig=subconfig,
             )
         return values
 
diff --git a/tiramisu/option/dynoptiondescription.py b/tiramisu/option/dynoptiondescription.py
index 691a691..afaf7f6 100644
--- a/tiramisu/option/dynoptiondescription.py
+++ b/tiramisu/option/dynoptiondescription.py
@@ -31,7 +31,6 @@ from ..i18n import _
 from .optiondescription import OptionDescription
 from .baseoption import BaseOption
 from ..setting import ConfigBag, undefined
-from ..error import ConfigError
 from ..autolib import Calculation, get_calculated_value
 
 
diff --git a/tiramisu/option/intoption.py b/tiramisu/option/intoption.py
index 19545bd..3701a9b 100644
--- a/tiramisu/option/intoption.py
+++ b/tiramisu/option/intoption.py
@@ -56,7 +56,7 @@ class IntOption(Option):
         value: int,
     ) -> None:
         if not isinstance(value, int):
-            raise ValueError(_("which is not an integer"))
+            raise ValueError(_("it's not an integer"))
 
     def second_level_validation(self, value, warnings_only):
         min_integer = self.impl_get_extra("min_integer")
diff --git a/tiramisu/option/stroption.py b/tiramisu/option/stroption.py
index 2b77685..f47825e 100644
--- a/tiramisu/option/stroption.py
+++ b/tiramisu/option/stroption.py
@@ -39,7 +39,7 @@ class StrOption(Option):
     ) -> None:
         """validation"""
         if not isinstance(value, str):
-            raise ValueError(_("which is not a string"))
+            raise ValueError(_("it's not a string"))
 
 
 class RegexpOption(StrOption):
diff --git a/tiramisu/option/symlinkoption.py b/tiramisu/option/symlinkoption.py
index 290b804..9b54f12 100644
--- a/tiramisu/option/symlinkoption.py
+++ b/tiramisu/option/symlinkoption.py
@@ -22,7 +22,6 @@
 """
 from typing import Any, Optional, Dict
 from .baseoption import BaseOption, valid_name
-from ..error import ConfigError
 from ..i18n import _
 
 
diff --git a/tiramisu/setting.py b/tiramisu/setting.py
index 2e7a2e2..23df689 100644
--- a/tiramisu/setting.py
+++ b/tiramisu/setting.py
@@ -638,7 +638,8 @@ class Settings:
             raise ConfigError(
                 _("cannot add those permissives: {0}").format(
                     " ".join(forbidden_permissives)
-                )
+                ),
+                subconfig=subconfig,
             )
         self._permissives.setdefault(path, {})[index] = permissives
         if subconfig is not None:
diff --git a/tiramisu/value.py b/tiramisu/value.py
index 7fd4bc0..00f010d 100644
--- a/tiramisu/value.py
+++ b/tiramisu/value.py
@@ -615,7 +615,8 @@ class Values:
             raise ConfigError(
                 _(
                     '"{0}" is a default value, so we cannot change owner to "{1}"'
-                ).format(subconfig.path, owner)
+                ).format(subconfig.path, owner),
+                subconfig=subconfig,
             )
         subconfig.config_bag.context.get_settings().validate_frozen(subconfig)
         self._values[subconfig.path][subconfig.index][1] = owner