diff --git a/excore/config/__init__.py b/excore/config/__init__.py
index 7b0fb2c..0030292 100644
--- a/excore/config/__init__.py
+++ b/excore/config/__init__.py
@@ -7,6 +7,7 @@
     ModuleNode,
     ReusedNode,
     VariableReference,
+    register_special_flag,
     silent,
 )
 from .parse import ConfigDict, set_primary_fields
@@ -24,5 +25,6 @@
     "InterNode",
     "ModuleNode",
     "ReusedNode",
+    "register_special_flag",
     "VariableReference",
 ]
diff --git a/excore/config/models.py b/excore/config/models.py
index b45abff..341d87b 100644
--- a/excore/config/models.py
+++ b/excore/config/models.py
@@ -25,7 +25,7 @@
     NoCallSkipFlag = Self
     ConfigHookSkipFlag = Type[None]
 
-    SpecialFlag = Literal["@", "!", "$", "&", "*", ""]
+    SpecialFlag = Literal["@", "!", "$", "&", ""]
 
 
 __all__ = ["silent"]
@@ -34,11 +34,12 @@
 INTER_FLAG: Literal["!"] = "!"
 CLASS_FLAG: Literal["$"] = "$"
 REFER_FLAG: Literal["&"] = "&"
-DETAI_FLAG: Literal["*"] = "*"
 OTHER_FLAG: Literal[""] = ""
 
+FLAG_PATTERN = re.compile(r"^([@!$&])(.*)$")
 LOG_BUILD_MESSAGE = True
 DO_NOT_CALL_KEY = "__no_call__"
+SPECIAL_FLAGS = [OTHER_FLAG, INTER_FLAG, REUSE_FLAG, CLASS_FLAG, REFER_FLAG]
 
 
 def silent() -> None:
@@ -60,8 +61,7 @@ def _is_special(k: str) -> tuple[str, SpecialFlag]:
     Returns:
         Tuple[str, str]: A tuple containing the modified string and the special character.
     """
-    pattern = re.compile(r"^([@!$&*])(.*)$")
-    match = pattern.match(k)
+    match = FLAG_PATTERN.match(k)
     if match:
         return match.group(2), match.group(1)  # type: ignore
     return k, ""
@@ -140,6 +140,10 @@ def __rshift__(self, __other: ModuleNode) -> Self:
         __other.update(self)
         return self
 
+    @classmethod
+    def __excore_check_target_type__(cls, target_type) -> bool:
+        return False
+
     @classmethod
     def from_str(cls, str_target: str, params: NodeParams | None = None) -> ModuleNode:
         node = cls(_str_to_target(str_target))
@@ -171,6 +175,10 @@ def from_node(cls, _other: ModuleNode) -> ModuleNode:
 class InterNode(ModuleNode):
     priority = 2
 
+    @classmethod
+    def __excore_check__(cls, target_type) -> bool:
+        return cls.priority + target_type.priority == 5
+
 
 class ConfigHookNode(ModuleNode):
     def __call__(self, **params: NodeParams) -> NodeInstance | ConfigHookSkipFlag | Hook:
@@ -194,6 +202,10 @@ class ClassNode(InterNode):
     def __call__(self) -> NodeClassType | FunctionType:  # type: ignore
         return self.cls
 
+    @classmethod
+    def __excore_check__(cls, target_type) -> bool:
+        return cls.priority + target_type.priority == 5
+
 
 class ChainedInvocationWrapper(ConfigArgumentHook):
     def __init__(self, node: ModuleNode, attrs: list[str]) -> None:
@@ -300,3 +312,12 @@ def __repr__(self) -> str:
     INTER_FLAG: InterNode,
     CLASS_FLAG: ClassNode,
 }
+
+
+def register_special_flag(flag: str, target_module: ModuleNode, force: bool = False) -> None:
+    if not force and flag in SPECIAL_FLAGS:
+        raise ValueError(f"Special flag `{flag}` already exist.")
+    SPECIAL_FLAGS.append(flag)
+    global FLAG_PATTERN
+    FLAG_PATTERN = re.compile(rf"^([{''.join(SPECIAL_FLAGS)}])(.*)$")
+    _dispatch_module_node[flag] = target_module  # type: ignore
diff --git a/excore/config/parse.py b/excore/config/parse.py
index 5d85dc9..edd794d 100644
--- a/excore/config/parse.py
+++ b/excore/config/parse.py
@@ -370,7 +370,8 @@ def _parse_single_param(
         self.current_field = cache_field
 
         # InterNode and ReusedNode
-        if ori_type and ori_type.priority + target_type.priority == 5:
+        # if ori_type and ori_type.priority + target_type.priority == 5:
+        if ori_type and ori_type.__excore_check_target_type__(target_type):
             raise CoreConfigParseError(
                 f"Error when parsing param `{ori_name}`, "
                 f"target_type is `{target_type}`, but got original_type `{ori_type}`. "