diff --git a/src/classes/action/assassinate.py b/src/classes/action/assassinate.py
index 7072053..b8a85dd 100644
--- a/src/classes/action/assassinate.py
+++ b/src/classes/action/assassinate.py
@@ -68,7 +68,7 @@ class Assassinate(InstantAction, TargetingMixin):
             
             self._last_result = (winner, loser, loser_damage, winner_damage)
 
-    def can_start(self, avatar_name: str | None = None) -> tuple[bool, str]:
+    def can_start(self, avatar_name: str) -> tuple[bool, str]:
         # 注意：cooldown_action 装饰器会覆盖这个方法并在调用此方法前检查 CD
         _, ok, reason = self.validate_target_avatar(avatar_name)
         return ok, reason
diff --git a/src/classes/action/attack.py b/src/classes/action/attack.py
index 6b892e2..137a2af 100644
--- a/src/classes/action/attack.py
+++ b/src/classes/action/attack.py
@@ -41,7 +41,7 @@ class Attack(InstantAction, TargetingMixin):
         
         self._last_result = (winner, loser, loser_damage, winner_damage)
 
-    def can_start(self, avatar_name: str | None = None) -> tuple[bool, str]:
+    def can_start(self, avatar_name: str) -> tuple[bool, str]:
         _, ok, reason = self.validate_target_avatar(avatar_name)
         return ok, reason
 
diff --git a/src/classes/action/buy.py b/src/classes/action/buy.py
index 0c811fe..ba1e03b 100644
--- a/src/classes/action/buy.py
+++ b/src/classes/action/buy.py
@@ -31,17 +31,11 @@ class Buy(InstantAction):
     DOABLES_REQUIREMENTS = "在城镇且金钱足够"
     PARAMS = {"target_name": "str"}
 
-    def can_start(self, target_name: str | None = None) -> tuple[bool, str]:
+    def can_start(self, target_name: str) -> tuple[bool, str]:
         region = self.avatar.tile.region
         if not isinstance(region, CityRegion):
             return False, "仅能在城市区域执行"
             
-        if target_name is None:
-            # 用于动作空间检查
-            # 理论上只要有钱就可以买东西，这里简单判定金钱>0
-            ok = self.avatar.magic_stone > 0
-            return (ok, "" if ok else "身无分文")
-
         obj, obj_type, display_name = resolve_goods_by_name(target_name)
         if obj_type == "unknown":
             return False, f"未知物品: {target_name}"
diff --git a/src/classes/action/cast.py b/src/classes/action/cast.py
index 729a8c7..42a0c95 100644
--- a/src/classes/action/cast.py
+++ b/src/classes/action/cast.py
@@ -50,7 +50,7 @@ class Cast(TimedAction):
                 count += qty
         return count
 
-    def can_start(self, target_realm: str = "") -> tuple[bool, str]:
+    def can_start(self, target_realm: str) -> tuple[bool, str]:
         if not target_realm:
             return False, "未指定目标境界"
         
@@ -67,7 +67,7 @@ class Cast(TimedAction):
             
         return True, ""
 
-    def start(self, target_realm: str = "") -> Event:
+    def start(self, target_realm: str) -> Event:
         self.target_realm = Realm(target_realm)
         cost = self._get_cost()
         
diff --git a/src/classes/action/escape.py b/src/classes/action/escape.py
index 4b22ad7..b11cc00 100644
--- a/src/classes/action/escape.py
+++ b/src/classes/action/escape.py
@@ -64,7 +64,7 @@ class Escape(InstantAction):
             if start_event is not None:
                 EventHelper.push_pair(start_event, initiator=self.avatar, target=target, to_sidebar_once=True)
 
-    def can_start(self, avatar_name: str | None = None) -> tuple[bool, str]:
+    def can_start(self, avatar_name: str) -> tuple[bool, str]:
         return True, ""
 
     def start(self, avatar_name: str) -> Event:
diff --git a/src/classes/action/move_away_from_avatar.py b/src/classes/action/move_away_from_avatar.py
index d27c9bf..fd875ab 100644
--- a/src/classes/action/move_away_from_avatar.py
+++ b/src/classes/action/move_away_from_avatar.py
@@ -47,7 +47,7 @@ class MoveAwayFromAvatar(TimedAction):
         dx, dy = clamp_manhattan_with_diagonal_priority(raw_dx, raw_dy, step)
         Move(self.avatar, self.world).execute(dx, dy)
 
-    def can_start(self, avatar_name: str | None = None) -> tuple[bool, str]:
+    def can_start(self, avatar_name: str) -> tuple[bool, str]:
         return True, ""
 
     def start(self, avatar_name: str) -> Event:
diff --git a/src/classes/action/move_away_from_region.py b/src/classes/action/move_away_from_region.py
index cb424df..54afddb 100644
--- a/src/classes/action/move_away_from_region.py
+++ b/src/classes/action/move_away_from_region.py
@@ -34,9 +34,7 @@ class MoveAwayFromRegion(InstantAction):
         dx, dy = clamp_manhattan_with_diagonal_priority(away_dx, away_dy, step)
         Move(self.avatar, self.world).execute(dx, dy)
 
-    def can_start(self, region: str | None = None) -> tuple[bool, str]:
-        if region is None:
-            return True, ""
+    def can_start(self, region: str) -> tuple[bool, str]:
         try:
             resolve_region(self.world, region)
             return True, ""
diff --git a/src/classes/action/move_to_avatar.py b/src/classes/action/move_to_avatar.py
index ba2efb3..d27037d 100644
--- a/src/classes/action/move_to_avatar.py
+++ b/src/classes/action/move_to_avatar.py
@@ -42,7 +42,7 @@ class MoveToAvatar(DefineAction, ActualActionMixin):
         dx, dy = clamp_manhattan_with_diagonal_priority(raw_dx, raw_dy, step)
         Move(self.avatar, self.world).execute(dx, dy)
 
-    def can_start(self, avatar_name: str | None = None) -> tuple[bool, str]:
+    def can_start(self, avatar_name: str) -> tuple[bool, str]:
         return True, ""
 
     def start(self, avatar_name: str) -> Event:
diff --git a/src/classes/action/move_to_direction.py b/src/classes/action/move_to_direction.py
index f635520..8fdb3d0 100644
--- a/src/classes/action/move_to_direction.py
+++ b/src/classes/action/move_to_direction.py
@@ -73,9 +73,7 @@ class MoveToDirection(DefineAction, ActualActionMixin):
         self.start_monthstamp = None
         self.direction = None
 
-    def can_start(self, direction: str | None = None) -> tuple[bool, str]:
-        if not direction:
-            return False, "缺少方向参数"
+    def can_start(self, direction: str) -> tuple[bool, str]:
         if not Direction.is_valid(direction):
             return False, f"无效的方向: {direction}"
         return True, ""
diff --git a/src/classes/action/move_to_region.py b/src/classes/action/move_to_region.py
index 5e2b09e..ce773df 100644
--- a/src/classes/action/move_to_region.py
+++ b/src/classes/action/move_to_region.py
@@ -57,9 +57,7 @@ class MoveToRegion(DefineAction, ActualActionMixin):
         dx, dy = clamp_manhattan_with_diagonal_priority(raw_dx, raw_dy, step)
         Move(self.avatar, self.world).execute(dx, dy)
 
-    def can_start(self, region: Region | str | None = None) -> tuple[bool, str]:
-        if region is None:
-            return False, "缺少参数 region"
+    def can_start(self, region: Region | str) -> tuple[bool, str]:
         try:
             r = resolve_region(self.world, region)
             
diff --git a/src/classes/action/sell.py b/src/classes/action/sell.py
index 39df194..503aa2a 100644
--- a/src/classes/action/sell.py
+++ b/src/classes/action/sell.py
@@ -23,18 +23,10 @@ class Sell(InstantAction):
     DOABLES_REQUIREMENTS = "在城镇且持有可出售物品/装备"
     PARAMS = {"target_name": "str"}
 
-    def can_start(self, target_name: str | None = None) -> tuple[bool, str]:
+    def can_start(self, target_name: str) -> tuple[bool, str]:
         region = self.avatar.tile.region
         if not isinstance(region, CityRegion):
             return False, "仅能在城市区域执行"
-            
-        if target_name is None:
-            # 用于动作空间：只要有任何可卖东西即可
-            has_items = bool(self.avatar.items)
-            has_weapon = self.avatar.weapon is not None
-            has_auxiliary = self.avatar.auxiliary is not None
-            ok = has_items or has_weapon or has_auxiliary
-            return (ok, "" if ok else "背包为空且无装备，无可出售物品")
         
         # 使用通用解析逻辑获取物品原型和类型
         obj, obj_type, _ = resolve_goods_by_name(target_name)
diff --git a/src/classes/action/switch_weapon.py b/src/classes/action/switch_weapon.py
index f1729c3..abed81f 100644
--- a/src/classes/action/switch_weapon.py
+++ b/src/classes/action/switch_weapon.py
@@ -47,11 +47,7 @@ class SwitchWeapon(InstantAction):
         # 切换兵器（使用 Avatar 的 change_weapon 方法）
         self.avatar.change_weapon(common_weapon)
 
-    def can_start(self, weapon_type_name: str | None = None) -> tuple[bool, str]:
-        if weapon_type_name is None:
-            # AI调用：总是可以切换兵器
-            return True, ""
-        
+    def can_start(self, weapon_type_name: str) -> tuple[bool, str]:
         # 处理卸下兵器的情况
         if weapon_type_name in ["无", "None", "none", ""]:
             if self.avatar.weapon is None:
diff --git a/src/classes/mutual_action/mutual_action.py b/src/classes/mutual_action/mutual_action.py
index 4a52d9d..c9ff534 100644
--- a/src/classes/mutual_action/mutual_action.py
+++ b/src/classes/mutual_action/mutual_action.py
@@ -136,7 +136,7 @@ class MutualAction(DefineAction, LLMAction, ActualActionMixin, TargetingMixin):
         pass
 
     # 实现 ActualActionMixin 接口
-    def can_start(self, target_avatar: "Avatar|str|None" = None) -> tuple[bool, str]:
+    def can_start(self, target_avatar: "Avatar|str") -> tuple[bool, str]:
         """
         检查互动动作能否启动：目标需在发起者的交互范围内。
         子类通过实现 _can_start 来添加额外检查。
@@ -144,8 +144,6 @@ class MutualAction(DefineAction, LLMAction, ActualActionMixin, TargetingMixin):
         注意：此方法未使用 TargetingMixin.validate_target_avatar()，
         因为需要额外检查 target == self.avatar 和调用子类的 _can_start()。
         """
-        if target_avatar is None:
-            return False, "缺少参数 target_avatar"
         target = self._get_target_avatar(target_avatar)
         if target is None:
             return False, "目标不存在"