diff --git a/nonebot/__init__.py b/nonebot/__init__.py
index 7d49a9aa..5e7a2034 100644
--- a/nonebot/__init__.py
+++ b/nonebot/__init__.py
@@ -201,4 +201,6 @@ def run(host: Optional[str] = None,
     get_driver().run(host, port, *args, **kwargs)
 
 
-from nonebot.plugin import load_plugin, load_plugins, get_loaded_plugins
+from nonebot.plugin import on_message, on_notice, on_request, on_metaevent
+from nonebot.plugin import on_startswith, on_endswith, on_command, on_regex
+from nonebot.plugin import load_plugin, load_plugins, load_builtin_plugins, get_loaded_plugins
diff --git a/nonebot/plugin.py b/nonebot/plugin.py
index b71f1f61..6241687d 100644
--- a/nonebot/plugin.py
+++ b/nonebot/plugin.py
@@ -10,8 +10,9 @@ from importlib._bootstrap import _load
 from nonebot.log import logger
 from nonebot.matcher import Matcher
 from nonebot.permission import Permission
+from nonebot.typing import Handler, RuleChecker
 from nonebot.rule import Rule, startswith, endswith, command, regex
-from nonebot.typing import Set, Dict, Type, Tuple, Union, Optional, ModuleType, RuleChecker
+from nonebot.typing import Set, List, Dict, Type, Tuple, Union, Optional, ModuleType
 
 plugins: Dict[str, "Plugin"] = {}
 
@@ -20,10 +21,9 @@ _tmp_matchers: Set[Type[Matcher]] = set()
 
 class Plugin(object):
 
-    # TODO: store plugin informations
-    def __init__(self, module_path: str, module: ModuleType,
+    def __init__(self, name: str, module: ModuleType,
                  matchers: Set[Type[Matcher]]):
-        self.module_path = module_path
+        self.name = name
         self.module = module
         self.matchers = matchers
 
@@ -31,7 +31,7 @@ class Plugin(object):
 def on(rule: Union[Rule, RuleChecker] = Rule(),
        permission: Permission = Permission(),
        *,
-       handlers: Optional[list] = None,
+       handlers: Optional[List[Handler]] = None,
        temp: bool = False,
        priority: int = 1,
        block: bool = False,
@@ -50,7 +50,7 @@ def on(rule: Union[Rule, RuleChecker] = Rule(),
 
 def on_metaevent(rule: Union[Rule, RuleChecker] = Rule(),
                  *,
-                 handlers: Optional[list] = None,
+                 handlers: Optional[List[Handler]] = None,
                  temp: bool = False,
                  priority: int = 1,
                  block: bool = False,
@@ -70,7 +70,7 @@ def on_metaevent(rule: Union[Rule, RuleChecker] = Rule(),
 def on_message(rule: Union[Rule, RuleChecker] = Rule(),
                permission: Permission = Permission(),
                *,
-               handlers: Optional[list] = None,
+               handlers: Optional[List[Handler]] = None,
                temp: bool = False,
                priority: int = 1,
                block: bool = True,
@@ -89,7 +89,7 @@ def on_message(rule: Union[Rule, RuleChecker] = Rule(),
 
 def on_notice(rule: Union[Rule, RuleChecker] = Rule(),
               *,
-              handlers: Optional[list] = None,
+              handlers: Optional[List[Handler]] = None,
               temp: bool = False,
               priority: int = 1,
               block: bool = False,
@@ -108,7 +108,7 @@ def on_notice(rule: Union[Rule, RuleChecker] = Rule(),
 
 def on_request(rule: Union[Rule, RuleChecker] = Rule(),
                *,
-               handlers: Optional[list] = None,
+               handlers: Optional[List[Handler]] = None,
                temp: bool = False,
                priority: int = 1,
                block: bool = False,
@@ -149,9 +149,19 @@ def on_command(cmd: Union[str, Tuple[str, ...]],
                **kwargs) -> Type[Matcher]:
     if isinstance(cmd, str):
         cmd = (cmd,)
-    return on_message(command(cmd) &
-                      rule, permission, **kwargs) if rule else on_message(
-                          command(cmd), permission, **kwargs)
+
+    async def _strip_cmd(bot, event, state: dict):
+        message = event.message
+        event.message = message.__class__(
+            str(message)[len(state["_prefix"]["raw_command"]):].strip())
+
+    handlers = kwargs.pop("handlers", [])
+    handlers.insert(0, _strip_cmd)
+
+    return on_message(
+        command(cmd) &
+        rule, permission, handlers=handlers, **kwargs) if rule else on_message(
+            command(cmd), permission, handlers=handlers, **kwargs)
 
 
 def on_regex(pattern: str,
@@ -167,12 +177,20 @@ def on_regex(pattern: str,
 def load_plugin(module_path: str) -> Optional[Plugin]:
     try:
         _tmp_matchers.clear()
+        if module_path in plugins:
+            return plugins[module_path]
+        elif module_path in sys.modules:
+            logger.warning(
+                f"Module {module_path} has been loaded by other plugins! Ignored"
+            )
+            return
         module = importlib.import_module(module_path)
         for m in _tmp_matchers:
             m.module = module_path
         plugin = Plugin(module_path, module, _tmp_matchers.copy())
         plugins[module_path] = plugin
-        logger.opt(colors=True).info(f'Succeeded to import "{module_path}"')
+        logger.opt(
+            colors=True).info(f'Succeeded to import "<y>{module_path}</y>"')
         return plugin
     except Exception as e:
         logger.opt(colors=True, exception=e).error(
@@ -189,7 +207,11 @@ def load_plugins(*plugin_dir: str) -> Set[Plugin]:
             continue
 
         spec = module_info.module_finder.find_spec(name)
-        if spec.name in sys.modules:
+        if spec.name in plugins:
+            continue
+        elif spec.name in sys.modules:
+            logger.warning(
+                f"Module {spec.name} has been loaded by other plugin! Ignored")
             continue
 
         try:
@@ -207,5 +229,9 @@ def load_plugins(*plugin_dir: str) -> Set[Plugin]:
     return loaded_plugins
 
 
+def load_builtin_plugins():
+    return load_plugin("nonebot.plugins.base")
+
+
 def get_loaded_plugins() -> Set[Plugin]:
     return set(plugins.values())
diff --git a/nonebot/plugins/base.py b/nonebot/plugins/base.py
new file mode 100644
index 00000000..de743d14
--- /dev/null
+++ b/nonebot/plugins/base.py
@@ -0,0 +1,10 @@
+from nonebot.rule import to_me
+from nonebot.plugin import on_command
+from nonebot.typing import Bot, Event
+
+say = on_command("say", to_me())
+
+
+@say.handle()
+async def repeat(bot: Bot, event: Event, state: dict):
+    await bot.send(message=event.message, event=event)
diff --git a/nonebot/rule.py b/nonebot/rule.py
index 34c1c7b4..a992e488 100644
--- a/nonebot/rule.py
+++ b/nonebot/rule.py
@@ -74,13 +74,21 @@ class TrieRule:
             suffix = cls.suffix.longest_prefix(
                 message_r.data["text"].rstrip()[::-1])
 
-        state["_prefix"] = {prefix.key: prefix.value} if prefix else {}
-        state["_suffix"] = {suffix.key: suffix.value} if suffix else {}
+        state["_prefix"] = {
+            "raw_command": prefix.key,
+            "command": prefix.value
+        } if prefix else {}
+        state["_suffix"] = {
+            "raw_command": suffix.key,
+            "command": suffix.value
+        } if suffix else {}
 
         return ({
-            prefix.key: prefix.value
+            "raw_command": prefix.key,
+            "command": prefix.value
         } if prefix else {}, {
-            suffix.key: suffix.value
+            "raw_command": suffix.key,
+            "command": suffix.value
         } if suffix else {})
 
 
@@ -122,7 +130,7 @@ def command(command: Tuple[str, ...]) -> Rule:
             TrieRule.add_prefix(f"{start}{sep.join(command)}", command)
 
     async def _command(bot: Bot, event: Event, state: dict) -> bool:
-        return command in state["_prefix"].values()
+        return command == state["_prefix"]["command"]
 
     return Rule(_command)
 
diff --git a/tests/bot.py b/tests/bot.py
index 095e2eab..31ffb6c8 100644
--- a/tests/bot.py
+++ b/tests/bot.py
@@ -7,10 +7,22 @@ import sys
 sys.path.insert(0, os.path.abspath(".."))
 
 import nonebot
+from nonebot.log import logger, default_format
+
+# test custom log
+logger.add("error.log",
+           rotation="00:00",
+           diagnose=False,
+           level="ERROR",
+           format=default_format)
 
 nonebot.init()
 app = nonebot.get_asgi()
 
+# load builtin plugin
+nonebot.load_plugin("nonebot.plugins.base")
+
+# load local plugins
 nonebot.load_plugins("test_plugins")
 
 if __name__ == "__main__":
diff --git a/tests/test_plugins/test_package/test_command.py b/tests/test_plugins/test_package/test_command.py
index 8c811ddc..af060fff 100644
--- a/tests/test_plugins/test_package/test_command.py
+++ b/tests/test_plugins/test_package/test_command.py
@@ -11,7 +11,7 @@ test_command = on_command("帮助", to_me())
 
 @test_command.handle()
 async def test_handler(bot: Bot, event: Event, state: dict):
-    args = str(event.message)[len(list(state["_prefix"].keys())[0]):].strip()
+    args = str(event.message).strip()
     print("[!] Command:", state["_prefix"], "Args:", args)
     if args:
         state["help"] = args