diff --git a/src/core_modules/command_spec.py b/src/core_modules/command_spec.py
new file mode 100644
index 00000000..fbf5aa7e
--- /dev/null
+++ b/src/core_modules/command_spec.py
@@ -0,0 +1,73 @@
+from src import ModuleManager, utils
+
+class Module(ModuleManager.BaseModule):
+    def _spec_chunk(self, server, channel, types, args):
+        options = []
+        first_error = None
+        for type in types:
+            chunk = None
+            n = 0
+            error = None
+
+            if type == "time" and args:
+                time, _ = utils.parse.timed_args(args)
+                chunk = time
+                n = 1
+                error = "Invalid timeframe"
+            elif type == "channel" and args:
+                if args[0] in server.channels:
+                    chunk = server.channels.get(args[0])
+                n = 1
+                error = "No such channel"
+            elif type == "cuser" and args:
+                user = server.get_user(args[0], create=False)
+                if user and channel.has_user(user):
+                    chunk = user
+                n = 1
+                error = "That user is not in this channel"
+            elif type == "user" and args:
+                chunk = server.get_user(args[0], create=False)
+                n = 1
+                error = "No such user"
+            elif type == "word" and args:
+                chunk = args[0]
+                n = 1
+            elif type == "...":
+                chunk = " ".join(args)
+                n = len(args)
+
+            options.append([type, chunk, n, error])
+        return options
+
+    @utils.hook("preprocess.command")
+    def preprocess(self, event):
+        spec = event["hook"].get_kwarg("spec", None)
+        if not spec == None:
+            server = event["server"]
+            channel = event["target"] if event["is_channel"] else None
+            args = event["args_split"].copy()
+
+            out = []
+            for word in spec.split():
+                types = word[1:].split("|")
+                optional = word[0] == "?"
+
+                options = self._spec_chunk(server, channel, types, args)
+
+                found = False
+                first_error = None
+                for type, chunk, n, error in options:
+                    if error and not first_error:
+                        first_error = error
+
+                    if chunk:
+                        found = True
+                        args = args[n:]
+                        if len(types) > 1:
+                            chunk = [type, chunk]
+                        out.append(chunk)
+
+                if not optional and not found:
+                    error = first_error or "Invalid arguments"
+                    return utils.consts.PERMISSION_HARD_FAIL, error
+            event["kwargs"]["spec"] = out
diff --git a/src/core_modules/commands/__init__.py b/src/core_modules/commands/__init__.py
index b22541d5..5a312bda 100644
--- a/src/core_modules/commands/__init__.py
+++ b/src/core_modules/commands/__init__.py
@@ -184,7 +184,8 @@ class Module(ModuleManager.BaseModule):
             "target": target, "target_str": target_str,
             "is_channel": is_channel, "line": line, "args_split": args_split,
             "command": command, "args": " ".join(args_split), "stdout": stdout,
-            "stderr": stderr, "tags": {}}
+            "stderr": stderr, "tags": {}, "kwargs": {}}
+
         event_kwargs.update(kwargs)
 
         check_assert = lambda check: self._check_assert(event_kwargs, user,
@@ -195,6 +196,7 @@ class Module(ModuleManager.BaseModule):
 
         check_success, check_message = self._check("preprocess", event_kwargs)
         if check_success:
+            event_kwargs.update(event_kwargs.pop("kwargs"))
             new_event = self.events.on(hook.event_name).make_event(**event_kwargs)
             self.log.trace("calling command '%s': %s", [command, new_event.kwargs])