diff --git a/astrbot/core/star/filter/command.py b/astrbot/core/star/filter/command.py
index 31949b674c..93c7c6a202 100755
--- a/astrbot/core/star/filter/command.py
+++ b/astrbot/core/star/filter/command.py
@@ -198,10 +198,18 @@ def filter(self, event: AstrMessageEvent, cfg: AstrBotConfig) -> bool:
         # 检查是否以指令开头
         message_str = re.sub(r"\s+", " ", event.get_message_str().strip())
         ok = False
-        for full_cmd in self.get_complete_command_names():
+        # Try the longest name first so that when several complete command names
+        # share a prefix (e.g. an alias "show" and "show all"), the most specific
+        # one wins and the match is stable. get_complete_command_names() is built
+        # from a set, so its own order is not deterministic; sort here rather than
+        # there because other callers rely on [0] being the primary command name.
+        for full_cmd in sorted(
+            self.get_complete_command_names(), key=lambda name: (-len(name), name)
+        ):
             if message_str.startswith(f"{full_cmd} ") or message_str == full_cmd:
                 ok = True
                 message_str = message_str[len(full_cmd) :].strip()
+                break
         if not ok:
             return False
 
diff --git a/tests/test_command_filter.py b/tests/test_command_filter.py
new file mode 100644
index 0000000000..a1db14b8ae
--- /dev/null
+++ b/tests/test_command_filter.py
@@ -0,0 +1,48 @@
+from types import SimpleNamespace
+
+from astrbot.core.star.filter.command import CommandFilter, GreedyStr
+
+
+def _run_filter(command_name: str, alias: set, message: str):
+    cmd_filter = CommandFilter(command_name=command_name, alias=set(alias))
+    # A single greedy parameter captures everything after the command name.
+    cmd_filter.handler_params = {"query": GreedyStr}
+    extras: dict = {}
+    event = SimpleNamespace(
+        is_at_or_wake_command=True,
+        get_message_str=lambda: message,
+        set_extra=lambda key, value: extras.__setitem__(key, value),
+    )
+    ok = cmd_filter.filter(event, None)
+    return ok, extras.get("parsed_params")
+
+
+def test_command_filter_keeps_argument_matching_an_alias():
+    # Invoking a command by one name with a first argument that happens to equal
+    # another alias of the same command must not strip that argument a second time.
+    ok, params = _run_filter("search", {"find"}, "search find keyword")
+    assert ok
+    assert params == {"query": "find keyword"}
+
+
+def test_command_filter_keeps_sole_argument_matching_an_alias():
+    ok, params = _run_filter("add", {"new"}, "add new")
+    assert ok
+    assert params == {"query": "new"}
+
+
+def test_command_filter_normal_argument_unaffected():
+    ok, params = _run_filter("search", {"find"}, "search cat photo")
+    assert ok
+    assert params == {"query": "cat photo"}
+
+
+def test_command_filter_prefers_longest_overlapping_command_name():
+    # When a command name and one of its aliases share a prefix ("show" vs
+    # "show all"), the most specific one must win regardless of the set's
+    # iteration order, so only the longer name is stripped and the rest is the
+    # argument. Without the longest-first ordering, "show" would match first and
+    # leak "all" into the argument.
+    ok, params = _run_filter("show", {"show all"}, "show all photos")
+    assert ok
+    assert params == {"query": "photos"}