diff --git a/python/sglang/srt/managers/io_struct.py b/python/sglang/srt/managers/io_struct.py
index 941b5a19d..b30c9216f 100644
--- a/python/sglang/srt/managers/io_struct.py
+++ b/python/sglang/srt/managers/io_struct.py
@@ -1346,6 +1346,7 @@ class ExpertDistributionReqType(Enum):
     DUMP_RECORD = 3
 
 
+@dataclass
 class ExpertDistributionReq(BaseReq):
     action: ExpertDistributionReqType