diff --git a/enjo_lib/comm/transport/datagrams.py b/enjo_lib/comm/transport/datagrams.py
index 800b96c..eba744e 100644
--- a/enjo_lib/comm/transport/datagrams.py
+++ b/enjo_lib/comm/transport/datagrams.py
@@ -7,6 +7,10 @@ from typing import (
     Literal,
 )
 
+from attrs import (
+    define,
+)
+
 from ...our_types import (
     EpochId,
     HumanFriendlyDesc,
@@ -14,11 +18,13 @@ from ...our_types import (
     JSON,
     ServiceType,
     ServiceClass,
-    serializable,
 )
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class GeneralTransportDatagram:
     _version: int = 1
     timestamp_ns: int
@@ -27,7 +33,10 @@ class GeneralTransportDatagram:
     data: JSON | GeneralTransportMetadata | None
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class GeneralTransportMetadata:
     pass
 
@@ -35,13 +44,19 @@ class GeneralTransportMetadata:
 # connect
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class ConnectDatagram(GeneralTransportDatagram):
     message_type: Literal["connect"] = "connect"
     data: ConnectMetadata
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class ConnectMetadata(GeneralTransportMetadata):
     epoch: EpochId
     type: ServiceType
@@ -51,13 +66,19 @@ class ConnectMetadata(GeneralTransportMetadata):
 # disconnect
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class DisconnectDatagram(GeneralTransportDatagram):
     message_type: Literal["disconnect"] = "disconnect"
     data: DisconnectMetadata
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class DisconnectMetadata(GeneralTransportMetadata):
     epoch: EpochId
     exceptional: bool
@@ -67,13 +88,19 @@ class DisconnectMetadata(GeneralTransportMetadata):
 # duplicate & replace sender types
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class DuplicateSenderDatagram(GeneralTransportDatagram):
     message_type: Literal["duplicate_sender"] = "duplicate_sender"
     data: ConnectMetadata
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class ReplaceSenderDatagram(GeneralTransportMetadata):
     message_type: Literal["replace_sender"] = "replace_sender"
     data: ConnectMetadata
@@ -82,13 +109,19 @@ class ReplaceSenderDatagram(GeneralTransportMetadata):
 # failure
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class FailureDatagram(GeneralTransportDatagram):
     message_type: Literal["failure"] = "failure"
     data: FailureMetadata
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class FailureMetadata(GeneralTransportMetadata):
     """
     Issues that a specific service has failed.
@@ -105,7 +138,10 @@ class FailureMetadata(GeneralTransportMetadata):
 # restart
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class RestartDatagram(GeneralTransportDatagram):
     """issues a restart of a whole Enjo network"""
 
@@ -116,7 +152,10 @@ class RestartDatagram(GeneralTransportDatagram):
 # transmit
 
 
-@serializable
+@define(
+    frozen=True,
+    kw_only=True,
+)
 class TransmitDatagram(GeneralTransportDatagram):
     message_type: Literal["transmit"] = "transmit"
     data: JSON
diff --git a/enjo_lib/our_types.py b/enjo_lib/our_types.py
index fd5bc8b..8c60a97 100644
--- a/enjo_lib/our_types.py
+++ b/enjo_lib/our_types.py
@@ -7,9 +7,6 @@ from collections.abc import (
 from decimal import (
     Decimal,
 )
-from functools import (
-    partial,
-)
 from typing import (
     TypeAlias,
     NewType,
@@ -19,10 +16,6 @@ from uuid import (
     UUID,
 )
 
-from attrs import (
-    define,
-)
-
 
 JSON: TypeAlias = Union[
     Mapping[str, "JSON"],
@@ -34,13 +27,6 @@ JSON: TypeAlias = Union[
 ]
 
 
-serializable = partial(
-    define,
-    frozen=True,
-    kw_only=True,
-)
-
-
 ReverseDomainArg = NewType("ReverseDomainArg", str)
 """e.g. `"de.6nw.enjo.controller"`"""