diff --git a/piker/data/_sharedmem.py b/piker/data/_sharedmem.py
index b4e6de86..aa2a5320 100644
--- a/piker/data/_sharedmem.py
+++ b/piker/data/_sharedmem.py
@@ -97,8 +97,7 @@ class _Token:
 
     def __post_init__(self):
         # np.array requires a list for dtype
-        self.dtype_descr = np.dtype(
-            list(self.dtype_descr)).descr
+        self.dtype_descr = np.dtype(list(map(tuple, self.dtype_descr))).descr
 
     def as_msg(self):
         return asdict(self)
diff --git a/piker/data/feed.py b/piker/data/feed.py
index 0f856627..4a41500d 100644
--- a/piker/data/feed.py
+++ b/piker/data/feed.py
@@ -514,7 +514,10 @@ async def open_feed(
 
                 # cast shm dtype to list... can't member why we need this
                 shm_token = data['shm_token']
-                shm_token['dtype_descr'] = list(shm_token['dtype_descr'])
+
+                # XXX: msgspec won't relay through the tuples XD
+                shm_token['dtype_descr'] = list(map(tuple, shm_token['dtype_descr']))
+
                 assert shm_token == shm.token  # sanity
 
             feed._max_sample_rate = max(ohlc_sample_rates)