diff --git a/python/mscclpp/language/channel.py b/python/mscclpp/language/channel.py
index 153985ff..cb68c80c 100644
--- a/python/mscclpp/language/channel.py
+++ b/python/mscclpp/language/channel.py
@@ -967,15 +967,19 @@ class SwitchChannel:
         chunk to the specified buffer region across all ranks in the rank group, with
         no explicit barrier required (the packet flag provides synchronization).
 
+        Both the source chunk and the destination buffer must be scratch buffers,
+        because the data is broadcast in LL (Low Latency) packet format (data + flag).
+
         Args:
             rank (int): The rank that will execute this broadcast operation.
-            src_chunk (Chunk): The source chunk containing packet data to broadcast.
-            buffer_offset (int): The offset in the destination buffer where data will be stored.
+            src_chunk (Chunk): The source scratch chunk containing packet data to broadcast.
+            buffer_offset (int): The offset in the destination scratch buffer where data will be stored.
             size (int): The size of data to broadcast.
             tb (int): The thread block ID that will execute this operation.
 
         Raises:
-            RuntimeError: If src_chunk rank is not in the rank group, if chunk size
+            RuntimeError: If src_chunk rank is not in the rank group, if the source
+                chunk or destination buffer is not a scratch buffer, if chunk size
                 doesn't match the required size, or if buffer size is insufficient.
 
         Example:
@@ -986,14 +990,15 @@ class SwitchChannel:
             raise RuntimeError(
                 f"Source chunk rank {src_chunk.rank} is not part of the rank group {self.rank_group.ranks}."
             )
+        if src_chunk.buffer != BufferType.scratch:
+            raise RuntimeError(f"Source chunk must be of type scratch for the packet broadcast.")
+        if self.buffer_type != BufferType.scratch:
+            raise RuntimeError(f"Destination buffer must be of type scratch for the packet broadcast.")
         if src_chunk.size != size:
             raise RuntimeError(f"Source chunk size {src_chunk.size} does not match the required size {size}.")
 
         for rank in self.rank_group.ranks:
-            if self.buffer_type == BufferType.scratch:
-                buffer_size = get_program().gpus[rank].scratch_chunks
-            else:
-                buffer_size = get_program().buffers[rank][self.buffer_type].size
+            buffer_size = get_program().gpus[rank].scratch_chunks
 
             if buffer_size < buffer_offset + size:
                 raise RuntimeError(