diff --git a/dimos/protocol/pubsub/shmpubsub.py b/dimos/protocol/pubsub/shmpubsub.py
index 10f8763496..d0cfac01ff 100644
--- a/dimos/protocol/pubsub/shmpubsub.py
+++ b/dimos/protocol/pubsub/shmpubsub.py
@@ -26,7 +26,7 @@
 import time
 from collections import defaultdict
 from dataclasses import dataclass
-from typing import Any, Callable, Dict, Optional
+from typing import Any, Callable, Dict, Optional, Tuple
 
 import numpy as np
 
@@ -82,12 +82,13 @@ class _TopicState:
             "cp",
             "last_local_payload",
             "suppress_counts",
+            "message_counter",
         )
 
         def __init__(self, channel, capacity: int, cp_mod):
             self.channel = channel
             self.capacity = int(capacity)
-            self.shape = (self.capacity + 4,)  # +4 for uint32 length header
+            self.shape = (self.capacity + 12,)  # +12 for header: length(4) + pid(4) + counter(4)
             self.dtype = np.uint8
             self.subs: list[Callable[[bytes, str], None]] = []
             self.stop = threading.Event()
@@ -96,7 +97,8 @@ def __init__(self, channel, capacity: int, cp_mod):
             # TODO: implement an initializer variable for is_cuda once CUDA IPC is in
             self.cp = cp_mod
             self.last_local_payload: Optional[bytes] = None
-            self.suppress_counts = defaultdict(int)
+            self.suppress_counts: Dict[Tuple[int, int], int] = defaultdict(int)
+            self.message_counter = 0
 
     # ----- init / lifecycle -------------------------------------------------
 
@@ -158,9 +160,13 @@ def publish(self, topic: str, message: bytes) -> None:
             logger.error(f"Payload too large: {L} > capacity {st.capacity}")
             raise ValueError(f"Payload too large: {L} > capacity {st.capacity}")
 
-        # Mark this payload to suppress its single echo (handles back-to-back publishes)
-        payload_hash = hashlib.md5(payload_bytes).digest()
-        st.suppress_counts[payload_hash] += 1
+        # Create a unique identifier using PID and incrementing counter
+        pid = os.getpid()
+        st.message_counter += 1
+        message_id = (pid, st.message_counter)
+
+        # Mark this message to suppress its echo
+        st.suppress_counts[message_id] += 1
 
         # Synchronous local delivery first (zero extra copies)
         for cb in list(st.subs):
@@ -170,11 +176,14 @@ def publish(self, topic: str, message: bytes) -> None:
                 logger.warn(f"Payload couldn't be pushed to topic: {topic}")
                 pass
 
-        # Build host frame [len:4] + payload and publish
+        # Build host frame [len:4] + [pid:4] + [counter:4] + payload and publish
+        # We embed the message ID in the frame for echo suppression
         host = np.zeros(st.shape, dtype=st.dtype)
-        host[:4] = np.frombuffer(struct.pack("<I", L), dtype=np.uint8)
+        # Pack: length(4) + pid(4) + counter(4) + payload
+        header = struct.pack("<III", L + 8, pid, st.message_counter)  # L+8 for pid+counter
+        host[:12] = np.frombuffer(header, dtype=np.uint8)
         if L:
-            host[4 : 4 + L] = np.frombuffer(memoryview(payload_bytes), dtype=np.uint8)
+            host[12 : 12 + L] = np.frombuffer(memoryview(payload_bytes), dtype=np.uint8)
 
         st.channel.publish(host)
 
@@ -231,7 +240,7 @@ def reconfigure(self, topic: str, *, capacity: int) -> dict:
         """Change payload capacity (bytes) for a topic; returns new descriptor."""
         st = self._ensure_topic(topic)
         new_cap = int(capacity)
-        new_shape = (new_cap + 4,)
+        new_shape = (new_cap + 12,)  # +12 for header: length(4) + pid(4) + counter(4)
         desc = st.channel.reconfigure(new_shape, np.uint8)
         st.capacity = new_cap
         st.shape = new_shape
@@ -254,7 +263,7 @@ def _names_for_topic(topic: str, capacity: int) -> tuple[str, str]:
                 return f"psm_{h}_data", f"psm_{h}_ctrl"
 
             data_name, ctrl_name = _names_for_topic(topic, cap)
-            ch = CpuShmChannel((cap + 4,), np.uint8, data_name=data_name, ctrl_name=ctrl_name)
+            ch = CpuShmChannel((cap + 12,), np.uint8, data_name=data_name, ctrl_name=ctrl_name)
             st = SharedMemoryPubSubBase._TopicState(ch, cap, None)
             self._topics[topic] = st
             return st
@@ -270,20 +279,32 @@ def _fanout_loop(self, topic: str, st: _TopicState) -> None:
             host = np.array(view, copy=True)
 
             try:
-                L = struct.unpack("<I", host[:4].tobytes())[0]
-                if L == 0 or L < 0 or L > st.capacity:
+                # Read header: length(4) + pid(4) + counter(4)
+                header = struct.unpack("<III", host[:12].tobytes())
+                L = header[0]
+
+                if L < 8 or L > st.capacity + 8:
                     continue
 
-                payload = host[4 : 4 + L].tobytes()
+                # Extract PID and counter
+                pid = header[1]
+                counter = header[2]
+                message_id = (pid, counter)
+
+                # Extract actual payload (after removing the 8 bytes for pid+counter)
+                payload_len = L - 8
+                if payload_len > 0:
+                    payload = host[12 : 12 + payload_len].tobytes()
+                else:
+                    continue
 
                 # Drop exactly the number of local echoes we created
-                payload_hash = hashlib.md5(payload).digest()
-                cnt = st.suppress_counts.get(payload_hash, 0)
+                cnt = st.suppress_counts.get(message_id, 0)
                 if cnt > 0:
                     if cnt == 1:
-                        del st.suppress_counts[payload_hash]
+                        del st.suppress_counts[message_id]
                     else:
-                        st.suppress_counts[payload_hash] = cnt - 1
+                        st.suppress_counts[message_id] = cnt - 1
                     continue  # suppressed
 
             except Exception: