diff --git a/client/scripts/autoloads/sim_bridge.gd b/client/scripts/autoloads/sim_bridge.gd
index 0154ac915..aa3794948 100644
--- a/client/scripts/autoloads/sim_bridge.gd
+++ b/client/scripts/autoloads/sim_bridge.gd
@@ -75,9 +75,13 @@ func poll_snapshot() -> Variant:
 	return null
 
 # Called by transport layer (ticket #79) when raw bytes arrive from the server.
+# Latest-wins semantics: newer snapshots replace unconsumed ones. This is correct
+# for real-time rendering (stale frames are worthless). Upgrade to queue if needed.
 func receive_bytes(bytes: PackedByteArray) -> void:
 	var snapshot = Protocol.decode_snapshot(bytes)
 	if snapshot != null:
+		if _last_snapshot != null:
+			push_warning("SimBridge: overwriting unconsumed snapshot (tick %s replaced by %s)" % [_last_snapshot.tick, snapshot.tick])
 		_last_snapshot = snapshot
 
 # Drain the outbound buffer. Called by transport layer (ticket #79) to get encoded messages.
diff --git a/client/scripts/protocol/protocol.gd b/client/scripts/protocol/protocol.gd
index 8bfdfd8e2..be31cece7 100644
--- a/client/scripts/protocol/protocol.gd
+++ b/client/scripts/protocol/protocol.gd
@@ -26,17 +26,25 @@ static func decode_snapshot(bytes: PackedByteArray) -> Variant:
 		return null
 
 	var entities: Array[Dictionary] = []
-	for raw_entity in raw["entities"]:
+	var raw_entities: Array = raw["entities"]
+	var dropped := 0
+	for raw_entity in raw_entities:
 		var entity = _decode_entity(raw_entity)
 		if entity != null:
 			entities.append(entity)
+		else:
+			dropped += 1
+
+	if dropped > 0:
+		push_error("Protocol: %d/%d entities failed to decode (D-010 information boundary violation)" % [dropped, raw_entities.size()])
 
 	# GDScript int is signed 64-bit. Rust tick is u64 but will not exceed 2^63
-	# in any realistic scenario (would require ~29 billion years at 10 ticks/min).
+	# in any realistic scenario (would require ~29 billion years at 10 ticks/game-minute per D-031).
 	var tick: int = raw["tick"]
 	return {
 		"tick": tick,
 		"entities": entities,
+		"decode_errors": dropped,
 	}
 
 
diff --git a/client/tests/test_protocol.gd b/client/tests/test_protocol.gd
index 1a87fbe5c..e574bf318 100644
--- a/client/tests/test_protocol.gd
+++ b/client/tests/test_protocol.gd
@@ -164,7 +164,6 @@ func test_decode_player_input_empty_bytes() -> void:
 	assert_that(result).is_null()
 
 
-func test_encode_returns_empty_on_failure() -> void:
-	# Verify that a valid encode produces non-empty bytes
+func test_encode_produces_nonempty_bytes() -> void:
 	var bytes = Protocol.encode_player_input(1, "MoveNorth")
 	assert_that(bytes.size()).is_greater(0)