diff --git a/crates/rrt-runtime/src/smp.rs b/crates/rrt-runtime/src/smp.rs
index cb01008..c75298b 100644
--- a/crates/rrt-runtime/src/smp.rs
+++ b/crates/rrt-runtime/src/smp.rs
@@ -10899,6 +10899,16 @@ fn parse_real_grouped_effect_row_summary(
             ));
         }
     }
+    if descriptor_metadata.is_some_and(|metadata| metadata.parameter_family == "world_building_spawn")
+    {
+        let candidate_id = descriptor_id.saturating_sub(503);
+        notes.push(format!(
+            "add-building descriptor maps to live candidate id {candidate_id}"
+        ));
+        notes.push(
+            "0x430270 add-building consumer uses placement count byte 0x11 plus packed span words 0x14/0x16 after the descriptor_id - 503 candidate bridge; it does not branch directly on grouped opcode".to_string(),
+        );
+    }
 
     Some(SmpLoadedPackedEventGroupedEffectRowSummary {
         group_index,