diff --git a/src/simulator/crates/mc-mcts-service/src/protocol.rs b/src/simulator/crates/mc-mcts-service/src/protocol.rs
index 4a952763..bda6961a 100644
--- a/src/simulator/crates/mc-mcts-service/src/protocol.rs
+++ b/src/simulator/crates/mc-mcts-service/src/protocol.rs
@@ -18,9 +18,9 @@ pub struct MctsPlayerState {
     pub tech_index: u16,
     pub happiness_pool: i16,
     /// Relative military force vs each opponent slot (self-slot = 0).
-    pub force_rel: [u16; 4],
+    pub force_rel: [u16; 5],
     /// Diplomatic relation per opponent: <0 war, 0 peace, >0 friend.
-    pub relations: [i8; 4],
+    pub relations: [i8; 5],
     pub rng_state: u64,
     pub turn: u32,
 }
@@ -34,8 +34,8 @@ impl Default for MctsPlayerState {
             city_count: 0,
             tech_index: 0,
             happiness_pool: 0,
-            force_rel: [0; 4],
-            relations: [0; 4],
+            force_rel: [0; 5],
+            relations: [0; 5],
             rng_state: 0,
             turn: 0,
         }