diff --git a/packages/server/src/bot/casual-brain.ts b/packages/server/src/bot/casual-brain.ts
index adcdb85..8a4ffa2 100644
--- a/packages/server/src/bot/casual-brain.ts
+++ b/packages/server/src/bot/casual-brain.ts
@@ -82,7 +82,11 @@ export class CasualBrain implements Brain {
     if (!destPiece) score += 50;
 
     const piece = view.pieces[move.from];
-    if (!piece) return score; // shouldn't happen, but safe.
+    // Reachable when scoring tests pass minimal fixture views. In real play
+    // the candidate's `from` is always one of our pieces (since candidates
+    // came from `legalCandidates` over our own squares), but the early
+    // return keeps unit tests from needing full board fixtures.
+    if (!piece) return score;
 
     const ownStartingRank = this.color === 'w' ? '1' : '8';
     const ownPawnStartingRank = this.color === 'w' ? '2' : '7';