diff --git a/src/client/dev-dist/sw.js b/src/client/dev-dist/sw.js
index c0dee49..6ddc826 100644
--- a/src/client/dev-dist/sw.js
+++ b/src/client/dev-dist/sw.js
@@ -82,7 +82,7 @@ define(['./workbox-5a5d9309'], (function (workbox) { 'use strict';
     "revision": "3ca0b8505b4bec776b69afdba2768812"
   }, {
     "url": "index.html",
-    "revision": "0.vopjl6fp8f"
+    "revision": "0.inrr5fp7a9"
   }], {});
   workbox.cleanupOutdatedCaches();
   workbox.registerRoute(new workbox.NavigationRoute(workbox.createHandlerBoundToURL("index.html"), {
diff --git a/src/client/src/modules/game/GameView.tsx b/src/client/src/modules/game/GameView.tsx
index 045e792..a56ea14 100644
--- a/src/client/src/modules/game/GameView.tsx
+++ b/src/client/src/modules/game/GameView.tsx
@@ -706,6 +706,14 @@ export const GameView: React.FC<GameViewProps> = ({ gameState, currentPlayerId }
                               onDragStart={() => { }}
                               onClick={(id) => {
                                 if (gameState.step === 'declare_attackers') {
+                                  // Validate Creature Type
+                                  const types = card.types || [];
+                                  const typeLine = card.typeLine || '';
+                                  if (!types.includes('Creature') && !typeLine.includes('Creature')) {
+                                    // Optional: Shake effect or visual feedback that it's invalid
+                                    return;
+                                  }
+
                                   const newSet = new Set(proposedAttackers);
                                   if (newSet.has(id)) newSet.delete(id);
                                   else newSet.add(id);
diff --git a/src/server/game/RulesEngine.ts b/src/server/game/RulesEngine.ts
index 405ba35..1beaadd 100644
--- a/src/server/game/RulesEngine.ts
+++ b/src/server/game/RulesEngine.ts
@@ -471,14 +471,25 @@ export class RulesEngine {
     // 4. Combat Steps requiring declaration (Pause for External Action)
     if (step === 'declare_attackers') {
       // WAITING for declareAttackers() from Client
-      // Do NOT reset priority yet.
-      // TODO: Maybe set a timeout or auto-skip if no creatures?
+      // 508.1. Active Player gets priority to declare attackers.
+      // Unlike other steps where AP gets priority to cast spells, here the "Action" determines the flow.
+      // But technically, the AP *must* act. So we ensure they have priority.
+      if (this.state.priorityPlayerId !== activePlayerId) {
+        this.resetPriority(activePlayerId);
+      }
       return;
     }
 
     if (step === 'declare_blockers') {
       // WAITING for declareBlockers() from Client (Defending Player)
-      // Do NOT reset priority yet.
+      // 509.1. Defending Player gets priority to declare blockers.
+      // In 1v1, this is the non-active player.
+      const defendingPlayerId = this.state.turnOrder.find(id => id !== activePlayerId);
+      if (defendingPlayerId) {
+        if (this.state.priorityPlayerId !== defendingPlayerId) {
+          this.resetPriority(defendingPlayerId);
+        }
+      }
       return;
     }
 
diff --git a/src/server/managers/GameManager.ts b/src/server/managers/GameManager.ts
index 24c2c54..ce08809 100644
--- a/src/server/managers/GameManager.ts
+++ b/src/server/managers/GameManager.ts
@@ -110,7 +110,12 @@ export class GameManager {
           engine.castSpell(actorId, action.cardId, action.targets, action.position);
           break;
         case 'DECLARE_ATTACKERS':
-          engine.declareAttackers(actorId, action.attackers);
+          try {
+            engine.declareAttackers(actorId, action.attackers);
+          } catch (err: any) {
+            console.error(`[DeclareAttackers Error] Actor: ${actorId}, Active: ${game.activePlayerId}, Priority: ${game.priorityPlayerId}, Step: ${game.step}`);
+            throw err; // Re-throw to catch block below
+          }
           break;
         case 'DECLARE_BLOCKERS':
           engine.declareBlockers(actorId, action.blockers);