diff --git a/cocoscreator_projects/YouleNexus/assets/framework/protocol/active-game.ts b/cocoscreator_projects/YouleNexus/assets/framework/protocol/active-game.ts
new file mode 100644
index 0000000..dbd5e5f
--- /dev/null
+++ b/cocoscreator_projects/YouleNexus/assets/framework/protocol/active-game.ts
@@ -0,0 +1,17 @@
+import type { IGameModule } from '../sdk/index.ts';
+
+/**
+ * 当前激活的子游戏槽（= 旧 Game_Modify 的运行时角色）。
+ *
+ * 框架在进房时 setGame()，离房时 clear()。Router 据此分发对局 route 的包。
+ * 单例设计：同一时刻只允许一个子游戏激活（与旧 12_Logic 一致）。
+ */
+export class ActiveGame {
+  private game: IGameModule | null = null;
+
+  get(): IGameModule | null { return this.game; }
+
+  set(game: IGameModule): void { this.game = game; }
+
+  clear(): void { this.game = null; }
+}
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diff --git a/cocoscreator_projects/YouleNexus/assets/framework/protocol/router.ts b/cocoscreator_projects/YouleNexus/assets/framework/protocol/router.ts
new file mode 100644
index 0000000..4ddbc62
--- /dev/null
+++ b/cocoscreator_projects/YouleNexus/assets/framework/protocol/router.ts
@@ -0,0 +1,53 @@
+import type { InboundMessage } from '../core/types/envelope.ts';
+import { Route } from '../core/constants.ts';
+import type { ActiveGame } from './active-game.ts';
+
+/** 平台层 handler 表：key = rpc 字符串（与协议逐字对齐）。 */
+export type PlatformHandlers = Record<string, (data: unknown) => void>;
+
+/**
+ * Router：收包路由分界（C §4.1 的红线）。
+ *
+ * 分发规则：
+ * - route ∈ {platform, agent, room} → 平台 handlers（RpcList 覆盖的包）
+ * - route = <game route>（= activeGame.route）→ activeGame.onReceive
+ * - 其他或未注册：显式抛错（第二准则：不静默吞包）
+ *
+ * 不持有状态——只做消息分发。状态由 PlatformSession/子游戏维护。
+ */
+export class Router {
+  constructor(
+    private readonly opts: {
+      activeGame: ActiveGame;
+      platformHandlers: PlatformHandlers;
+    },
+  ) {}
+
+  dispatch(msg: InboundMessage): void {
+    const { route, rpc, data } = msg;
+    // 平台三层 route：platform/agent/room 全部走平台 handlers
+    if (route === Route.platform || route === Route.agent || route === Route.room) {
+      const handler = this.opts.platformHandlers[rpc];
+      if (!handler) {
+        throw new Error(
+          `Router 收到未注册的平台 rpc: route=${route} rpc=${rpc}（platformHandlers 未注册,第二准则禁止兜底）`,
+        );
+      }
+      handler(data);
+      return;
+    }
+    // 对局 route：必须与 activeGame.route 严格匹配
+    const game = this.opts.activeGame.get();
+    if (!game) {
+      throw new Error(
+        `Router 收到对局包但无激活子游戏: route=${route} rpc=${rpc}（未进房或子游戏未注册）`,
+      );
+    }
+    if (game.route !== route) {
+      throw new Error(
+        `Router route 与 activeGame.route 不匹配: msg.route=${route} activeGame.route=${game.route}`,
+      );
+    }
+    game.onReceive(rpc, data);
+  }
+}
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diff --git a/cocoscreator_projects/framework-tests/protocol/active-game.test.ts b/cocoscreator_projects/framework-tests/protocol/active-game.test.ts
new file mode 100644
index 0000000..0886bb8
--- /dev/null
+++ b/cocoscreator_projects/framework-tests/protocol/active-game.test.ts
@@ -0,0 +1,40 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { ActiveGame } from '../../YouleNexus/assets/framework/protocol/active-game.ts';
+import type { IGameModule, GameContext } from '../../YouleNexus/assets/framework/sdk/index.ts';
+
+class MockGame implements IGameModule {
+  readonly route = 'mock';
+  events: string[] = [];
+  onEnter(_ctx: GameContext): void { this.events.push('onEnter'); }
+  onExit(): void { this.events.push('onExit'); }
+  onReceive(rpc: string, _d: unknown): void { this.events.push(`onReceive:${rpc}`); }
+  onReconnect(_d: unknown): void { this.events.push('onReconnect'); }
+}
+
+test('初始: getGame 返回 null', () => {
+  assert.equal(new ActiveGame().get(), null);
+});
+
+test('setGame: 设置后 get 返回同一实例', () => {
+  const slot = new ActiveGame();
+  const g = new MockGame();
+  slot.set(g);
+  assert.equal(slot.get(), g);
+});
+
+test('clear: 清空后 get 返回 null', () => {
+  const slot = new ActiveGame();
+  slot.set(new MockGame());
+  slot.clear();
+  assert.equal(slot.get(), null);
+});
+
+test('set 覆盖前一个 game', () => {
+  const slot = new ActiveGame();
+  const g1 = new MockGame();
+  const g2 = new MockGame();
+  slot.set(g1);
+  slot.set(g2);
+  assert.equal(slot.get(), g2);
+});
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diff --git a/cocoscreator_projects/framework-tests/protocol/router.test.ts b/cocoscreator_projects/framework-tests/protocol/router.test.ts
new file mode 100644
index 0000000..7c494b1
--- /dev/null
+++ b/cocoscreator_projects/framework-tests/protocol/router.test.ts
@@ -0,0 +1,75 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { Router } from '../../YouleNexus/assets/framework/protocol/router.ts';
+import { ActiveGame } from '../../YouleNexus/assets/framework/protocol/active-game.ts';
+import type { InboundMessage } from '../../YouleNexus/assets/framework/core/types/envelope.ts';
+import type { IGameModule, GameContext } from '../../YouleNexus/assets/framework/sdk/index.ts';
+
+class MockGame implements IGameModule {
+  readonly route = 'mock';
+  events: string[] = [];
+  onEnter(_ctx: GameContext): void {}
+  onExit(): void {}
+  onReceive(rpc: string, _d: unknown): void { this.events.push(`onReceive:${rpc}`); }
+  onReconnect(_d: unknown): void {}
+}
+
+const msg = (route: string, rpc: string, data: unknown = {}): InboundMessage =>
+  ({ route, rpc, data } as InboundMessage);
+
+test('platform route → 平台 handler(已注册)', () => {
+  const slot = new ActiveGame();
+  const calls: Array<[string, unknown]> = [];
+  const router = new Router({
+    activeGame: slot,
+    platformHandlers: { player_login: (d) => calls.push(['player_login', d]) },
+  });
+  router.dispatch(msg('agent', 'player_login', { state: 0 }));
+  assert.equal(calls.length, 1);
+  assert.equal(calls[0][0], 'player_login');
+});
+
+test('platform route → 平台 handler 未注册 → 显式抛错(第二准则)', () => {
+  const slot = new ActiveGame();
+  const router = new Router({ activeGame: slot, platformHandlers: {} });
+  assert.throws(() => router.dispatch(msg('agent', 'unknown_rpc')), /unknown_rpc/);
+});
+
+test('非 platform route 但 activeGame 已注册 → onReceive', () => {
+  const slot = new ActiveGame();
+  const game = new MockGame();
+  slot.set(game);
+  const router = new Router({ activeGame: slot, platformHandlers: {} });
+  router.dispatch(msg('mock', 'deal_card', { n: 1 }));
+  assert.deepEqual(game.events, ['onReceive:deal_card']);
+});
+
+test('非 platform route 但 activeGame 未注册 → 显式抛错', () => {
+  const slot = new ActiveGame();
+  const router = new Router({ activeGame: slot, platformHandlers: {} });
+  assert.throws(() => router.dispatch(msg('mock', 'deal_card')), /mock.*deal_card/);
+});
+
+test('route 与 activeGame.route 不匹配 → 显式抛错', () => {
+  const slot = new ActiveGame();
+  slot.set(new MockGame()); // route = 'mock'
+  const router = new Router({ activeGame: slot, platformHandlers: {} });
+  assert.throws(() => router.dispatch(msg('other-game', 'rpc')), /other-game/);
+});
+
+test('platform/agent/room 三 route 全部走平台 handler(对称)', () => {
+  const slot = new ActiveGame();
+  const calls: string[] = [];
+  const router = new Router({
+    activeGame: slot,
+    platformHandlers: {
+      r1: () => calls.push('r1'),
+      r2: () => calls.push('r2'),
+      r3: () => calls.push('r3'),
+    },
+  });
+  router.dispatch(msg('platform', 'r1'));
+  router.dispatch(msg('agent', 'r2'));
+  router.dispatch(msg('room', 'r3'));
+  assert.deepEqual(calls, ['r1', 'r2', 'r3']);
+});
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