diff --git a/app/game-engine/package.json b/app/game-engine/package.json
index 6e9e683b..0ec6d95b 100644
--- a/app/game-engine/package.json
+++ b/app/game-engine/package.json
@@ -5,9 +5,95 @@
     "type": "module",
     "main": "dist/index.js",
     "types": "dist/index.d.ts",
+    "exports": {
+        ".": {
+            "types": "./dist/index.d.ts",
+            "default": "./dist/index.js"
+        },
+        "./auction/finalizer.js": {
+            "types": "./dist/auction/finalizer.d.ts",
+            "default": "./dist/auction/finalizer.js"
+        },
+        "./scenario/mapLoader.js": {
+            "types": "./dist/scenario/mapLoader.d.ts",
+            "default": "./dist/scenario/mapLoader.js"
+        },
+        "./scenario/scenarioComposition.js": {
+            "types": "./dist/scenario/scenarioComposition.d.ts",
+            "default": "./dist/scenario/scenarioComposition.js"
+        },
+        "./scenario/scenarioLoader.js": {
+            "types": "./dist/scenario/scenarioLoader.d.ts",
+            "default": "./dist/scenario/scenarioLoader.js"
+        },
+        "./scenario/scenarioSeeder.js": {
+            "types": "./dist/scenario/scenarioSeeder.d.ts",
+            "default": "./dist/scenario/scenarioSeeder.js"
+        },
+        "./scenario/unitSetLoader.js": {
+            "types": "./dist/scenario/unitSetLoader.d.ts",
+            "default": "./dist/scenario/unitSetLoader.js"
+        },
+        "./turn/databaseHooks.js": {
+            "types": "./dist/turn/databaseHooks.d.ts",
+            "default": "./dist/turn/databaseHooks.js"
+        },
+        "./turn/inMemoryWorld.js": {
+            "types": "./dist/turn/inMemoryWorld.d.ts",
+            "default": "./dist/turn/inMemoryWorld.js"
+        },
+        "./turn/monthlyDisasterAction.js": {
+            "types": "./dist/turn/monthlyDisasterAction.d.ts",
+            "default": "./dist/turn/monthlyDisasterAction.js"
+        },
+        "./turn/monthlyEventHandler.js": {
+            "types": "./dist/turn/monthlyEventHandler.d.ts",
+            "default": "./dist/turn/monthlyEventHandler.js"
+        },
+        "./turn/monthlyNationBettingAction.js": {
+            "types": "./dist/turn/monthlyNationBettingAction.d.ts",
+            "default": "./dist/turn/monthlyNationBettingAction.js"
+        },
+        "./turn/npcPossessionService.js": {
+            "types": "./dist/turn/npcPossessionService.d.ts",
+            "default": "./dist/turn/npcPossessionService.js"
+        },
+        "./turn/rankData.js": {
+            "types": "./dist/turn/rankData.d.ts",
+            "default": "./dist/turn/rankData.js"
+        },
+        "./turn/reservedTurnHandler.js": {
+            "types": "./dist/turn/reservedTurnHandler.d.ts",
+            "default": "./dist/turn/reservedTurnHandler.js"
+        },
+        "./turn/reservedTurnStore.js": {
+            "types": "./dist/turn/reservedTurnStore.d.ts",
+            "default": "./dist/turn/reservedTurnStore.js"
+        },
+        "./turn/selectPoolService.js": {
+            "types": "./dist/turn/selectPoolService.d.ts",
+            "default": "./dist/turn/selectPoolService.js"
+        },
+        "./turn/turnCommandProfile.js": {
+            "types": "./dist/turn/turnCommandProfile.d.ts",
+            "default": "./dist/turn/turnCommandProfile.js"
+        },
+        "./turn/types.js": {
+            "types": "./dist/turn/types.d.ts",
+            "default": "./dist/turn/types.js"
+        },
+        "./turn/worldCommandHandler.js": {
+            "types": "./dist/turn/worldCommandHandler.d.ts",
+            "default": "./dist/turn/worldCommandHandler.js"
+        },
+        "./turn/worldLoader.js": {
+            "types": "./dist/turn/worldLoader.d.ts",
+            "default": "./dist/turn/worldLoader.js"
+        }
+    },
     "scripts": {
-        "build": "tsdown -c ../../tsdown.config.ts -F @sammo-ts/game-engine",
-        "dev": "tsdown -c ../../tsdown.config.ts -F @sammo-ts/game-engine --watch",
+        "build": "tsdown -c ./tsdown.config.ts && node ../../tools/check-package-exports.mjs .",
+        "dev": "tsdown -c ./tsdown.config.ts --watch",
         "start": "pnpm run build && GAME_ENGINE_ROLE=turn-daemon node dist/index.js",
         "lint": "eslint .",
         "lint:fix": "eslint . --fix",
diff --git a/app/game-engine/tsdown.config.ts b/app/game-engine/tsdown.config.ts
new file mode 100644
index 00000000..6e0af083
--- /dev/null
+++ b/app/game-engine/tsdown.config.ts
@@ -0,0 +1,37 @@
+import { defineConfig } from 'tsdown';
+
+export default defineConfig({
+    entry: {
+        index: 'src/index.ts',
+        'auction/finalizer': 'src/auction/finalizer.ts',
+        'scenario/mapLoader': 'src/scenario/mapLoader.ts',
+        'scenario/scenarioComposition': 'src/scenario/scenarioComposition.ts',
+        'scenario/scenarioLoader': 'src/scenario/scenarioLoader.ts',
+        'scenario/scenarioSeeder': 'src/scenario/scenarioSeeder.ts',
+        'scenario/unitSetLoader': 'src/scenario/unitSetLoader.ts',
+        'turn/databaseHooks': 'src/turn/databaseHooks.ts',
+        'turn/inMemoryWorld': 'src/turn/inMemoryWorld.ts',
+        'turn/monthlyDisasterAction': 'src/turn/monthlyDisasterAction.ts',
+        'turn/monthlyEventHandler': 'src/turn/monthlyEventHandler.ts',
+        'turn/monthlyNationBettingAction': 'src/turn/monthlyNationBettingAction.ts',
+        'turn/npcPossessionService': 'src/turn/npcPossessionService.ts',
+        'turn/rankData': 'src/turn/rankData.ts',
+        'turn/reservedTurnHandler': 'src/turn/reservedTurnHandler.ts',
+        'turn/reservedTurnStore': 'src/turn/reservedTurnStore.ts',
+        'turn/selectPoolService': 'src/turn/selectPoolService.ts',
+        'turn/turnCommandProfile': 'src/turn/turnCommandProfile.ts',
+        'turn/types': 'src/turn/types.ts',
+        'turn/worldCommandHandler': 'src/turn/worldCommandHandler.ts',
+        'turn/worldLoader': 'src/turn/worldLoader.ts',
+    },
+    format: 'es',
+    outDir: 'dist',
+    dts: {
+        build: true,
+    },
+    sourcemap: true,
+    target: 'node22',
+    platform: 'node',
+    fixedExtension: false,
+    hash: false,
+});
diff --git a/docs/architecture/package-boundaries.md b/docs/architecture/package-boundaries.md
index ccaebfb4..57d16482 100644
--- a/docs/architecture/package-boundaries.md
+++ b/docs/architecture/package-boundaries.md
@@ -40,6 +40,12 @@ Resource를 읽는 `scenarioLoader`, `mapLoader`, `unitSetLoader`,
 사용합니다. `@sammo-ts/game-engine` 루트는 daemon process entrypoint이므로
 API 제품 소스에서 library처럼 import하지 않습니다.
 
+game-engine의 공개 subpath는 `app/game-engine/package.json`의 `exports`와
+`app/game-engine/tsdown.config.ts`의 entry에 함께 선언합니다. `pnpm --filter
+@sammo-ts/game-engine build`는 각 JS·type export target이 실제 생성됐는지
+검사하므로, typecheck에서는 보이지만 production Node에서만 실패하는 subpath
+누락을 배포 전에 차단합니다.
+
 Frontend가 tRPC router shape를 참조할 때는 `import type`만 사용하고 backend
 package를 `devDependencies`에 둡니다. 브라우저에서 실제 실행하는 공유 값만
 `common` 또는 `logic`의 browser-safe export에서 가져옵니다.
diff --git a/tools/check-package-exports.mjs b/tools/check-package-exports.mjs
new file mode 100644
index 00000000..484ce864
--- /dev/null
+++ b/tools/check-package-exports.mjs
@@ -0,0 +1,31 @@
+import { access, readFile } from 'node:fs/promises';
+import path from 'node:path';
+
+const packageRoot = path.resolve(process.argv[2] ?? '');
+if (!process.argv[2]) {
+    throw new Error('Usage: node tools/check-package-exports.mjs <package-directory>');
+}
+
+const manifest = JSON.parse(await readFile(path.join(packageRoot, 'package.json'), 'utf8'));
+const targets = new Set();
+for (const descriptor of Object.values(manifest.exports ?? {})) {
+    if (typeof descriptor === 'string') {
+        targets.add(descriptor);
+        continue;
+    }
+    if (descriptor && typeof descriptor === 'object') {
+        for (const target of Object.values(descriptor)) {
+            if (typeof target === 'string') targets.add(target);
+        }
+    }
+}
+
+for (const target of targets) {
+    const absolute = path.resolve(packageRoot, target);
+    if (absolute !== packageRoot && !absolute.startsWith(`${packageRoot}${path.sep}`)) {
+        throw new Error(`Package export escapes its package directory: ${target}`);
+    }
+    await access(absolute);
+}
+
+process.stdout.write(`Validated ${targets.size} package export targets for ${manifest.name}.\n`);