diff --git a/scripts/check-game-distribution-media-e2e.mjs b/scripts/check-game-distribution-media-e2e.mjs
index 85c4486d2..545e1aa6c 100644
--- a/scripts/check-game-distribution-media-e2e.mjs
+++ b/scripts/check-game-distribution-media-e2e.mjs
@@ -15,6 +15,12 @@ import { readFile } from 'node:fs/promises';
 
 import JSZip from 'jszip';
 
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:12401';
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
 const ADMIN_USER = (process.env.E2E_ADMIN_USER ?? '').trim();
@@ -26,10 +32,6 @@ if (!ADMIN_USER || !ADMIN_PASSWORD) {
   );
   process.exit(2);
 }
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
 
 let failures = 0;
 function check(name, ok, detail = '') {
@@ -71,20 +73,16 @@ async function api(path, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${path}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -106,47 +104,6 @@ function stamp() {
   return `${Date.now()}${Math.floor(Math.random() * 1000)}`;
 }
 
-/**
- * 发布用图片 part。
- *
- * 新合同不再走素材库直传登记：图片字节随 `cover` / `screenshot` part 提交，由服务端直写
- * 项目快照桶并派生 objectKey。这里只在本机准备字节、文件名与 content-type。
- */
-function imagePart(kind, id, bytes = COVER_PNG) {
-  return {
-    bytes,
-    fileName: `${kind}-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/**
- * 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 按顺序重复的 `screenshot` 二进制 part。
- *
- * `metadata.screenshots` 里的 `null` 槽位按出现顺序消费 `screenshots` 数组里的 part；string
- * 槽位沿用该 objectKey。调用方负责保证 null 槽位数量与 part 数量一致（不一致服务端会 400）。
- */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
-
 function gameMetadata(overrides = {}) {
   return {
     title: `分发媒体验证 ${stamp().slice(-6)}`,
diff --git a/scripts/check-game-distribution-ops-rollback-e2e.mjs b/scripts/check-game-distribution-ops-rollback-e2e.mjs
index a4cce4571..78cf19e00 100644
--- a/scripts/check-game-distribution-ops-rollback-e2e.mjs
+++ b/scripts/check-game-distribution-ops-rollback-e2e.mjs
@@ -23,10 +23,12 @@ import path from 'node:path';
 
 import JSZip from 'jszip';
 
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:8082';
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
 const ADMIN_USER = (process.env.E2E_ADMIN_USER ?? '').trim();
@@ -71,20 +73,16 @@ async function api(pathname, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${pathname}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -172,36 +170,8 @@ async function setPublishGate(admin, enabled, rolloutPercent) {
   return response;
 }
 
-/** 发布用封面图片 part：字节随 `cover` part 提交，服务端直写项目快照桶。 */
-function coverImagePart(id) {
-  return {
-    bytes: COVER_PNG,
-    fileName: `ops-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/** 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 重复 `screenshot` 二进制 part。 */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
+const coverImagePart = (id) =>
+  imagePart('cover', id, { fileName: `ops-${id}.png` });
 
 function gameMetadata(title, coverObjectKey) {
   return {
diff --git a/scripts/check-game-distribution-owner-isolation.mjs b/scripts/check-game-distribution-owner-isolation.mjs
index cf7594c41..a7f026883 100644
--- a/scripts/check-game-distribution-owner-isolation.mjs
+++ b/scripts/check-game-distribution-owner-isolation.mjs
@@ -11,10 +11,12 @@
 // 的 my-games）→ 作者撤回自己的版本成功。整条链路只在本机 dev 数据库落行；唯一的存储写入
 // 是「建游戏必须提供封面」逼出的一个 67 字节 PNG（新合同由服务端把 cover part 直写项目
 // 快照桶），发行包分片与确认全部停在越权拒绝之前，不会产生任何对象。
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:4198';
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
 const ADMIN_USER = (process.env.E2E_ADMIN_USER ?? '').trim();
@@ -49,20 +51,16 @@ async function api(path, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${path}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -95,41 +93,8 @@ function gameMetadata(title) {
   };
 }
 
-/**
- * 发布用封面图片 part。
- *
- * 新合同不再走素材库直传登记：封面字节随创建请求的 `cover` part 提交，由服务端直写项目
- * 快照桶。这里只在本机准备字节、文件名与 content-type。
- */
-function coverImagePart(id) {
-  return {
-    bytes: COVER_PNG,
-    fileName: `owner-isolation-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/** 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 重复 `screenshot` 二进制 part。 */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
+const coverImagePart = (id) =>
+  imagePart('cover', id, { fileName: `owner-isolation-${id}.png` });
 
 async function register(prefix) {
   const response = await api('/api/auth/entry', {
diff --git a/scripts/check-game-distribution-package-limits-e2e.mjs b/scripts/check-game-distribution-package-limits-e2e.mjs
index 5c5c7a5f1..c6a02dd94 100644
--- a/scripts/check-game-distribution-package-limits-e2e.mjs
+++ b/scripts/check-game-distribution-package-limits-e2e.mjs
@@ -9,10 +9,12 @@ import { createHash, randomBytes } from 'node:crypto';
 
 import JSZip from 'jszip';
 
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:8082';
 const API_PORT = Number(new URL(API).port || '80');
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
@@ -45,20 +47,16 @@ async function api(pathname, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${pathname}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -90,36 +88,8 @@ function apiServerWorkingSetMb() {
   }
 }
 
-/** 发布用封面图片 part：字节随 `cover` part 提交，服务端直写项目快照桶。 */
-function coverImagePart(id) {
-  return {
-    bytes: COVER_PNG,
-    fileName: `limits-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/** 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 重复 `screenshot` 二进制 part。 */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
+const coverImagePart = (id) =>
+  imagePart('cover', id, { fileName: `limits-${id}.png` });
 
 async function createGameWithVersion(
   author,
diff --git a/scripts/check-game-distribution-purchase-e2e.mjs b/scripts/check-game-distribution-purchase-e2e.mjs
index 20c4ceef3..bb4fff4f6 100644
--- a/scripts/check-game-distribution-purchase-e2e.mjs
+++ b/scripts/check-game-distribution-purchase-e2e.mjs
@@ -51,6 +51,12 @@ import { fileURLToPath } from 'node:url';
 
 import JSZip from 'jszip';
 
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
 const REPO_ROOT = resolve(dirname(fileURLToPath(import.meta.url)), '..');
 const DEV_STACK_PATH = resolve(REPO_ROOT, '.app/dev-stack.json');
@@ -88,12 +94,6 @@ const REQUIRE_PLATFORM_ORIGIN =
   (process.env.E2E_REQUIRE_PLATFORM_ORIGIN ?? '').trim() === '1';
 const GAME_DISTRIBUTION_PURCHASE_SOURCE_TYPE = 'game_purchase';
 
-/** 1x1 透明 PNG：仅用于满足发布必填封面，内容不影响本用例断言。 */
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
-
 let failures = 0;
 let passes = 0;
 let warnings = 0;
@@ -177,20 +177,16 @@ async function api(path, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${path}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -223,36 +219,8 @@ async function registerAccount(prefix) {
   return { status: entry.status, token: entry.data?.token ?? '', phone };
 }
 
-/** 发布用封面图片 part：字节随 `cover` part 提交，服务端直写项目快照桶。 */
-function coverImagePart(id) {
-  return {
-    bytes: COVER_PNG,
-    fileName: `cover-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/** 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 重复 `screenshot` 二进制 part。 */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
+const coverImagePart = (id) =>
+  imagePart('cover', id, { fileName: `cover-${id}.png` });
 
 /**
  * 生成最小可玩发行包：入口页里带唯一标记，用来证明播放会话读到的是同一份包内容。
diff --git a/scripts/check-game-distribution-sandbox-e2e.mjs b/scripts/check-game-distribution-sandbox-e2e.mjs
index f03c1be3b..863add0b9 100644
--- a/scripts/check-game-distribution-sandbox-e2e.mjs
+++ b/scripts/check-game-distribution-sandbox-e2e.mjs
@@ -15,10 +15,12 @@ import path from 'node:path';
 
 import JSZip from 'jszip';
 
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:4198';
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
 const ADMIN_USER = (process.env.E2E_ADMIN_USER ?? '').trim();
@@ -51,20 +53,16 @@ async function api(pathname, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${pathname}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -95,36 +93,8 @@ function gameMetadata(title) {
   };
 }
 
-/** 发布用封面图片 part：字节随 `cover` part 提交，服务端直写项目快照桶。 */
-function coverImagePart(id) {
-  return {
-    bytes: COVER_PNG,
-    fileName: `sandbox-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/** 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 重复 `screenshot` 二进制 part。 */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
+const coverImagePart = (id) =>
+  imagePart('cover', id, { fileName: `sandbox-${id}.png` });
 
 const PROBE_HELPER = "export const marker = 'helper-ok';\n";
 
diff --git a/scripts/check-game-distribution-upload-resume.mjs b/scripts/check-game-distribution-upload-resume.mjs
index a1b0b5365..ad649338a 100644
--- a/scripts/check-game-distribution-upload-resume.mjs
+++ b/scripts/check-game-distribution-upload-resume.mjs
@@ -21,10 +21,12 @@ import path from 'node:path';
 
 import JSZip from 'jszip';
 
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:4198';
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
 const ADMIN_USER = (process.env.E2E_ADMIN_USER ?? '').trim();
@@ -65,20 +67,16 @@ async function api(pathname, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${pathname}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -148,36 +146,8 @@ function gameMetadata(title) {
   };
 }
 
-/** 发布用封面图片 part：字节随 `cover` part 提交，服务端直写项目快照桶。 */
-function coverImagePart(id) {
-  return {
-    bytes: COVER_PNG,
-    fileName: `upload-resume-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/** 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 重复 `screenshot` 二进制 part。 */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
+const coverImagePart = (id) =>
+  imagePart('cover', id, { fileName: `upload-resume-${id}.png` });
 
 // 真实 ZIP（> 8 MiB，随机内容不可压缩），根目录含 index.html，条目数与声明的 packageFileCount 一致。
 async function buildLargeFixtureZip() {
diff --git a/scripts/check-game-distribution-upload-safety.mjs b/scripts/check-game-distribution-upload-safety.mjs
index afaa08486..c1145a0e9 100644
--- a/scripts/check-game-distribution-upload-safety.mjs
+++ b/scripts/check-game-distribution-upload-safety.mjs
@@ -21,10 +21,12 @@ import { createHash } from 'node:crypto';
 
 import JSZip from 'jszip';
 
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:4198';
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
 const ADMIN_USER = (process.env.E2E_ADMIN_USER ?? '').trim();
@@ -59,20 +61,16 @@ async function api(path, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${path}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -112,36 +110,8 @@ function gameMetadata(title) {
   };
 }
 
-/** 发布用封面图片 part：字节随 `cover` part 提交，服务端直写项目快照桶。 */
-function coverImagePart(id) {
-  return {
-    bytes: COVER_PNG,
-    fileName: `upload-safety-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/** 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 重复 `screenshot` 二进制 part。 */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
+const coverImagePart = (id) =>
+  imagePart('cover', id, { fileName: `upload-safety-${id}.png` });
 
 async function main() {
   const adminLogin = await api('/admin/api/login', {
diff --git a/scripts/check-game-distribution-validation-restart-e2e.mjs b/scripts/check-game-distribution-validation-restart-e2e.mjs
index 260e3df03..e2761b6fa 100644
--- a/scripts/check-game-distribution-validation-restart-e2e.mjs
+++ b/scripts/check-game-distribution-validation-restart-e2e.mjs
@@ -15,10 +15,12 @@ import path from 'node:path';
 
 import JSZip from 'jszip';
 
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:8082';
 const API_PORT = Number(new URL(API).port || '80');
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
@@ -59,20 +61,16 @@ async function api(pathname, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${pathname}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -104,36 +102,8 @@ async function adminToken() {
   return token;
 }
 
-/** 发布用封面图片 part：字节随 `cover` part 提交，服务端直写项目快照桶。 */
-function coverImagePart(id) {
-  return {
-    bytes: COVER_PNG,
-    fileName: `restart-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/** 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 重复 `screenshot` 二进制 part。 */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
+const coverImagePart = (id) =>
+  imagePart('cover', id, { fileName: `restart-${id}.png` });
 
 function gameMetadata(title, coverObjectKey) {
   return {
diff --git a/scripts/check-game-distribution-web-a11y-e2e.mjs b/scripts/check-game-distribution-web-a11y-e2e.mjs
index 48ddad423..b8bbf59ef 100644
--- a/scripts/check-game-distribution-web-a11y-e2e.mjs
+++ b/scripts/check-game-distribution-web-a11y-e2e.mjs
@@ -10,10 +10,12 @@ import path from 'node:path';
 
 import JSZip from 'jszip';
 
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const WEB = process.env.E2E_WEB_BASE ?? 'http://127.0.0.1:3000';
 const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:8082';
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
@@ -45,20 +47,16 @@ async function api(pathname, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${pathname}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -77,36 +75,8 @@ async function loadPlaywright() {
   return requireFromDir('playwright');
 }
 
-/** 发布用封面图片 part：字节随 `cover` part 提交，服务端直写项目快照桶。 */
-function coverImagePart(id) {
-  return {
-    bytes: COVER_PNG,
-    fileName: `a11y-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/** 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 重复 `screenshot` 二进制 part。 */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
+const coverImagePart = (id) =>
+  imagePart('cover', id, { fileName: `a11y-${id}.png` });
 
 async function loginThroughWebUi(page, phone) {
   await page.goto(`${WEB}/games`, { waitUntil: 'commit', timeout: 120_000 });
diff --git a/scripts/check-game-distribution-web-e2e.mjs b/scripts/check-game-distribution-web-e2e.mjs
index 727b33b1c..26ec9a05d 100644
--- a/scripts/check-game-distribution-web-e2e.mjs
+++ b/scripts/check-game-distribution-web-e2e.mjs
@@ -12,10 +12,12 @@ import path from 'node:path';
 
 import JSZip from 'jszip';
 
-const COVER_PNG = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
-  'base64',
-);
+import {
+  imagePart,
+  publishFormData,
+  resolveApiRequest,
+} from './game-distribution-e2e-helpers.mjs';
+
 const WEB = process.env.E2E_WEB_BASE ?? 'http://127.0.0.1:3000';
 const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:8082';
 const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
@@ -79,20 +81,16 @@ async function api(pathname, options = {}) {
   } = options;
   const finalHeaders = { ...ENVELOPE, ...headers };
   if (token) finalHeaders.Authorization = `Bearer ${token}`;
-  let finalBody;
-  if (formData) {
-    // multipart/form-data：不手动设 Content-Type，交给 fetch 生成 boundary。
-    finalBody = formData;
-  } else if (binary) {
-    finalBody = binary;
-  } else if (body !== undefined) {
-    finalHeaders['Content-Type'] = 'application/json';
-    finalBody = JSON.stringify(body);
-  }
+  const request = resolveApiRequest({
+    formData,
+    binary,
+    body,
+    headers: finalHeaders,
+  });
   const response = await fetch(`${API}${pathname}`, {
     method,
-    headers: finalHeaders,
-    body: finalBody,
+    headers: request.headers,
+    body: request.body,
   });
   const text = await response.text();
   let json = null;
@@ -110,36 +108,8 @@ async function api(pathname, options = {}) {
   };
 }
 
-/** 发布用封面图片 part：字节随 `cover` part 提交，服务端直写项目快照桶。 */
-function coverImagePart(id) {
-  return {
-    bytes: COVER_PNG,
-    fileName: `web-e2e-${id}.png`,
-    contentType: 'image/png',
-  };
-}
-
-/** 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 重复 `screenshot` 二进制 part。 */
-function publishFormData(metadata, { cover, screenshots = [] } = {}) {
-  const form = new FormData();
-  form.append('metadata', JSON.stringify(metadata));
-  if (cover) {
-    form.append(
-      'cover',
-      new Blob([cover.bytes], { type: cover.contentType }),
-      cover.fileName,
-    );
-  }
-  for (const screenshot of screenshots) {
-    if (!screenshot) continue;
-    form.append(
-      'screenshot',
-      new Blob([screenshot.bytes], { type: screenshot.contentType }),
-      screenshot.fileName,
-    );
-  }
-  return form;
-}
+const coverImagePart = (id) =>
+  imagePart('cover', id, { fileName: `web-e2e-${id}.png` });
 
 async function publishFixtureGame(stamp, title) {
   const adminLogin = await api('/admin/api/login', {
diff --git a/scripts/game-distribution-e2e-helpers.mjs b/scripts/game-distribution-e2e-helpers.mjs
new file mode 100644
index 000000000..8dc3a89f5
--- /dev/null
+++ b/scripts/game-distribution-e2e-helpers.mjs
@@ -0,0 +1,95 @@
+// 游戏分发 E2E 脚本共用的 multipart 发布 helper。
+//
+// 这些脚本都直连 api-server，发布口是同一套契约：`metadata` JSON 文本 part + 可选 `cover`
+// 二进制 part + 按顺序重复的 `screenshot` 二进制 part；各自的 `api()` 也只在 body 形态上分支。
+// 这里收敛这段稳定契约，脚本只保留自己的路径、鉴权头与返回形状差异。
+
+/** 1x1 透明 PNG：仅用于满足发布必填的封面/截图 part，内容不参与断言。 */
+export const COVER_PNG = Buffer.from(
+  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
+  'base64',
+);
+
+/**
+ * 发布用图片 part。
+ *
+ * 默认文件名 `<kind>-<id>.png`、`image/png`；脚本可通过 `options.fileName` 保留自己的前缀，
+ * 或用 `options.bytes` / `options.contentType` 覆盖字节与类型。
+ */
+export function imagePart(kind, id, options = {}) {
+  const {
+    bytes = COVER_PNG,
+    fileName = `${kind}-${id}.png`,
+    contentType = 'image/png',
+  } = options;
+  return { bytes, fileName, contentType };
+}
+
+/**
+ * 封面 part 便捷封装：等价于 `imagePart('cover', id, options)`。
+ *
+ * 脚本可用 `options.fileName` 给出完整文件名，或用 `options.namePrefix` 生成
+ * `<prefix>-<id>.png`。
+ */
+export function coverImagePart(id, options = {}) {
+  const { namePrefix, fileName, ...rest } = options;
+  const resolvedFileName =
+    fileName ?? (namePrefix ? `${namePrefix}-${id}.png` : `cover-${id}.png`);
+  return imagePart('cover', id, { ...rest, fileName: resolvedFileName });
+}
+
+/**
+ * 组装发布请求体：`metadata` 文本 part + 可选 `cover` / 按顺序重复的 `screenshot` 二进制 part。
+ *
+ * `metadata.screenshots` 里的 `null` 槽位按出现顺序消费 `screenshots` 数组里的 part；string
+ * 槽位沿用该 objectKey。调用方负责保证 null 槽位数量与 part 数量一致（不一致服务端会 400）。
+ */
+export function publishFormData(metadata, { cover, screenshots = [] } = {}) {
+  const form = new FormData();
+  form.append('metadata', JSON.stringify(metadata));
+  if (cover) {
+    form.append(
+      'cover',
+      new Blob([cover.bytes], { type: cover.contentType }),
+      cover.fileName,
+    );
+  }
+  for (const screenshot of screenshots) {
+    if (!screenshot) continue;
+    form.append(
+      'screenshot',
+      new Blob([screenshot.bytes], { type: screenshot.contentType }),
+      screenshot.fileName,
+    );
+  }
+  return form;
+}
+
+/**
+ * 推导 `api()` 的最终请求头与请求体。
+ *
+ * - `formData`：multipart/form-data，不手动设 `Content-Type`，交给 fetch 生成 boundary。
+ * - `binary`：直接作为 body（例如分片 PUT 的字节）。
+ * - `body !== undefined`：按 JSON 序列化，并补 `Content-Type: application/json`。
+ *
+ * 调用方先自行合并 `{ ...ENVELOPE, ...headers }` 与 `Authorization`，再把结果作为 `headers`
+ * 传进来；返回值里的 `headers` 是补完 `Content-Type` 后的副本。
+ */
+export function resolveApiRequest({
+  formData,
+  binary,
+  body,
+  headers = {},
+} = {}) {
+  const finalHeaders = { ...headers };
+  let finalBody;
+  if (formData) {
+    finalBody = formData;
+  } else if (binary) {
+    finalBody = binary;
+  } else if (body !== undefined) {
+    finalHeaders['Content-Type'] = 'application/json';
+    finalBody = JSON.stringify(body);
+  }
+  return { headers: finalHeaders, body: finalBody };
+}