diff --git a/docs/qqbot-bangdream-tsugu-global-refactor-plan.md b/docs/qqbot-bangdream-tsugu-global-refactor-plan.md
index cea8ccf..ce5459b 100644
--- a/docs/qqbot-bangdream-tsugu-global-refactor-plan.md
+++ b/docs/qqbot-bangdream-tsugu-global-refactor-plan.md
@@ -360,6 +360,9 @@ export interface TsuguHook {
 - 已新增 `list-frame-spec.spec.ts`，覆盖列表正文宽度、标签/tips 偏移、合并列宽、居中图片换行和左侧竖线尺寸；本地生成 `list-frame-spec-song-136.jpg`、`list-frame-spec-event-50.jpg`、`list-frame-spec-character-1.jpg`，验证列表框架规格收口后查曲/查活动/查角色图片输出正常。
 - 已新增 `canvas/text-spec.ts`，收口文本默认字号、行高比例、baseline、空画布尺寸、混排间距和内联图片缩放计算；`canvas/text.ts` 改为消费 spec，原有文本换行和混排拆分逻辑保持不变。
 - 已新增 `text-spec.spec.ts`，覆盖行高/间距比例、baseline、内联图片缩放和空/单行/多行画布尺寸；本地生成 `text-spec-song-136.jpg`、`text-spec-event-50.jpg`、`text-spec-character-1.jpg`，验证文本规格收口后查曲/查活动/查角色图片输出正常。
+- 已新增 `render-blocks/gacha-simulate-spec.ts`，收口抽卡模拟网格宽度、单抽/汇总混排尺寸、重复卡叠层、数量右对齐和卡池横幅布局；`gacha-simulate.ts` 改为消费 spec，抽卡概率和卡池选择逻辑保持不变。
+- 已新增 `gacha-simulate-spec.spec.ts`，覆盖 10 抽网格、汇总模式、重复卡叠层、计数字样和横幅尺寸；本地生成 `gacha-simulate-spec-10-259.jpg` 和 `gacha-simulate-spec-50-259-after-cache-fix.jpg`，验证抽卡模拟两种布局模式图片输出正常。
+- 抽卡模拟 50 抽 smoke 暴露资源下载短时失败会把 URL 写入无过期错误缓存，导致后续重试直接输出 `asset error`；已改为只有 HTTP 404 进入错误缓存，超时/网络抖动不污染 URL，并新增 `file-cache-client.spec.ts` 覆盖瞬时失败后可再次下载、404 缓存缺失资源两种路径。
 
 ### Phase 6：策略 policy 和时间/档线规则
 
diff --git a/src/qqbot/plugins/bangDream/tsugu/command-renderers/gacha-simulate.ts b/src/qqbot/plugins/bangDream/tsugu/command-renderers/gacha-simulate.ts
index f4b30c7..1df2e2c 100644
--- a/src/qqbot/plugins/bangDream/tsugu/command-renderers/gacha-simulate.ts
+++ b/src/qqbot/plugins/bangDream/tsugu/command-renderers/gacha-simulate.ts
@@ -20,8 +20,16 @@ import {
   pickGachaCardIdByWeight,
   pickGachaRarityByRate,
 } from '@/qqbot/plugins/bangDream/tsugu/models/gacha-policy';
+import {
+  BANGDREAM_GACHA_SIMULATE_SPEC,
+  createGachaBannerCanvasSize,
+  createGachaSimulateWrapOptions,
+  getGachaBannerImageMaxWidth,
+  getGachaCountTextPosition,
+  getGachaDuplicateIconRect,
+  getGachaDuplicateLayerCount,
+} from '@/qqbot/plugins/bangDream/tsugu/render-blocks/gacha-simulate-spec';
 
-const maxWidth = 230 * 5;
 /**
  * 在QQBot 图片视图层中绘制Random卡池。
  *
@@ -36,7 +44,9 @@ export async function drawRandomGacha(
   compress: boolean,
 ): Promise<Array<Buffer | string>> {
   if (isGachaSpinCountTooLarge(times)) {
-    return [`错误: 抽卡次数过多, 请不要超过${BANGDREAM_GACHA_MAX_SPIN_COUNT}次`];
+    return [
+      `错误: 抽卡次数过多, 请不要超过${BANGDREAM_GACHA_MAX_SPIN_COUNT}次`,
+    ];
   }
   if (!gacha.isExist) {
     return ['错误: 该卡池不存在'];
@@ -52,11 +62,8 @@ export async function drawRandomGacha(
       cardImageList.push(await drawGachaCard(getGachaRandomCard(gacha, i)));
     }
     gachaImage = drawTextWithImages({
-      textSize: 230,
-      lineHeight: 230,
       content: cardImageList,
-      maxWidth: maxWidth,
-      spacing: 0,
+      ...createGachaSimulateWrapOptions('single'),
     });
   } else {
     const gachaList: { [cardId: number]: number } = {};
@@ -98,11 +105,8 @@ export async function drawRandomGacha(
     cardImageList.push(...cardImageResults);
 
     gachaImage = drawTextWithImages({
-      textSize: 115,
-      lineHeight: 115,
       content: cardImageList,
-      maxWidth: maxWidth,
-      spacing: 0,
+      ...createGachaSimulateWrapOptions('summary'),
     });
   }
 
@@ -134,37 +138,54 @@ async function drawGachaCard(card: Card, numberOfCard: number = 1) {
     cardIdVisible: true,
   });
   if (numberOfCard > 1) {
-    const canvas = new Canvas(230, 230);
+    const canvas = new Canvas(
+      BANGDREAM_GACHA_SIMULATE_SPEC.card.canvas.width,
+      BANGDREAM_GACHA_SIMULATE_SPEC.card.canvas.height,
+    );
     const ctx = canvas.getContext('2d');
-    const maxTimes = Math.min(6, numberOfCard - 1);
+    const layerCount = getGachaDuplicateLayerCount(numberOfCard);
     const cardIconWithoutId = await drawCardIcon({
       card: card,
       trainingStatus: false,
       cardTypeVisible: false,
       cardIdVisible: false,
     });
-    for (let i = 1; i <= maxTimes; i++) {
-      ctx.drawImage(
-        cardIconWithoutId,
-        35 - (maxTimes - i + 1) * 4,
-        20 - (maxTimes - i + 1) * 4,
-        180,
-        180,
-      );
+    for (let i = 0; i < layerCount; i++) {
+      const rect = getGachaDuplicateIconRect(i, layerCount);
+      ctx.drawImage(cardIconWithoutId, rect.x, rect.y, rect.width, rect.height);
     }
-    ctx.drawImage(cardIconWithId, 35, 20, 180, 210);
+    const iconWithCount = BANGDREAM_GACHA_SIMULATE_SPEC.card.iconWithCount;
+    ctx.drawImage(
+      cardIconWithId,
+      iconWithCount.x,
+      iconWithCount.y,
+      iconWithCount.width,
+      iconWithCount.height,
+    );
+    const countTextSpec = BANGDREAM_GACHA_SIMULATE_SPEC.card.countText;
     const numberText = drawText({
       text: `x${numberOfCard}`,
-      textSize: 30,
-      maxWidth: 80,
-      color: '#A7A7A7',
+      textSize: countTextSpec.textSize,
+      maxWidth: countTextSpec.maxWidth,
+      color: countTextSpec.color,
     });
-    ctx.drawImage(numberText, 215 - numberText.width, 195);
+    const countPosition = getGachaCountTextPosition(numberText.width);
+    ctx.drawImage(numberText, countPosition.x, countPosition.y);
     return canvas;
   } else {
-    const canvas = new Canvas(230, 230);
+    const canvas = new Canvas(
+      BANGDREAM_GACHA_SIMULATE_SPEC.card.canvas.width,
+      BANGDREAM_GACHA_SIMULATE_SPEC.card.canvas.height,
+    );
     const ctx = canvas.getContext('2d');
-    ctx.drawImage(cardIconWithId, 35, 20, 180, 200);
+    const iconSingle = BANGDREAM_GACHA_SIMULATE_SPEC.card.iconSingle;
+    ctx.drawImage(
+      cardIconWithId,
+      iconSingle.x,
+      iconSingle.y,
+      iconSingle.width,
+      iconSingle.height,
+    );
     return canvas;
   }
 }
@@ -195,21 +216,6 @@ function getGachaRandomCard(gacha: Gacha, times: number) {
   return card;
 }
 
-/*
-const okButton = drawRoundedRectWithText({
-    text: 'ok',
-    textColor: '#FFFFFF',
-    textSize: 60,
-    color: '#FE3B73',
-    textAlign: 'center',
-    width: 280,
-    height: 80,
-    radius: 20,
-    strokeColor: '#FFFFFF',
-    strokeWidth: 5,
-})
-*/
-
 //画下方的卡池Banner与抽卡按钮
 /**
  * 在QQBot 图片视图层中绘制卡池横幅。
@@ -219,11 +225,15 @@ const okButton = drawRoundedRectWithText({
 async function drawGachaBanner(gacha: Gacha) {
   const gachaBannerImage = resizeImage({
     image: await drawGachaDataBlock(gacha),
-    widthMax: maxWidth / 2,
+    widthMax: getGachaBannerImageMaxWidth(),
   });
-  const canvas = new Canvas(maxWidth + 200, gachaBannerImage.height);
+  const canvasSize = createGachaBannerCanvasSize(gachaBannerImage.height);
+  const canvas = new Canvas(canvasSize.width, canvasSize.height);
   const ctx = canvas.getContext('2d');
-  //ctx.drawImage(okButton, 1010, 0)
-  ctx.drawImage(gachaBannerImage, 50, 0);
+  ctx.drawImage(
+    gachaBannerImage,
+    BANGDREAM_GACHA_SIMULATE_SPEC.banner.imageX,
+    BANGDREAM_GACHA_SIMULATE_SPEC.banner.imageY,
+  );
   return canvas;
 }
diff --git a/src/qqbot/plugins/bangDream/tsugu/data-clients/file-cache-client.ts b/src/qqbot/plugins/bangDream/tsugu/data-clients/file-cache-client.ts
index 7978f21..d98ce0d 100644
--- a/src/qqbot/plugins/bangDream/tsugu/data-clients/file-cache-client.ts
+++ b/src/qqbot/plugins/bangDream/tsugu/data-clients/file-cache-client.ts
@@ -6,7 +6,8 @@ import {
   normalizeBangDreamPositiveInteger,
 } from '@/qqbot/plugins/bangDream/tsugu/runtime/runtime-options';
 
-const errUrl: string[] = [];
+const errorUrlCache: { [url: string]: number } = {};
+const ERROR_URL_CACHE_EXPIRY_MS = 12 * 60 * 60 * 1000;
 const DEFAULT_REQUEST_TIMEOUT_MS = 8000;
 
 function getRequestTimeoutMs(): number {
@@ -35,8 +36,8 @@ export async function download(
     ensureDirectoryExists(directory);
   }
   try {
-    if (errUrl.includes(url)) {
-      throw new Error('downloadFile: errUrl.includes(url)');
+    if (isErrorUrlCacheActive(url)) {
+      throw new Error('downloadFile: errorUrlCache includes url');
     }
     let eTag: string | undefined;
     const cacheFilePath = path.join(directory || '', `${fileName || ''}`);
@@ -83,7 +84,9 @@ export async function download(
     }
     return fileBuffer;
   } catch (e) {
-    errUrl.push(url);
+    if (getErrorResponseStatus(e) === 404) {
+      errorUrlCache[url] = Date.now();
+    }
     if (url.includes('.png')) {
       throw e;
     } else {
@@ -94,6 +97,26 @@ export async function download(
   }
 }
 
+function isErrorUrlCacheActive(url: string): boolean {
+  const cachedAt = errorUrlCache[url];
+  if (cachedAt == null) {
+    return false;
+  }
+  if (Date.now() - cachedAt >= ERROR_URL_CACHE_EXPIRY_MS) {
+    delete errorUrlCache[url];
+    return false;
+  }
+  return true;
+}
+
+function getErrorResponseStatus(error: unknown): number | undefined {
+  if (typeof error !== 'object' || error == null || !('response' in error)) {
+    return undefined;
+  }
+  const response = (error as { response?: { status?: number } }).response;
+  return response?.status;
+}
+
 /**
  * 在数据下载与缓存层中确保DirectoryExists。
  *
diff --git a/src/qqbot/plugins/bangDream/tsugu/render-blocks/gacha-simulate-spec.ts b/src/qqbot/plugins/bangDream/tsugu/render-blocks/gacha-simulate-spec.ts
new file mode 100644
index 0000000..9a16f70
--- /dev/null
+++ b/src/qqbot/plugins/bangDream/tsugu/render-blocks/gacha-simulate-spec.ts
@@ -0,0 +1,149 @@
+export interface GachaSimulateRect {
+  height: number;
+  width: number;
+  x: number;
+  y: number;
+}
+
+export interface GachaSimulatePoint {
+  x: number;
+  y: number;
+}
+
+export const BANGDREAM_GACHA_SIMULATE_SPEC = {
+  banner: {
+    extraWidth: 200,
+    imageX: 50,
+    imageY: 0,
+    maxWidthRatio: 1 / 2,
+  },
+  card: {
+    canvas: { height: 230, width: 230 },
+    countText: {
+      color: '#A7A7A7',
+      maxWidth: 80,
+      rightX: 215,
+      textSize: 30,
+      y: 195,
+    },
+    duplicateIcon: {
+      height: 180,
+      maxLayerCount: 6,
+      offsetStep: 4,
+      width: 180,
+      x: 35,
+      y: 20,
+    },
+    iconSingle: { height: 200, width: 180, x: 35, y: 20 },
+    iconWithCount: { height: 210, width: 180, x: 35, y: 20 },
+  },
+  grid: {
+    columns: 5,
+    single: { lineHeight: 230, textSize: 230 },
+    spacing: 0,
+    summary: { lineHeight: 115, textSize: 115 },
+  },
+} as const;
+
+/**
+ * 获取抽卡结果网格最大宽度。
+ */
+export function getGachaSimulateGridMaxWidth(): number {
+  return (
+    BANGDREAM_GACHA_SIMULATE_SPEC.card.canvas.width *
+    BANGDREAM_GACHA_SIMULATE_SPEC.grid.columns
+  );
+}
+
+/**
+ * 创建抽卡结果图片混排参数。
+ *
+ * @param mode - 单次少量抽卡或汇总抽卡模式。
+ */
+export function createGachaSimulateWrapOptions(mode: 'single' | 'summary'): {
+  lineHeight: number;
+  maxWidth: number;
+  spacing: number;
+  textSize: number;
+} {
+  const sizeSpec = BANGDREAM_GACHA_SIMULATE_SPEC.grid[mode];
+  return {
+    lineHeight: sizeSpec.lineHeight,
+    maxWidth: getGachaSimulateGridMaxWidth(),
+    spacing: BANGDREAM_GACHA_SIMULATE_SPEC.grid.spacing,
+    textSize: sizeSpec.textSize,
+  };
+}
+
+/**
+ * 计算重复卡牌阴影层数。
+ *
+ * @param numberOfCard - 同一卡牌抽到的数量。
+ */
+export function getGachaDuplicateLayerCount(numberOfCard: number): number {
+  return Math.min(
+    BANGDREAM_GACHA_SIMULATE_SPEC.card.duplicateIcon.maxLayerCount,
+    Math.max(0, numberOfCard - 1),
+  );
+}
+
+/**
+ * 计算重复卡牌阴影层绘制区域。
+ *
+ * @param layerIndex - 从远到近的 0 基层索引。
+ * @param layerCount - 阴影总层数。
+ */
+export function getGachaDuplicateIconRect(
+  layerIndex: number,
+  layerCount: number,
+): GachaSimulateRect {
+  const duplicateSpec = BANGDREAM_GACHA_SIMULATE_SPEC.card.duplicateIcon;
+  const offset = (layerCount - layerIndex) * duplicateSpec.offsetStep;
+  return {
+    height: duplicateSpec.height,
+    width: duplicateSpec.width,
+    x: duplicateSpec.x - offset,
+    y: duplicateSpec.y - offset,
+  };
+}
+
+/**
+ * 根据计数字样宽度计算右对齐绘制位置。
+ *
+ * @param textWidth - 计数字样图片宽度。
+ */
+export function getGachaCountTextPosition(
+  textWidth: number,
+): GachaSimulatePoint {
+  return {
+    x: BANGDREAM_GACHA_SIMULATE_SPEC.card.countText.rightX - textWidth,
+    y: BANGDREAM_GACHA_SIMULATE_SPEC.card.countText.y,
+  };
+}
+
+/**
+ * 获取抽卡横幅最大内容宽度。
+ */
+export function getGachaBannerImageMaxWidth(): number {
+  return (
+    getGachaSimulateGridMaxWidth() *
+    BANGDREAM_GACHA_SIMULATE_SPEC.banner.maxWidthRatio
+  );
+}
+
+/**
+ * 根据横幅内容高度计算外层画布尺寸。
+ *
+ * @param imageHeight - 横幅内容高度。
+ */
+export function createGachaBannerCanvasSize(imageHeight: number): {
+  height: number;
+  width: number;
+} {
+  return {
+    height: imageHeight,
+    width:
+      getGachaSimulateGridMaxWidth() +
+      BANGDREAM_GACHA_SIMULATE_SPEC.banner.extraWidth,
+  };
+}
diff --git a/test/qqbot/plugins/bangDream/tsugu/file-cache-client.spec.ts b/test/qqbot/plugins/bangDream/tsugu/file-cache-client.spec.ts
new file mode 100644
index 0000000..aab4c44
--- /dev/null
+++ b/test/qqbot/plugins/bangDream/tsugu/file-cache-client.spec.ts
@@ -0,0 +1,53 @@
+describe('BangDream file cache client', () => {
+  beforeEach(() => {
+    jest.resetModules();
+    jest.clearAllMocks();
+  });
+
+  it('does not poison png url cache after transient network failures', async () => {
+    const imageBuffer = Buffer.from('png-data');
+    const get = jest
+      .fn()
+      .mockRejectedValueOnce(new Error('timeout of 8000ms exceeded'))
+      .mockResolvedValueOnce({ data: imageBuffer, headers: {} });
+
+    jest.doMock('axios', () => ({
+      __esModule: true,
+      default: { get },
+    }));
+
+    const { download } =
+      await import('@/qqbot/plugins/bangDream/tsugu/data-clients/file-cache-client');
+
+    await expect(download('https://example.com/card.png')).rejects.toThrow(
+      'timeout of 8000ms exceeded',
+    );
+    await expect(download('https://example.com/card.png')).resolves.toEqual(
+      imageBuffer,
+    );
+    expect(get).toHaveBeenCalledTimes(2);
+  });
+
+  it('keeps missing png urls in the error cache', async () => {
+    const notFoundError = Object.assign(new Error('not found'), {
+      response: { status: 404 },
+    });
+    const get = jest.fn().mockRejectedValueOnce(notFoundError);
+
+    jest.doMock('axios', () => ({
+      __esModule: true,
+      default: { get },
+    }));
+
+    const { download } =
+      await import('@/qqbot/plugins/bangDream/tsugu/data-clients/file-cache-client');
+
+    await expect(download('https://example.com/missing.png')).rejects.toThrow(
+      'not found',
+    );
+    await expect(download('https://example.com/missing.png')).rejects.toThrow(
+      'errorUrlCache includes url',
+    );
+    expect(get).toHaveBeenCalledTimes(1);
+  });
+});
diff --git a/test/qqbot/plugins/bangDream/tsugu/gacha-simulate-spec.spec.ts b/test/qqbot/plugins/bangDream/tsugu/gacha-simulate-spec.spec.ts
new file mode 100644
index 0000000..6852e88
--- /dev/null
+++ b/test/qqbot/plugins/bangDream/tsugu/gacha-simulate-spec.spec.ts
@@ -0,0 +1,60 @@
+import {
+  BANGDREAM_GACHA_SIMULATE_SPEC,
+  createGachaBannerCanvasSize,
+  createGachaSimulateWrapOptions,
+  getGachaBannerImageMaxWidth,
+  getGachaCountTextPosition,
+  getGachaDuplicateIconRect,
+  getGachaDuplicateLayerCount,
+  getGachaSimulateGridMaxWidth,
+} from '@/qqbot/plugins/bangDream/tsugu/render-blocks/gacha-simulate-spec';
+
+describe('BangDream gacha simulate spec', () => {
+  it('keeps grid widths and wrap modes stable', () => {
+    expect(getGachaSimulateGridMaxWidth()).toBe(1150);
+    expect(createGachaSimulateWrapOptions('single')).toEqual({
+      lineHeight: 230,
+      maxWidth: 1150,
+      spacing: 0,
+      textSize: 230,
+    });
+    expect(createGachaSimulateWrapOptions('summary')).toEqual({
+      lineHeight: 115,
+      maxWidth: 1150,
+      spacing: 0,
+      textSize: 115,
+    });
+  });
+
+  it('caps duplicate card shadow layers', () => {
+    expect(getGachaDuplicateLayerCount(1)).toBe(0);
+    expect(getGachaDuplicateLayerCount(2)).toBe(1);
+    expect(getGachaDuplicateLayerCount(99)).toBe(
+      BANGDREAM_GACHA_SIMULATE_SPEC.card.duplicateIcon.maxLayerCount,
+    );
+  });
+
+  it('positions duplicate card layers from back to front', () => {
+    expect(getGachaDuplicateIconRect(0, 6)).toEqual({
+      height: 180,
+      width: 180,
+      x: 11,
+      y: -4,
+    });
+    expect(getGachaDuplicateIconRect(5, 6)).toEqual({
+      height: 180,
+      width: 180,
+      x: 31,
+      y: 16,
+    });
+  });
+
+  it('keeps count text and banner layout stable', () => {
+    expect(getGachaCountTextPosition(42)).toEqual({ x: 173, y: 195 });
+    expect(getGachaBannerImageMaxWidth()).toBe(575);
+    expect(createGachaBannerCanvasSize(320)).toEqual({
+      height: 320,
+      width: 1350,
+    });
+  });
+});