diff --git a/src/llm/message-squash.ts b/src/llm/message-squash.ts
index 7e6392b..a01b06d 100644
--- a/src/llm/message-squash.ts
+++ b/src/llm/message-squash.ts
@@ -109,6 +109,11 @@ function prefixInto(message: ChatMessage, prefix: string): ChatMessage {
   return { ...message, content: joinText(prefix, contentOf(message)) } as ChatMessage;
 }
 
+/** 排在末尾、后面没有可吞的消息时，往最后一条**后面**接（前缀会把顺序倒过来）。 */
+function suffixInto(message: ChatMessage, suffix: string): ChatMessage {
+  return { ...message, content: joinText(contentOf(message), suffix) } as ChatMessage;
+}
+
 /**
  * 把所有 system 内容并进**紧随其后**的非 system 消息（无则并回上一条），
  * 使序列只剩 user / assistant。
@@ -140,7 +145,7 @@ function foldSystemMessages(messages: ChatMessage[]): ChatMessage[] {
   if (pending.length > 0) {
     for (let i = out.length - 1; i >= 0; i--) {
       if (!isToolGroupMessage(out[i]!)) {
-        out[i] = prefixInto(out[i]!, pending.splice(0).join("\n\n"));
+        out[i] = suffixInto(out[i]!, pending.splice(0).join("\n\n"));
         break;
       }
     }
diff --git a/src/preset/markers.ts b/src/preset/markers.ts
index 38307b5..c1660a7 100644
--- a/src/preset/markers.ts
+++ b/src/preset/markers.ts
@@ -28,7 +28,7 @@ export const WORLD_BOOK_AFTER = "worldBookAfter";
 export const CURRENT_TURN = "currentTurn";
 export const POST_TURN = "postTurn";
 
-/** 导入时插入的自有洞（不含共用的 chatHistory）。 */
+/** 运行时填洞的四个自有洞（不含共用的 chatHistory）；缺失时自动补进顺序。 */
 export const APP_INSERTED_MARKERS = [
   WORLD_BOOK_BEFORE,
   WORLD_BOOK_AFTER,
@@ -36,8 +36,6 @@ export const APP_INSERTED_MARKERS = [
   POST_TURN,
 ] as const;
 
-const APP_INSERTED_SET = new Set<string>(APP_INSERTED_MARKERS);
-
 type MarkerDef = {
   id: string;
   name: string;
@@ -78,8 +76,10 @@ function reindex(
 }
 
 /**
- * 以 chatHistory 为锚点插入四个自有 marker。
- * 可重复调用：先摘掉已插入的自有洞，再按规则放回。
+ * 以 chatHistory 为锚点补齐四个自有 marker：**只补缺的，不动已有的**。
+ * 已经排进 `prompt_order` 的洞保留作者给的顺序——工作台左轨就是真实发送顺序；
+ * 缺的洞按酒馆的规范位置插进来：历史前 → 对话历史 → 历史后 → 本轮对话 → … → 本轮之后。
+ * 可重复调用：补齐之后再调一次是无操作（之前会把这四个洞重新搅回锚点，覆盖作者排的顺序）。
  */
 export function applyExtendedMarkers(preset: PresetPackage): PresetPackage {
   let prompts = [...preset.prompts];
@@ -87,59 +87,46 @@ export function applyExtendedMarkers(preset: PresetPackage): PresetPackage {
     prompts = upsertMarkerEntry(prompts, def);
   }
 
-  const rawOrder = [...preset.promptOrder]
-    .sort((a, b) => a.orderIndex - b.orderIndex)
-    .filter((item) => !APP_INSERTED_SET.has(item.promptId));
-
-  const histIndex = rawOrder.findIndex(
-    (item) => item.promptId === CHAT_HISTORY_MARKER,
+  const enabledOf = new Map(
+    preset.promptOrder.map((item) => [item.promptId, item.enabled]),
   );
+  const next = [...preset.promptOrder].sort((a, b) => a.orderIndex - b.orderIndex);
+  const has = (id: string) => next.some((item) => item.promptId === id);
+  const indexOf = (id: string) => next.findIndex((item) => item.promptId === id);
+  const insertAt = (index: number, id: string) => {
+    const item: PresetPromptOrderItem = {
+      promptId: id,
+      enabled: enabledOf.get(id) ?? true,
+      orderIndex: 0,
+    };
+    next.splice(Math.max(0, Math.min(index, next.length)), 0, item);
+  };
+
   // 预设自带酒馆的 worldInfoBefore / worldInfoAfter（并启用）时，不插自有的世界书洞：
   // 内容直接填进预设那两条，位置上才对得上酒馆。
-  const hasStBefore = rawOrder.some(
+  const hasStBefore = next.some(
     (item) => item.promptId === WORLD_INFO_BEFORE_MARKER && item.enabled,
   );
-  const hasStAfter = rawOrder.some(
+  const hasStAfter = next.some(
     (item) => item.promptId === WORLD_INFO_AFTER_MARKER && item.enabled,
   );
-  const inserted = (id: string): PresetPromptOrderItem => ({
-    promptId: id,
-    enabled: true,
-    orderIndex: 0,
-  });
 
-  const beforeMarkers = hasStBefore ? [] : [inserted(WORLD_BOOK_BEFORE)];
-  const afterMarkers = hasStAfter ? [] : [inserted(WORLD_BOOK_AFTER)];
-
-  let next: PresetPromptOrderItem[];
-  if (histIndex < 0) {
-    next = reindex([
-      ...rawOrder,
-      ...beforeMarkers,
-      inserted(CHAT_HISTORY_MARKER),
-      ...afterMarkers,
-      inserted(CURRENT_TURN),
-      inserted(POST_TURN),
-    ]);
-  } else {
-    const before = rawOrder.slice(0, histIndex);
-    const history = rawOrder[histIndex]!;
-    const after = rawOrder.slice(histIndex + 1);
-    next = reindex([
-      ...before,
-      ...beforeMarkers,
-      history,
-      ...afterMarkers,
-      inserted(CURRENT_TURN),
-      ...after,
-      inserted(POST_TURN),
-    ]);
+  if (!has(CHAT_HISTORY_MARKER)) insertAt(next.length, CHAT_HISTORY_MARKER);
+  if (!has(WORLD_BOOK_BEFORE) && !hasStBefore) insertAt(indexOf(CHAT_HISTORY_MARKER), WORLD_BOOK_BEFORE);
+  if (!has(WORLD_BOOK_AFTER) && !hasStAfter) insertAt(indexOf(CHAT_HISTORY_MARKER) + 1, WORLD_BOOK_AFTER);
+  if (!has(CURRENT_TURN)) {
+    const afterWorldBook = indexOf(WORLD_BOOK_AFTER);
+    insertAt(
+      afterWorldBook >= 0 ? afterWorldBook + 1 : indexOf(CHAT_HISTORY_MARKER) + 1,
+      CURRENT_TURN,
+    );
   }
+  if (!has(POST_TURN)) insertAt(next.length, POST_TURN);
 
   return {
     ...preset,
     prompts,
-    promptOrder: next,
+    promptOrder: reindex(next),
   };
 }