feat: add isContextOnly flag to extraction messages to prevent repeated extraction

- buildExtractionMessages marks messages with isContextOnly (seq < startIdx)
- formatExtractionTranscript inserts section dividers for mixed context/target
- extractor.js Layer 1 prompt splits context review vs extraction target with guidance
- Add tests/extraction-context-only-flag.mjs (7 test cases)

maintenance/chat-history.js

@@ -286,6 +286,7 @@ export function buildExtractionMessages(chat, startIdx, endIdx, settings) {
       rawContent: String(msg?.mes ?? ""),
       name: String(msg?.name ?? "").trim(),
       speaker: String(msg?.name ?? "").trim(),
+      isContextOnly: index < startIdx,
     });
   }
 

maintenance/extraction-context.js

@@ -307,6 +307,7 @@ function normalizeExtractionMessage(message = {}, index = 0, names = {}) {
     content,
     rawContent,
     sourceType: role === "user" ? "user_input" : "ai_output",
+    isContextOnly: message?.isContextOnly === true,
   };
 }
 
@@ -322,18 +323,38 @@ function countRoles(messages = []) {
 }
 
 export function formatExtractionTranscript(messages = []) {
-  return (Array.isArray(messages) ? messages : [])
-    .map((message, index) => {
-      const seqLabel = Number.isFinite(Number(message?.seq))
-        ? `#${Number(message.seq)}`
-        : `#${index + 1}`;
-      const role = normalizeRole(message?.role || "assistant");
-      const speaker = String(message?.speaker || message?.name || "").trim();
-      const speakerLabel = speaker ? `|${speaker}` : "";
-      return `${seqLabel} [${role}${speakerLabel}]: ${String(message?.content || "")}`;
-    })
-    .filter((item) => String(item || "").trim())
-    .join("\n\n");
+  const safeMessages = Array.isArray(messages) ? messages : [];
+  const hasContextMessages = safeMessages.some((m) => m?.isContextOnly === true);
+  const hasTargetMessages = safeMessages.some((m) => m?.isContextOnly !== true);
+  const lines = [];
+  let inContext = null;
+
+  for (let index = 0; index < safeMessages.length; index += 1) {
+    const message = safeMessages[index];
+    const isContext = message?.isContextOnly === true;
+
+    if (hasContextMessages && hasTargetMessages && isContext !== inContext) {
+      if (isContext) {
+        lines.push("--- 以下是上下文回顾（已提取过），仅供理解剧情 ---");
+      } else {
+        lines.push("--- 以下是本次需要提取记忆的新对话内容 ---");
+      }
+      inContext = isContext;
+    }
+
+    const seqLabel = Number.isFinite(Number(message?.seq))
+      ? `#${Number(message.seq)}`
+      : `#${index + 1}`;
+    const role = normalizeRole(message?.role || "assistant");
+    const speaker = String(message?.speaker || message?.name || "").trim();
+    const speakerLabel = speaker ? `|${speaker}` : "";
+    const line = `${seqLabel} [${role}${speakerLabel}]: ${String(message?.content || "")}`;
+    if (String(line || "").trim()) {
+      lines.push(line);
+    }
+  }
+
+  return lines.join("\n\n");
 }
 
 export function buildExtractionInputContext(

maintenance/extractor.js

@@ -873,6 +873,7 @@ export async function extractMemories({
         content: message?.content,
         speaker: message?.speaker,
         name: message?.name,
+        isContextOnly: message?.isContextOnly === true,
       }))
     : [];
 
@@ -957,15 +958,39 @@ export async function extractMemories({
   // 用户提示词 — Phase 3 分层信息结构
   const userPromptSections = [];
 
-  // Layer 1: 当前对话切片
-  if (dialogueText) {
-    userPromptSections.push("## 当前对话内容（需提取记忆）", dialogueText, "");
-  } else if (structuredMode === "structured" && structuredMessages.length > 0) {
-    userPromptSections.push(
-      "## 当前对话内容（结构化消息，需提取记忆）",
-      "(结构化消息已通过 profile blocks 注入，请参考上方 recentMessages 块。)",
-      "",
-    );
+  // Layer 1: 当前对话切片（区分上下文回顾 vs 提取目标）
+  {
+    const hasContextMessages = structuredMessages.some((m) => m?.isContextOnly === true);
+    const hasTargetMessages = structuredMessages.some((m) => m?.isContextOnly !== true);
+    if (dialogueText) {
+      if (hasContextMessages && hasTargetMessages) {
+        userPromptSections.push(
+          "## 对话内容",
+          "以下对话包含两部分：已提取过的上下文回顾（仅供理解前情）和本次需要提取记忆的新内容。" +
+            "请**只从新内容中提取记忆**，不要重复提取上下文回顾中已有的信息。",
+          dialogueText,
+          "",
+        );
+      } else {
+        userPromptSections.push("## 当前对话内容（需提取记忆）", dialogueText, "");
+      }
+    } else if (structuredMode === "structured" && structuredMessages.length > 0) {
+      if (hasContextMessages && hasTargetMessages) {
+        userPromptSections.push(
+          "## 对话内容（结构化消息）",
+          "以下结构化消息包含两部分：标记为 isContextOnly 的是已提取过的上下文回顾（仅供理解前情），" +
+            "其余是本次需要提取记忆的新内容。请**只从 isContextOnly 为 false 的消息中提取记忆**。" +
+            "(结构化消息已通过 profile blocks 注入，请参考上方 recentMessages 块。)",
+          "",
+        );
+      } else {
+        userPromptSections.push(
+          "## 当前对话内容（结构化消息，需提取记忆）",
+          "(结构化消息已通过 profile blocks 注入，请参考上方 recentMessages 块。)",
+          "",
+        );
+      }
+    }
   }
 
   // Layer 2: 当前图谱状态