diff --git a/core/main_terminal_parts/context/messages.py b/core/main_terminal_parts/context/messages.py
index 6cc724d8..37002eac 100644
--- a/core/main_terminal_parts/context/messages.py
+++ b/core/main_terminal_parts/context/messages.py
@@ -125,9 +125,23 @@ class MessagesMixin:
                         logger.warning(f"[messages] 加载多智能体主 prompt 失败: {exc}")
                 system_prompt_template = self.load_prompt(prompt_name)
                 # main_system.txt / main_system_vl.txt 仅使用 {model_description}
-                return system_prompt_template.format(
+                base_prompt = system_prompt_template.format(
                     model_description=prompt_replacements.get("model_description", "")
                 )
+                # 修改留痕附言：开关开启且 conversation_id 可用时追加独立 prompt 段落
+                # （含本对话专属留痕目录；冻结在 prompt 中，与该对话终身一致）
+                try:
+                    from modules.modify_history import build_modify_history_prompt_note
+                    note = build_modify_history_prompt_note(
+                        project_path=getattr(self, "project_path", None),
+                        data_dir=getattr(self, "data_dir", None),
+                        conversation_id=getattr(getattr(self, "context_manager", None), "current_conversation_id", None),
+                    )
+                    if note:
+                        base_prompt = f"{base_prompt}\n\n{note}"
+                except Exception as exc:
+                    logger.warning(f"[messages] 构建修改留痕 prompt 失败: {exc}")
+                return base_prompt
 
             main_system_frozen_key = (
                 "frozen_main_system_prompt_multi_agent"
diff --git a/modules/edit_summary.py b/modules/edit_summary.py
index e221217e..2bea3266 100644
--- a/modules/edit_summary.py
+++ b/modules/edit_summary.py
@@ -163,6 +163,28 @@ def _find_current_work_user_message(context_manager: Any) -> Optional[Dict[str,
     return None
 
 
+def _strip_fulltext_for_broadcast(summary: Dict[str, Any]) -> Dict[str, Any]:
+    """广播副本剥离 current_text（前端只用 lines/计数，且全文可能很大）。
+
+    持久化的对话 JSON 保留 current_text，供修改留痕（modify_history）重建 diff。
+    """
+    files = summary.get("files")
+    if not isinstance(files, list):
+        return summary
+    stripped_files: List[Dict[str, Any]] = []
+    changed = False
+    for entry in files:
+        if isinstance(entry, dict) and "current_text" in entry:
+            entry = {k: v for k, v in entry.items() if k != "current_text"}
+            changed = True
+        stripped_files.append(entry)
+    if not changed:
+        return summary
+    out = dict(summary)
+    out["files"] = stripped_files
+    return out
+
+
 def _persist_and_broadcast(
     context_manager: Any,
     conversation_id: str,
@@ -170,7 +192,13 @@ def _persist_and_broadcast(
     summary: Dict[str, Any],
     web_callback: WebCallback,
 ) -> None:
-    """持久化对话并广播最新编辑摘要。"""
+    """持久化对话并广播最新编辑摘要；同步刷新修改留痕文件。"""
+    # 实时修改留痕：每次摘要变化即重渲染本轮 diff 文件（编辑时刻内容，零磁盘依赖）
+    try:
+        from modules.modify_history import update_modify_history_for_task
+        update_modify_history_for_task(context_manager, msg, summary)
+    except Exception as exc:
+        print(f"⚠️ 修改留痕实时写入失败: {exc}")
     try:
         context_manager.auto_save_conversation(force=True)
     except Exception as exc:
@@ -180,7 +208,7 @@ def _persist_and_broadcast(
             web_callback("edit_summary_updated", {
                 "conversation_id": conversation_id,
                 "message_id": msg.get("message_id"),
-                "edit_summary": summary,
+                "edit_summary": _strip_fulltext_for_broadcast(summary),
             })
         except Exception:
             pass
@@ -246,12 +274,16 @@ def update_edit_summary(
         status = "added" if entry.get("baseline") is None and not entry.get("baseline_truncated") else "modified"
 
         now_iso = datetime.now().isoformat()
+        current_too_large = isinstance(current_text, str) and len(current_text) > MAX_BASELINE_CHARS
         entry.update({
             "status": status,
             "added": diff["added"],
             "removed": diff["removed"],
             "lines": diff["lines"],
             "truncated": bool(diff["truncated"]) or bool(entry.get("baseline_truncated")),
+            # 编辑时刻的最新全文：供修改留痕重建 diff，不依赖任务结束时的磁盘状态
+            "current_text": None if current_too_large else current_text,
+            "current_truncated": current_too_large,
             "updated_at": now_iso,
         })
         summary["updated_at"] = now_iso
diff --git a/modules/modify_history.py b/modules/modify_history.py
new file mode 100644
index 00000000..cf1933b2
--- /dev/null
+++ b/modules/modify_history.py
@@ -0,0 +1,465 @@
+"""修改留痕（Modify History）：把本轮工作的净修改实时落盘为增强版 unified diff。
+
+设计要点（已与用户确认）：
+- **实时写入**：与编辑摘要（edit_summary）完全同步——每次 write_file / edit_file /
+  delete_file / rename_file 引起摘要变化时，立即重渲染本轮留痕文件
+  （``update_modify_history_for_task``，挂在 ``modules/edit_summary._persist_and_broadcast``）。
+  任务中途异常停止，留痕也保留到最后一次编辑的状态。
+- **零磁盘依赖**：diff 的新侧内容来自 edit_summary entry 在编辑时刻记录的
+  ``current_text``（全文，与 baseline 同享 400KB 上限），不读任务结束时的磁盘——
+  ``run_command`` 对文件的改动/删除不会混入留痕（用户定义：只记录原生编辑工具）。
+- **任务结束收尾**（``finalize_modify_history_for_task``，挂在
+  ``server/chat_flow_task_main.finalize_user_work_timer``）：更新头部完成时间，
+  并做文件存在性检查——任务结束时已不存在（被 rm/移动）的文件，小节转为
+  ``/dev/null → 最后内容`` 的 new file diff 并标注，``git apply`` 可直接恢复该文件。
+- 输出：``<工作区>/.astrion/modify_history/<conversation_id>/<用户输入截断>_<任务开始时间>.diff``
+  —— 一次任务（一条用户输入）一个文件。
+- 格式：``#`` 注释头（任务信息）+ 每文件小节注释 + 标准 ``diff --git`` 主体。
+  注释行在 diff 块之外，不影响 ``git apply`` / ``patch``（已实测验证）：
+  文件处于修改前状态时 ``git apply`` 重做，处于修改后状态时 ``git apply -R`` 撤销。
+- 直接 IO 写入：绕开 write_file / edit_file 工具层，不触发深度备份
+  （shallow_versioning.track_edit）与编辑摘要，零递归。
+- 开关：个性化 ``modify_history_enabled``（默认开启）；关闭时既不落盘也不注入
+  system prompt 附言。
+- 已知边界：baseline 或 current 超 400KB 被截断的文件无法重建完整 diff，
+  小节内会明确标注，仅保留计数。
+"""
+
+from __future__ import annotations
+
+import difflib
+import logging
+import re
+from datetime import datetime
+from pathlib import Path
+from typing import Any, Dict, List, Optional
+
+logger = logging.getLogger(__name__)
+
+_ASTRION_DIR_NAME = ".astrion"
+MODIFY_HISTORY_DIR_NAME = "modify_history"
+_PROMPT_FILE_NAME = "modify_history.txt"
+
+_COMMENT_BAR_HEAVY = "# " + "═" * 60
+_COMMENT_BAR_LIGHT = "# " + "─" * 60
+
+# summary 中记录本轮留痕文件名的私有字段（随对话 JSON 持久化，供收尾定位同一文件）
+_HISTORY_FILE_KEY = "_history_file"
+
+# 文件名中用户输入片段的长度上限与文件系统非法字符
+_FILENAME_INPUT_MAX_CHARS = 40
+_FILENAME_ILLEGAL_RE = re.compile(r'[/\\:*?"<>|\x00-\x1f]')
+
+
+# ---------------------------------------------------------------------------
+# 路径与开关
+# ---------------------------------------------------------------------------
+
+
+def get_modify_history_dir(project_path: Any, conversation_id: Optional[str]) -> Optional[Path]:
+    """本对话的留痕目录；conversation_id 缺失时返回 None。"""
+    conv_id = str(conversation_id or "").strip()
+    if not project_path or not conv_id:
+        return None
+    return (
+        Path(project_path).expanduser().resolve()
+        / _ASTRION_DIR_NAME
+        / MODIFY_HISTORY_DIR_NAME
+        / conv_id
+    )
+
+
+def is_modify_history_enabled(data_dir: Any) -> bool:
+    """读取个性化开关；读取失败按默认开启处理。"""
+    try:
+        from modules.personalization_manager import load_personalization_config
+
+        config = load_personalization_config(data_dir)
+        return bool(config.get("modify_history_enabled", True))
+    except Exception:
+        return True
+
+
+# ---------------------------------------------------------------------------
+# system prompt 附言
+# ---------------------------------------------------------------------------
+
+
+def build_modify_history_prompt_note(
+    *,
+    project_path: Any,
+    data_dir: Any,
+    conversation_id: Optional[str],
+) -> str:
+    """构建注入 frozen system prompt 的留痕说明段落；开关关闭或信息缺失时返回空串。"""
+    if not is_modify_history_enabled(data_dir):
+        return ""
+    history_dir = get_modify_history_dir(project_path, conversation_id)
+    if history_dir is None:
+        return ""
+    try:
+        prompt_path = Path(__file__).resolve().parent.parent / "prompts" / _PROMPT_FILE_NAME
+        template = prompt_path.read_text(encoding="utf-8")
+        return template.format(modify_history_dir=str(history_dir)).strip()
+    except Exception as exc:
+        logger.warning(f"[modify_history] 加载留痕 prompt 失败: {exc}")
+        return ""
+
+
+# ---------------------------------------------------------------------------
+# diff 渲染
+# ---------------------------------------------------------------------------
+
+
+def _split_text_lines(text: Optional[str]) -> List[str]:
+    if not text:
+        return []
+    return str(text).splitlines()
+
+
+def _render_file_diff_body(path: str, status: str, old_text: Optional[str], new_text: str) -> List[str]:
+    """单文件的标准 diff 主体（diff --git 头 + hunk），保证 git apply 可用。"""
+    out: List[str] = [f"diff --git a/{path} b/{path}"]
+    if status == "added":
+        out.append("new file mode 100644")
+        out.append("--- /dev/null")
+    else:
+        out.append(f"--- a/{path}")
+    out.append(f"+++ b/{path}")
+    old_lines = _split_text_lines(old_text)
+    new_lines = _split_text_lines(new_text)
+    diff_iter = difflib.unified_diff(
+        old_lines,
+        new_lines,
+        fromfile=f"a/{path}",
+        tofile=f"b/{path}",
+        n=3,
+        lineterm="",
+    )
+    for line in list(diff_iter)[2:]:  # 跳过 difflib 自产 ---/+++ 头，使用自拼头部
+        out.append(line)
+    return out
+
+
+def render_modify_history_diff(
+    *,
+    conversation_id: str,
+    user_message_text: str,
+    started_at: Optional[str],
+    finished_at: Optional[str],
+    files: List[Dict[str, Any]],
+) -> str:
+    """渲染完整留痕文件内容。
+
+    files 元素：
+      path, status, added, removed, old_text, new_text,
+      truncated            —— baseline/current 超上限，仅保留计数，不产 diff 主体
+      missing_at_finalize  —— 收尾时文件已不存在：主体改为 /dev/null→new_text，可恢复
+      unrecoverable        —— 文件已不存在且无内容记录：仅标注，不产 diff 主体
+    """
+    total_added = sum(int(f.get("added") or 0) for f in files)
+    total_removed = sum(int(f.get("removed") or 0) for f in files)
+    task_summary = " ".join(str(user_message_text or "").split())
+    if len(task_summary) > 200:
+        task_summary = task_summary[:200] + "…"
+
+    lines: List[str] = [
+        _COMMENT_BAR_HEAVY,
+        "# 修改记录（Astrion Modify History）",
+        _COMMENT_BAR_HEAVY,
+        f"# 对话:     {conversation_id}",
+        f"# 任务:     {task_summary}",
+        f"# 时间:     {started_at or '?'} → {finished_at or '?'}",
+        f"# 合计:     {len(files)} 个文件，+{total_added} / −{total_removed}",
+        "#",
+        "# 恢复方式:",
+        "#   重做本次修改（文件处于修改前状态时）: git apply 本文件",
+        "#   撤销本次修改（文件处于修改后状态时）: git apply -R 本文件",
+        "#   恢复已删除文件（小节标注「已不存在」时）: git apply 本文件",
+        "#   所有 # 注释行不影响 git apply / patch，无需剔除",
+        "",
+    ]
+
+    for index, entry in enumerate(files, 1):
+        path = str(entry.get("path") or "")
+        status = str(entry.get("status") or "modified")
+        status_label = "新建" if status == "added" else "修改"
+        added = int(entry.get("added") or 0)
+        removed = int(entry.get("removed") or 0)
+        truncated = bool(entry.get("truncated"))
+        missing = bool(entry.get("missing_at_finalize"))
+        unrecoverable = bool(entry.get("unrecoverable"))
+        lines.extend(
+            [
+                _COMMENT_BAR_LIGHT,
+                f"# [{index}/{len(files)}] {path}",
+                f"#       {status_label} · +{added} / −{removed}",
+            ]
+        )
+        if truncated:
+            lines.append("#       ⚠ 文件内容超出保存上限（400KB），无法重建完整 diff，仅保留计数")
+        if missing and not unrecoverable:
+            lines.append("#       ⚠ 文件在任务结束时已不存在（可能被删除/移动），以下按其最后记录内容完整保留，git apply 可直接恢复")
+        if unrecoverable:
+            lines.append("#       ⚠ 文件在任务结束时已不存在，且本轮无内容记录，无法重建")
+        lines.append(_COMMENT_BAR_LIGHT)
+        if truncated or unrecoverable:
+            lines.append("")
+            continue
+        if missing:
+            # 已消失文件：产出 new file diff（/dev/null → 最后内容），git apply 即恢复
+            lines.extend(
+                _render_file_diff_body(
+                    path=path,
+                    status="added",
+                    old_text=None,
+                    new_text=str(entry.get("new_text") or ""),
+                )
+            )
+        else:
+            lines.extend(
+                _render_file_diff_body(
+                    path=path,
+                    status=status,
+                    old_text=entry.get("old_text"),
+                    new_text=str(entry.get("new_text") or ""),
+                )
+            )
+        lines.append("")
+
+    return "\n".join(lines).rstrip("\n") + "\n"
+
+
+# ---------------------------------------------------------------------------
+# 任务信息辅助
+# ---------------------------------------------------------------------------
+
+
+def _parse_iso(value: Optional[str]) -> Optional[datetime]:
+    if not value:
+        return None
+    try:
+        return datetime.fromisoformat(str(value).replace("Z", "+00:00")).replace(tzinfo=None)
+    except Exception:
+        return None
+
+
+def _task_started_at(msg: Dict[str, Any]) -> Optional[str]:
+    metadata = msg.get("metadata") or {}
+    timer = metadata.get("work_timer")
+    if isinstance(timer, dict) and timer.get("started_at"):
+        return str(timer.get("started_at"))
+    return msg.get("timestamp") or None
+
+
+def _message_text(msg: Dict[str, Any]) -> str:
+    content = msg.get("content")
+    if isinstance(content, str):
+        return content
+    if isinstance(content, list):
+        # 多模态消息：拼接其中的文本片段
+        parts = []
+        for item in content:
+            if isinstance(item, dict) and isinstance(item.get("text"), str):
+                parts.append(item["text"])
+        return " ".join(parts)
+    return str(content or "")
+
+
+def _sanitize_input_for_filename(text: Any, max_chars: int = _FILENAME_INPUT_MAX_CHARS) -> str:
+    """用户输入转文件名片段：压缩空白、非法字符替换为 _、截断；空结果回退 task。"""
+    cleaned = " ".join(str(text or "").split())
+    cleaned = _FILENAME_ILLEGAL_RE.sub("_", cleaned)
+    cleaned = re.sub(r"_+", "_", cleaned).strip(" ._")
+    if len(cleaned) > max_chars:
+        cleaned = cleaned[:max_chars].rstrip(" ._")
+    return cleaned or "task"
+
+
+def _ensure_history_file_name(
+    msg: Dict[str, Any],
+    summary: Dict[str, Any],
+    *,
+    history_dir: Optional[Path] = None,
+) -> str:
+    """本轮留痕文件名：<用户输入截断>_<任务开始时间>.diff；首次生成后存入 summary 复用。
+
+    同对话内输入（截断后）同名且同窗时间戳冲突时追加 _2/_3 序号，避免后轮覆盖前轮。
+    """
+    existing = summary.get(_HISTORY_FILE_KEY)
+    if isinstance(existing, str) and existing.strip():
+        return existing.strip()
+    input_part = _sanitize_input_for_filename(_message_text(msg))
+    dt = _parse_iso(_task_started_at(msg)) or datetime.now()
+    base = f"{input_part}_{dt.strftime('%Y-%m-%d_%H%M%S_%f')[:-3]}"
+    name = f"{base}.diff"
+    if history_dir is not None:
+        seq = 2
+        while (history_dir / name).exists():
+            name = f"{base}_{seq}.diff"
+            seq += 1
+    summary[_HISTORY_FILE_KEY] = name
+    return name
+
+
+def _build_files_payload(
+    files: List[Any],
+    *,
+    project_root: Optional[Path] = None,
+) -> List[Dict[str, Any]]:
+    """把 edit_summary entries 转成渲染载荷；数据源为编辑时刻记录的 baseline/current。
+
+    project_root 提供时做存在性检查（任务结束收尾）：已消失的文件按
+    missing_at_finalize（有内容记录，可恢复）或 unrecoverable（无记录）处理。
+    """
+    payload: List[Dict[str, Any]] = []
+    for entry in files:
+        if not isinstance(entry, dict):
+            continue
+        rel_path = str(entry.get("path") or "").strip()
+        if not rel_path:
+            continue
+        current = entry.get("current_text")
+        truncated = (
+            bool(entry.get("truncated"))
+            or bool(entry.get("baseline_truncated"))
+            or bool(entry.get("current_truncated"))
+        )
+        item: Dict[str, Any] = {
+            "path": rel_path,
+            "status": str(entry.get("status") or "modified"),
+            "added": entry.get("added") or 0,
+            "removed": entry.get("removed") or 0,
+            "old_text": entry.get("baseline"),
+            "new_text": current if isinstance(current, str) else "",
+            "truncated": truncated,
+        }
+        if project_root is not None:
+            try:
+                exists = (project_root / rel_path).is_file()
+            except Exception:
+                exists = True  # 检查本身失败时按存在处理，不误标
+            if not exists:
+                if isinstance(current, str) and not truncated:
+                    item["missing_at_finalize"] = True
+                else:
+                    item["unrecoverable"] = True
+        payload.append(item)
+    return payload
+
+
+def _write_history_file(history_dir: Path, file_name: str, content: str) -> str:
+    history_dir.mkdir(parents=True, exist_ok=True)
+    target = history_dir / file_name
+    target.write_text(content, encoding="utf-8")
+    return str(target)
+
+
+# ---------------------------------------------------------------------------
+# 实时写入（每次编辑后）与任务收尾（任务结束时）
+# ---------------------------------------------------------------------------
+
+
+def update_modify_history_for_task(
+    context_manager: Any,
+    msg: Dict[str, Any],
+    summary: Dict[str, Any],
+) -> Optional[str]:
+    """编辑摘要每次变化时重渲染本轮留痕文件（实时）。
+
+    由 modules/edit_summary._persist_and_broadcast 调用（覆盖 update/remove/rename
+    三条路径）；数据源全部来自 summary entries（baseline + current_text），不读磁盘。
+    返回留痕文件路径；开关关闭/信息缺失/无有效文件时返回 None。
+    """
+    try:
+        if not isinstance(summary, dict):
+            return None
+        project_path = getattr(context_manager, "project_path", None)
+        data_dir = getattr(context_manager, "data_dir", None)
+        conversation_id = getattr(context_manager, "current_conversation_id", None)
+        history_dir = get_modify_history_dir(project_path, conversation_id)
+        if history_dir is None:
+            return None
+
+        files = summary.get("files")
+        if not isinstance(files, list) or not files:
+            # 本轮编辑已全部回滚（如 write 后又 delete_file）：移除已生成的留痕文件
+            existing_name = summary.get(_HISTORY_FILE_KEY)
+            if isinstance(existing_name, str) and existing_name.strip():
+                if not is_modify_history_enabled(data_dir):
+                    return None
+                try:
+                    (history_dir / existing_name.strip()).unlink(missing_ok=True)
+                except Exception:
+                    pass
+                summary.pop(_HISTORY_FILE_KEY, None)
+            return None
+
+        if not is_modify_history_enabled(data_dir):
+            return None
+
+        file_name = _ensure_history_file_name(msg, summary, history_dir=history_dir)
+        payload = _build_files_payload(files)
+        if not payload:
+            return None
+        content = render_modify_history_diff(
+            conversation_id=str(conversation_id),
+            user_message_text=_message_text(msg),
+            started_at=_task_started_at(msg),
+            finished_at=datetime.now().isoformat(timespec="seconds"),
+            files=payload,
+        )
+        return _write_history_file(history_dir, file_name, content)
+    except Exception as exc:
+        logger.warning(f"[modify_history] 实时写入修改留痕失败: {exc}")
+        return None
+
+
+def finalize_modify_history_for_task(
+    *,
+    project_path: Any,
+    data_dir: Any,
+    conversation_id: Optional[str],
+    msg: Dict[str, Any],
+    finished_at: Optional[str] = None,
+) -> Optional[str]:
+    """任务结束收尾：写入完成时间，并检查文件存在性。
+
+    任务结束时已不存在（被 rm/移动）的文件，其小节转为 /dev/null→最后内容 的
+    new file diff（git apply 可直接恢复）；无内容记录的标注为无法重建。
+    由 server/chat_flow_task_main.finalize_user_work_timer 调用；直接 IO，失败仅告警。
+    """
+    try:
+        metadata = msg.get("metadata") if isinstance(msg, dict) else None
+        summary = (metadata or {}).get("edit_summary")
+        if not isinstance(summary, dict):
+            return None
+        files = summary.get("files")
+        if not isinstance(files, list) or not files:
+            return None
+        if not is_modify_history_enabled(data_dir):
+            return None
+        history_dir = get_modify_history_dir(project_path, conversation_id)
+        if history_dir is None:
+            return None
+        project_root = Path(project_path).expanduser().resolve()
+
+        file_name = summary.get(_HISTORY_FILE_KEY)
+        if not isinstance(file_name, str) or not file_name.strip():
+            # 实时路径未写过（异常/旧对话）：按收尾补一次完整渲染
+            file_name = _ensure_history_file_name(msg, summary, history_dir=history_dir)
+
+        payload = _build_files_payload(files, project_root=project_root)
+        if not payload:
+            return None
+        content = render_modify_history_diff(
+            conversation_id=str(conversation_id),
+            user_message_text=_message_text(msg),
+            started_at=_task_started_at(msg),
+            finished_at=finished_at or datetime.now().isoformat(timespec="seconds"),
+            files=payload,
+        )
+        return _write_history_file(history_dir, file_name.strip(), content)
+    except Exception as exc:
+        logger.warning(f"[modify_history] 收尾写入修改留痕失败: {exc}")
+        return None
diff --git a/modules/personalization_manager.py b/modules/personalization_manager.py
index bdc377a8..6de1bebf 100644
--- a/modules/personalization_manager.py
+++ b/modules/personalization_manager.py
@@ -109,6 +109,7 @@ DEFAULT_PERSONALIZATION_CONFIG: Dict[str, Any] = {
     "quick_dock_auto_expand": True,  # 快捷窗口自动展开：True-有内容时自动展开 / False-只能手动点击按钮展开
     "file_preview_auto_wrap": False,  # 文件预览窗口自动换行：True-按面板宽度换行显示 / False-长行横向滚动
     "edit_summary_live_display": False,  # 编辑摘要卡片显示时机：False-一次工作完成后才显示（默认） / True-工作运行期间实时显示
+    "modify_history_enabled": True,  # 修改留痕：True-任务完成时把本轮净修改落盘到工作区 .astrion/modify_history/（默认开启） / False-不落盘也不注入 prompt
     "group_sidebar_by_workspace": False,  # 侧边栏按工作区/项目分组显示对话
     "sidebar_pinned_workspaces": [],  # 分组侧边栏中永久置顶的工作区ID列表
     "sidebar_workspace_order": [],  # 分组侧边栏中非置顶工作区的显示顺序
@@ -557,6 +558,12 @@ def sanitize_personalization_payload(
     else:
         base["edit_summary_live_display"] = bool(base.get("edit_summary_live_display", False))
 
+    # 修改留痕（默认开启 = 任务完成时落盘 diff 并注入 prompt）
+    if "modify_history_enabled" in data:
+        base["modify_history_enabled"] = bool(data.get("modify_history_enabled"))
+    else:
+        base["modify_history_enabled"] = bool(base.get("modify_history_enabled", True))
+
     # 侧边栏按工作区/项目分组显示对话
     if "group_sidebar_by_workspace" in data:
         base["group_sidebar_by_workspace"] = bool(data.get("group_sidebar_by_workspace"))
diff --git a/prompts/modify_history.txt b/prompts/modify_history.txt
new file mode 100644
index 00000000..806ffc89
--- /dev/null
+++ b/prompts/modify_history.txt
@@ -0,0 +1,10 @@
+## 修改留痕（Modify History）
+
+本工作区开启了修改留痕：每次你使用 write_file / edit_file 编辑文件后，系统会把本次任务的修改实时记录（unified diff，含任务说明注释）到以下目录：
+
+{modify_history_dir}
+
+该目录按对话隔离，上述路径即本对话专属目录；每次任务（一条用户输入）对应一个 .diff 文件，文件名为「该任务的用户输入（截断）+ 任务开始时间」，记录该任务全部原生编辑（write_file / edit_file）的净 +/- 修改，随每次编辑实时更新。留痕文件可直接用 `git apply`（重做）或 `git apply -R`（撤销）应用，用于版本控制缺失或被误操作（如 git checkout 覆盖）时的人工恢复；标注「已不存在」的小节为任务结束时已被删除/移动的文件，对其执行 `git apply` 可直接恢复。
+
+- 该目录由系统自动维护：不要创建、修改、移动或删除其中任何文件
+- 它不影响你的正常工作流程，无需主动向用户提及，除非用户询问修改恢复相关事宜
diff --git a/server/chat_flow_task_main.py b/server/chat_flow_task_main.py
index a87d01ce..7ce7dcdd 100644
--- a/server/chat_flow_task_main.py
+++ b/server/chat_flow_task_main.py
@@ -1638,6 +1638,19 @@ async def handle_task_with_sender(
         target_msg["metadata"] = metadata
         history[target_index] = target_msg
         web_terminal.context_manager.auto_save_conversation(force=True)
+        # 修改留痕收尾：写入完成时间；被 rm/移动的文件转为可恢复 diff（实时内容已在编辑时落盘）
+        try:
+            from modules.modify_history import finalize_modify_history_for_task
+            finalize_modify_history_for_task(
+                project_path=getattr(web_terminal, "project_path", None),
+                data_dir=getattr(web_terminal, "data_dir", None),
+                conversation_id=conversation_id,
+                msg=target_msg,
+                finished_at=timer.get("finished_at"),
+            )
+        except Exception as exc:
+            import logging
+            logging.getLogger(__name__).warning(f"[modify_history] 收尾钩子执行失败: {exc}")
         finalized_work_message_indices.add(target_index)
 
     def switch_current_work_timer_to_latest_user():
diff --git a/static/src/components/personalization/PersonalizationDrawer.vue b/static/src/components/personalization/PersonalizationDrawer.vue
index dc49a0b3..94c1938a 100644
--- a/static/src/components/personalization/PersonalizationDrawer.vue
+++ b/static/src/components/personalization/PersonalizationDrawer.vue
@@ -892,6 +892,23 @@
                             })
                           " /><FancyCheck :checked="form.agents_md_auto_inject" /></label>
 
+                      <label class="settings-toggle-row"
+                        ><span class="settings-row-copy"
+                          ><span class="settings-row-title">文件修改留痕</span
+                          ><span class="settings-row-desc"
+                            >每次任务完成后，把本轮 write/edit 的文件修改以 diff 形式保存到工作区
+                            .astrion/modify_history/，误操作（如被 git checkout 覆盖）后可据此人工恢复</span
+                          ></span
+                        ><input
+                          type="checkbox"
+                          :checked="form.modify_history_enabled"
+                          @change="
+                            personalization.updateField({
+                              key: 'modify_history_enabled',
+                              value: $event.target.checked
+                            })
+                          " /><FancyCheck :checked="form.modify_history_enabled" /></label>
+
                       <div class="settings-section-divider">
                         <span class="settings-section-divider__label">版本控制</span>
                       </div>
diff --git a/static/src/stores/personalization.ts b/static/src/stores/personalization.ts
index 149fd46c..09e763bc 100644
--- a/static/src/stores/personalization.ts
+++ b/static/src/stores/personalization.ts
@@ -34,6 +34,7 @@ interface PersonalForm {
   quick_dock_auto_expand: boolean;
   file_preview_auto_wrap: boolean;
   edit_summary_live_display: boolean;
+  modify_history_enabled: boolean;
   stacked_hide_borders: boolean;
   minimal_expand_height_limited: boolean;
   enhanced_tool_display_categories: string[];
@@ -231,6 +232,7 @@ const defaultForm = (): PersonalForm => ({
   quick_dock_auto_expand: loadCachedQuickDockAutoExpand(),
   file_preview_auto_wrap: false,
   edit_summary_live_display: false,
+  modify_history_enabled: true,
   stacked_hide_borders: loadCachedStackedHideBorders(),
   minimal_expand_height_limited: loadCachedMinimalExpandHeightLimited(),
   enhanced_tool_display_categories: [],
@@ -441,6 +443,7 @@ export const usePersonalizationStore = defineStore('personalization', {
         quick_dock_auto_expand: data.quick_dock_auto_expand !== false,
         file_preview_auto_wrap: !!data.file_preview_auto_wrap,
         edit_summary_live_display: !!data.edit_summary_live_display,
+        modify_history_enabled: data.modify_history_enabled !== false,
         stacked_hide_borders: !!data.stacked_hide_borders,
         minimal_expand_height_limited: data.minimal_expand_height_limited !== false,
         enhanced_tool_display_categories: Array.isArray(data.enhanced_tool_display_categories)