diff --git a/crates/app-iced/src/app/state/saves_shot.rs b/crates/app-iced/src/app/state/saves_shot.rs
index 3db00fb..899bb2f 100644
--- a/crates/app-iced/src/app/state/saves_shot.rs
+++ b/crates/app-iced/src/app/state/saves_shot.rs
@@ -91,6 +91,7 @@ pub fn view(instance: &str) -> unlucky_presenter::dto::SavesListView {
 /// | `rename` | 行内重命名进行中（输入框 + 改名/取消） |
 /// | `confirm` | 删除的二次确认模态框 |
 /// | `backed-up` | 备份成功的回执那句话（带落点路径与大小） |
+/// | `running` | 「游戏正在运行，先退出再操作」那条写失败（M247 的在飞闸门） |
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum Mode {
     /// 默认：列表 + 行操作区。
@@ -101,6 +102,8 @@ pub enum Mode {
     Confirm,
     /// 备份成功的回执。
     BackedUp,
+    /// 写操作被「游戏在运行」挡下。
+    Running,
 }
 
 fn mode() -> Mode {
@@ -111,6 +114,7 @@ fn mode() -> Mode {
         "rename" => Mode::Rename,
         "confirm" => Mode::Confirm,
         "backed-up" => Mode::BackedUp,
+        "running" => Mode::Running,
         _ => Mode::Plain,
     }
 }
@@ -136,6 +140,17 @@ pub fn seed(app: &mut crate::app::state::App, instance: &str) {
     };
     match mode {
         Mode::Rename => app.state.saves.start_rename(&dir),
+        // 在飞闸门那条失败（`host::saves::dispatch` 在 `running` 时直接回它）。
+        Mode::Running => app
+            .state
+            .saves
+            .failed(unlucky_presenter::dto::SavesFailureView {
+                instance: instance.to_string(),
+                file: dir,
+                op: Some(unlucky_presenter::dto::SavesFailureOp::Rename),
+                kind: unlucky_presenter::dto::SavesFailureKind::GameRunning,
+                detail: String::new(),
+            }),
         Mode::Confirm => {
             app.state.saves.ask_delete(&dir);
             let (title, body, primary, secondary) =
diff --git a/crates/app-iced/src/pages/instances/tests/saves.rs b/crates/app-iced/src/pages/instances/tests/saves.rs
index 2c29c92..a116479 100644
--- a/crates/app-iced/src/pages/instances/tests/saves.rs
+++ b/crates/app-iced/src/pages/instances/tests/saves.rs
@@ -8,12 +8,12 @@
 //! 结构断言盯着 `detail_column` 里 MODS 与 SAVES 的先后；这里守模型）。
 
 use unlucky_presenter::dto::{
-    SavesArea, SavesFailureKind, SavesFailureOp, SavesFailureView, SavesListView, SavesOped,
-    SavesSkipKind, SavesSkipView, ScreenshotView, WorldView,
+    SavesArea, SavesFailureKind, SavesFailureView, SavesListView, SavesSkipKind, SavesSkipView,
+    ScreenshotView, WorldView,
 };
-use unlucky_presenter::state::{SavesOp, SavesState};
+use unlucky_presenter::state::SavesState;
 
-use super::super::saves::{failure_line, from_state, op_line};
+use super::super::saves::{failure_line, from_state};
 use super::super::Texts;
 use unlucky_i18n::Lang;
 
@@ -214,137 +214,6 @@ fn the_failure_line_follows_the_language_and_keeps_the_detail_in_brackets() {
     assert!(!text.contains('（'), "空原文留下了一对括号：{text}");
 }
 
-/// 写操作失败：**不画重试**（重试按钮会去重新列目录，那是错的动作），并且主句带**哪个世界**。
-///
-/// 抓得住：三种写失败被折叠成同一句「读取 saves/ 失败」——用户看不出是哪一行出了什么事。
-#[test]
-fn write_failures_are_named_per_operation_and_never_retryable() {
-    let cases = [
-        (
-            SavesFailureOp::Rename,
-            SavesFailureKind::WriteConflict,
-            "重命名 Better World 失败：同名世界已存在",
-        ),
-        (
-            SavesFailureOp::Delete,
-            SavesFailureKind::WriteMissing,
-            "删除 Better World 失败：那个世界已不在",
-        ),
-        (
-            SavesFailureOp::Backup,
-            SavesFailureKind::WriteTooLarge,
-            "备份 Better World 失败：这个世界太大，一个 zip 装不下",
-        ),
-    ];
-    for (op, kind, expected) in cases {
-        let failure = SavesFailureView {
-            instance: "a".to_string(),
-            file: "Better World".to_string(),
-            op: Some(op),
-            kind,
-            detail: String::new(),
-        };
-        let line = failure_line(&failure, Texts::of(Lang::ZhCn.catalog()));
-        assert_eq!(line, expected);
-
-        let mut state = bound_state("a");
-        state.changed(view("a"));
-        state.failed(failure);
-        let saves = from_state(&state, Lang::ZhCn.catalog());
-        assert!(!saves.retryable, "{op:?} 失败了还画着重试按钮");
-        assert!(saves.error.is_some());
-        assert_eq!(saves.worlds.len(), 1, "{op:?} 失败把列表清了");
-    }
-}
-
-/// 三样交互态（草稿 / 在飞 / 回执）都要变成页面字段：改名中的那一行、置灰的那一行、成功那句话。
-#[test]
-fn draft_pending_and_receipt_become_page_fields() {
-    let mut state = bound_state("a");
-    state.changed(view("a"));
-    state.start_rename("Better World");
-    state.edit_rename("Renamed".to_string());
-    let saves = from_state(&state, Lang::En.catalog());
-    let editing = saves.editing.as_ref().expect("草稿没进页面模型");
-    assert_eq!(editing.dir, "Better World");
-    assert_eq!(editing.text, "Renamed");
-    assert!(!saves.busy_with("Better World"), "还在打字就算在飞了");
-
-    state.mark_pending(SavesOp::Backup {
-        dir: "Better World".to_string(),
-    });
-    let saves = from_state(&state, Lang::En.catalog());
-    assert!(saves.editing.is_none(), "发请求时草稿该收起来");
-    assert!(saves.busy_with("Better World"));
-    assert!(!saves.busy_with("Other"));
-
-    // 回执：host 写在快照里，下一次普通 List 就没了。
-    let mut done = view("a");
-    done.last_op = Some(SavesOped::BackedUp {
-        dir: "Better World".to_string(),
-        file: "Better World-20240501-100000.zip".to_string(),
-        path: "D:/ULL/.ULL/data/exports/saves/Better World-20240501-100000.zip".to_string(),
-        bytes: 2_048,
-        skipped: 2,
-    });
-    state.changed(done);
-    let saves = from_state(&state, Lang::ZhCn.catalog());
-    let notice = saves.notice.as_deref().expect("回执没进页面模型");
-    assert!(notice.contains("2.0 KB"), "回执要带大小：{notice}");
-    assert!(
-        notice.contains("Better World-20240501-100000.zip"),
-        "{notice}"
-    );
-    assert!(
-        notice.contains("跳过 2 个符号链接"),
-        "跳过的链接要报出来：{notice}"
-    );
-    assert!(saves.busy.is_none(), "回程之后还在飞");
-}
-
-/// 三种回执的措辞（重命名 / 删除 / 备份）。
-#[test]
-fn every_receipt_says_what_happened() {
-    let texts = Texts::of(Lang::ZhCn.catalog());
-    assert_eq!(
-        op_line(
-            &SavesOped::Renamed {
-                from: "A".to_string(),
-                to: "B".to_string()
-            },
-            texts
-        ),
-        "已把 A 改名为 B。"
-    );
-    assert_eq!(
-        op_line(
-            &SavesOped::Deleted {
-                dir: "A".to_string()
-            },
-            texts
-        ),
-        "已删除 A。"
-    );
-    let backed_up = op_line(
-        &SavesOped::BackedUp {
-            dir: "A".to_string(),
-            file: "A.zip".to_string(),
-            path: "D:/x/A.zip".to_string(),
-            bytes: 0,
-            skipped: 0,
-        },
-        texts,
-    );
-    assert!(
-        backed_up.starts_with("已把 A 备份到 D:/x/A.zip"),
-        "{backed_up}"
-    );
-    assert!(
-        !backed_up.contains("符号链接"),
-        "没跳过就别提链接：{backed_up}"
-    );
-}
-
 /// 时间换算：毫秒 → `YYYY-MM-DD HH:MM UTC`（跨年/闰日各钉一条，别只信一条）。
 #[test]
 fn millisecond_stamps_are_rendered_in_utc() {
@@ -372,3 +241,5 @@ fn millisecond_stamps_are_rendered_in_utc() {
         stamp(1_709_251_140_000)
     );
 }
+
+mod write;
diff --git a/crates/app-iced/src/pages/instances/tests/saves/write.rs b/crates/app-iced/src/pages/instances/tests/saves/write.rs
new file mode 100644
index 0000000..82a9000
--- /dev/null
+++ b/crates/app-iced/src/pages/instances/tests/saves/write.rs
@@ -0,0 +1,201 @@
+//! 存档**写操作**的页面模型判据（M247）——从 `tests/saves.rs` 拆出（那边越过 400 行）。
+//!
+//! 三条都在 `from_state` 这一层钉：写失败的主句（哪一行 + 哪个动作 + 什么原因）、
+//! 「游戏在运行」不是「写盘失败」（不留重试按钮）、以及草稿 / 在飞 / 回执变成页面字段。
+
+use super::super::super::saves::{failure_line, from_state, op_line};
+use super::super::super::Texts;
+use super::{bound_state, view};
+use unlucky_i18n::Lang;
+use unlucky_presenter::dto::{SavesFailureKind, SavesFailureOp, SavesFailureView, SavesOped};
+use unlucky_presenter::state::SavesOp;
+
+/// 写操作失败：**不画重试**（重试按钮会去重新列目录，那是错的动作），并且主句带**哪个世界**。
+///
+/// 抓得住：三种写失败被折叠成同一句「读取 saves/ 失败」——用户看不出是哪一行出了什么事。
+#[test]
+fn write_failures_are_named_per_operation_and_never_retryable() {
+    let cases = [
+        (
+            SavesFailureOp::Rename,
+            SavesFailureKind::WriteConflict,
+            "重命名 Better World 失败：同名世界已存在",
+        ),
+        (
+            SavesFailureOp::Delete,
+            SavesFailureKind::WriteMissing,
+            "删除 Better World 失败：那个世界已不在",
+        ),
+        (
+            SavesFailureOp::Backup,
+            SavesFailureKind::WriteTooLarge,
+            "备份 Better World 失败：这个世界太大，一个 zip 装不下",
+        ),
+    ];
+    for (op, kind, expected) in cases {
+        let failure = SavesFailureView {
+            instance: "a".to_string(),
+            file: "Better World".to_string(),
+            op: Some(op),
+            kind,
+            detail: String::new(),
+        };
+        let line = failure_line(&failure, Texts::of(Lang::ZhCn.catalog()));
+        assert_eq!(line, expected);
+
+        let mut state = bound_state("a");
+        state.changed(view("a"));
+        state.failed(failure);
+        let saves = from_state(&state, Lang::ZhCn.catalog());
+        assert!(!saves.retryable, "{op:?} 失败了还画着重试按钮");
+        assert!(saves.error.is_some());
+        assert_eq!(saves.worlds.len(), 1, "{op:?} 失败把列表清了");
+    }
+}
+
+/// 「游戏在跑」不是「写盘失败」：主句要直说先退出，而且**不画重试**。
+///
+/// 抓得住：把这条折进 `WriteFailed` —— 用户会看到「删除 A 失败：写盘失败」，然后以为是权限问题，
+/// 反复重试；真正该做的事（退出游戏）一个字都没说。
+#[test]
+fn a_running_game_says_exit_first_not_write_failed() {
+    let cases = [
+        (
+            SavesFailureOp::Rename,
+            "重命名 Better World 失败：游戏正在运行（先退出再操作）",
+        ),
+        (
+            SavesFailureOp::Delete,
+            "删除 Better World 失败：游戏正在运行（先退出再操作）",
+        ),
+        (
+            SavesFailureOp::Backup,
+            "备份 Better World 失败：游戏正在运行（先退出再操作）",
+        ),
+    ];
+    for (op, expected) in cases {
+        let failure = SavesFailureView {
+            instance: "a".to_string(),
+            file: "Better World".to_string(),
+            op: Some(op),
+            kind: SavesFailureKind::GameRunning,
+            detail: String::new(),
+        };
+        assert_eq!(
+            failure_line(&failure, Texts::of(Lang::ZhCn.catalog())),
+            expected
+        );
+        assert!(
+            !expected.contains("写盘失败"),
+            "「游戏在跑」被说成了「写盘失败」"
+        );
+
+        let mut state = bound_state("a");
+        state.changed(view("a"));
+        state.failed(failure);
+        let saves = from_state(&state, Lang::ZhCn.catalog());
+        assert!(!saves.retryable, "{op:?}：在飞被拒还画重试按钮");
+        assert_eq!(saves.worlds.len(), 1, "{op:?}：被拒把列表清了");
+    }
+    // 英文那一侧同一条判据（主语不同、意思相同）。
+    let failure = SavesFailureView {
+        instance: "a".to_string(),
+        file: "Better World".to_string(),
+        op: Some(SavesFailureOp::Delete),
+        kind: SavesFailureKind::GameRunning,
+        detail: String::new(),
+    };
+    let en = failure_line(&failure, Texts::of(Lang::En.catalog()));
+    assert_eq!(
+        en,
+        "Could not delete Better World: the game is running (exit it first)"
+    );
+}
+
+/// 三样交互态（草稿 / 在飞 / 回执）都要变成页面字段：改名中的那一行、置灰的那一行、成功那句话。
+#[test]
+fn draft_pending_and_receipt_become_page_fields() {
+    let mut state = bound_state("a");
+    state.changed(view("a"));
+    state.start_rename("Better World");
+    state.edit_rename("Renamed".to_string());
+    let saves = from_state(&state, Lang::En.catalog());
+    let editing = saves.editing.as_ref().expect("草稿没进页面模型");
+    assert_eq!(editing.dir, "Better World");
+    assert_eq!(editing.text, "Renamed");
+    assert!(!saves.busy_with("Better World"), "还在打字就算在飞了");
+
+    state.mark_pending(SavesOp::Backup {
+        dir: "Better World".to_string(),
+    });
+    let saves = from_state(&state, Lang::En.catalog());
+    assert!(saves.editing.is_none(), "发请求时草稿该收起来");
+    assert!(saves.busy_with("Better World"));
+    assert!(!saves.busy_with("Other"));
+
+    // 回执：host 写在快照里，下一次普通 List 就没了。
+    let mut done = view("a");
+    done.last_op = Some(SavesOped::BackedUp {
+        dir: "Better World".to_string(),
+        file: "Better World-20240501-100000.zip".to_string(),
+        path: "D:/ULL/.ULL/data/exports/saves/Better World-20240501-100000.zip".to_string(),
+        bytes: 2_048,
+        skipped: 2,
+    });
+    state.changed(done);
+    let saves = from_state(&state, Lang::ZhCn.catalog());
+    let notice = saves.notice.as_deref().expect("回执没进页面模型");
+    assert!(notice.contains("2.0 KB"), "回执要带大小：{notice}");
+    assert!(
+        notice.contains("Better World-20240501-100000.zip"),
+        "{notice}"
+    );
+    assert!(
+        notice.contains("跳过 2 个符号链接"),
+        "跳过的链接要报出来：{notice}"
+    );
+    assert!(saves.busy.is_none(), "回程之后还在飞");
+}
+
+/// 三种回执的措辞（重命名 / 删除 / 备份）。
+#[test]
+fn every_receipt_says_what_happened() {
+    let texts = Texts::of(Lang::ZhCn.catalog());
+    assert_eq!(
+        op_line(
+            &SavesOped::Renamed {
+                from: "A".to_string(),
+                to: "B".to_string()
+            },
+            texts
+        ),
+        "已把 A 改名为 B。"
+    );
+    assert_eq!(
+        op_line(
+            &SavesOped::Deleted {
+                dir: "A".to_string()
+            },
+            texts
+        ),
+        "已删除 A。"
+    );
+    let backed_up = op_line(
+        &SavesOped::BackedUp {
+            dir: "A".to_string(),
+            file: "A.zip".to_string(),
+            path: "D:/x/A.zip".to_string(),
+            bytes: 0,
+            skipped: 0,
+        },
+        texts,
+    );
+    assert!(
+        backed_up.starts_with("已把 A 备份到 D:/x/A.zip"),
+        "{backed_up}"
+    );
+    assert!(
+        !backed_up.contains("符号链接"),
+        "没跳过就别提链接：{backed_up}"
+    );
+}
diff --git a/crates/app-iced/src/pages/instances/text.rs b/crates/app-iced/src/pages/instances/text.rs
index 69ec36f..39c6cb0 100644
--- a/crates/app-iced/src/pages/instances/text.rs
+++ b/crates/app-iced/src/pages/instances/text.rs
@@ -288,6 +288,7 @@ impl Texts {
             SavesFailureKind::WriteConflict => Key::InstancesSavesReasonConflict,
             SavesFailureKind::WriteBoundary => Key::InstancesSavesReasonBoundary,
             SavesFailureKind::WriteTooLarge => Key::InstancesSavesReasonTooLarge,
+            SavesFailureKind::GameRunning => Key::InstancesSavesReasonRunning,
             SavesFailureKind::WriteFailed => Key::InstancesSavesReasonWrite,
         })
     }
diff --git a/crates/i18n/src/catalog/golden.rs b/crates/i18n/src/catalog/golden.rs
index 6d5c08f..d1e2296 100644
--- a/crates/i18n/src/catalog/golden.rs
+++ b/crates/i18n/src/catalog/golden.rs
@@ -149,6 +149,7 @@ pub(super) const GOLDEN: &[(&str, &str, &str)] = &[
     ("InstancesSavesReasonBoundary", "that path is outside saves/", "那个路径落在 saves/ 之外"),
     ("InstancesSavesReasonTooLarge", "the world is too large for one zip", "这个世界太大，一个 zip 装不下"),
     ("InstancesSavesReasonWrite", "the write failed", "写盘失败"),
+    ("InstancesSavesReasonRunning", "the game is running (exit it first)", "游戏正在运行（先退出再操作）"),
 ];
 
 /// 金表的**全量**行（本文件 → [`tail`] → [`tail_ai`] → [`tail2`]，顺序即 `Key::ALL`）。
diff --git a/crates/i18n/src/catalog/instances.rs b/crates/i18n/src/catalog/instances.rs
index 994b781..9b9ac6e 100644
--- a/crates/i18n/src/catalog/instances.rs
+++ b/crates/i18n/src/catalog/instances.rs
@@ -205,6 +205,9 @@ macro_rules! instances_entries {
             InstancesSavesReasonBoundary => ("that path is outside saves/", "那个路径落在 saves/ 之外"),
             InstancesSavesReasonTooLarge => ("the world is too large for one zip", "这个世界太大，一个 zip 装不下"),
             InstancesSavesReasonWrite => ("the write failed", "写盘失败"),
+            // 实例在启动/运行中：三个写操作**主动不写盘**（不是"写盘失败"——Linux 上删一个正在跑的
+            // 世界是会成功的，所以这条要直说"先退出"，别让用户以为是权限问题）。
+            InstancesSavesReasonRunning => ("the game is running (exit it first)", "游戏正在运行（先退出再操作）"),
         } }
     };
 }
diff --git a/crates/presenter/src/dto/saves.rs b/crates/presenter/src/dto/saves.rs
index 5afc71f..7f27c6a 100644
--- a/crates/presenter/src/dto/saves.rs
+++ b/crates/presenter/src/dto/saves.rs
@@ -284,6 +284,11 @@ pub enum SavesFailureKind {
     WriteBoundary,
     /// 写操作：备份超过体积或条目上限。
     WriteTooLarge,
+    /// 写操作：实例正在启动/运行中，**一个字节都没碰盘**（见 `host::saves::dispatch`）。
+    ///
+    /// 单独一类而不是折进 [`WriteFailed`](Self::WriteFailed)：Linux 上删一个正在跑的世界**会成功**，
+    /// 所以这不是"写盘失败了"，是"我们主动没写"。界面必须说「游戏正在运行，先退出再操作」。
+    GameRunning,
     /// 写操作：其它系统错误（权限 / 被别的进程占用），OS 原文进 `detail`。
     WriteFailed,
 }
diff --git a/crates/presenter/src/host/dispatch.rs b/crates/presenter/src/host/dispatch.rs
index 4003211..8d06f5d 100644
--- a/crates/presenter/src/host/dispatch.rs
+++ b/crates/presenter/src/host/dispatch.rs
@@ -290,10 +290,17 @@ impl CoreHost {
                 let running = self.in_flight(&id);
                 mods::dispatch(self.env.clone(), self.tx.clone(), *command, running);
             }
-            // M235：实例存档 / 截图的只读列表 + 打开文件夹
-            // （只读，所以不必问"游戏在不在跑"；拉起文件管理器在 core 的 platform opener 里）
+            // M235：实例存档 / 截图的只读列表 + 打开文件夹；M247 加了三个写操作。
+            //
+            // **写操作要看"游戏在不在跑"**（M247 补齐，与 `AppCommand::Mods` 同款判据）：
+            // Windows 上进程占着世界目录 ⇒ rename/删除会撞共享冲突；**Linux 上删一个正在跑的世界
+            // 会成功**——那是在用户正在玩的时候把存档删掉。所以判据放在 host 这一侧、落 core 之前，
+            // 在飞就回一条结构化失败「游戏正在运行，先退出再操作」，一个字节都不碰盘。
+            // 读路径与「打开文件夹」不受影响（它们不改盘）。
             AppCommand::Saves(command) => {
-                saves::dispatch(self.env.clone(), self.tx.clone(), *command);
+                let id = saves::instance_of(&command).to_string();
+                let running = self.in_flight(&id);
+                saves::dispatch(self.env.clone(), self.tx.clone(), *command, running);
             }
             // AI 对话：agent 的 GUI host 未落地前用脚本回复（不接真实模型）
             other @ (AppCommand::AskAgent(_) | AppCommand::StopAgent | AppCommand::SetYolo(_)) => {
diff --git a/crates/presenter/src/host/saves.rs b/crates/presenter/src/host/saves.rs
index faa71d5..13e9521 100644
--- a/crates/presenter/src/host/saves.rs
+++ b/crates/presenter/src/host/saves.rs
@@ -8,6 +8,7 @@
 //! | 单根语义（D20） | 运行目录来自 `game::isolation::derive_game_dir`——**与启动同一个答案**，不另派生、不做双根合并 |
 //! | 读路径只读 | [`list`] 一次写盘都没有；`saves/` 不存在也不替玩家建（core 的 `saves::scan` 同理） |
 //! | 写路径自己重校边界 | 三个写操作**不在 host 这边信任自己**：core 的 `saves::write` 每次重新校验 `run_dir` 与目标路径（越界 / 符号链接 / 撞名都在那里拒） |
+//! | 游戏在跑就不写 | [`dispatch`] 的 `running` 为真时三条写命令**不 spawn、不碰盘**，直接回 [`crate::dto::SavesFailureKind::GameRunning`] |
 //!
 //! ## 三个写操作的回程形状
 //!
@@ -20,6 +21,22 @@
 //! **写成功后一律重新列一遍**（`snapshot`）：界面画的永远是磁盘上的真相，不是"我以为我改成了什么"。
 //! 回执只是"这次动的是哪一条"，与快照一起回去，所以 UI 不会出现「列表变了但不知道谁变的」。
 //!
+//! ## 「游戏在跑」为什么挡在 host 这一侧（M247）
+//!
+//! 判据是 `CoreHost::in_flight(&id)`（与 `AppCommand::Mods` 同一个），由 `host::dispatch` 传进来。
+//! 为真时 [`dispatch`] **不 spawn 线程**、直接发一条 [`SavesFailureKind::GameRunning`] 的失败回去：
+//!
+//! | 平台 | 不挡的后果 |
+//! |---|---|
+//! | Windows | 进程占着世界目录 ⇒ rename/删除撞共享冲突 ⇒ 用户读一句 `os error 32` |
+//! | **Linux** | **删一个正在跑的世界会成功** —— 用户在玩到一半时丢了存档 |
+//!
+//! 所以这不是"说得更清楚"，是**安全性**。也不能只靠界面灰按钮：判据留在 host，UI 那一侧只是
+//! 尽力而为的提示（本版没加"灰按钮"的形态，理由是快照里没有 `running` 字段——加它要动列表 DTO，
+//! 而这一版已经有那条明确的失败句子兜住）。
+//!
+//! 读路径（[`SavesCommand::List`]）与「打开文件夹」**不受影响**：它们不改盘。
+
 //! ## 为什么不复用启动路径的 `run_dir()`
 //!
 //! 与 [`super::mods`] 同一条理由：`host::launch` 的 `run_dir()` 顺带把「这次用哪个档位」写进实例
@@ -51,7 +68,7 @@ use std::path::PathBuf;
 
 use unlucky_core::game::install::instance::read_instance_config;
 use unlucky_core::game::isolation::derive_game_dir;
-use unlucky_core::game::saves::{self, SavesError, SavesScan, SavesWriteError, SavesWriteKind};
+use unlucky_core::game::saves::{self, SavesError, SavesScan};
 use unlucky_core::platform::opener;
 
 use crate::dto::{
@@ -63,6 +80,8 @@ use crate::dto::{
 use super::env::HostEnv;
 use super::job::{spawn, JobSender};
 
+mod write;
+
 /// 后台线程回报的一次结果（`HostTask::Saves` 的载荷）。
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Report {
@@ -97,54 +116,68 @@ pub fn spawn_open_folder(env: HostEnv, tx: JobSender, id: InstanceId) {
     });
 }
 
-/// 一条指令 → 后台线程（`CoreHost::dispatch` 的唯一入口）。
-pub fn dispatch(env: HostEnv, tx: JobSender, command: SavesCommand) {
+/// 一条指令属于哪个实例（host 侧算「游戏在不在跑」要用它）。
+///
+/// 五条命令都带实例 id，所以这里不返回 `Option`：少一条分支处理会让闸门在那条命令上
+/// **静默失效**，而这正是 M247 要修的东西。
+#[must_use]
+pub fn instance_of(command: &SavesCommand) -> &str {
     match command {
-        SavesCommand::List(id) => spawn_list(env, tx, id),
-        SavesCommand::OpenFolder { id } => spawn_open_folder(env, tx, id),
-        SavesCommand::RenameWorld { id, dir, to } => spawn_rename(env, tx, id, dir, to),
-        SavesCommand::DeleteWorld { id, dir } => spawn_delete(env, tx, id, dir),
-        SavesCommand::BackupWorld { id, dir, dest } => spawn_backup(env, tx, id, dir, dest),
+        SavesCommand::List(id)
+        | SavesCommand::OpenFolder { id }
+        | SavesCommand::RenameWorld { id, .. }
+        | SavesCommand::DeleteWorld { id, .. }
+        | SavesCommand::BackupWorld { id, .. } => id,
     }
 }
 
-/// 后台重命名一个世界，**并把刷新后的快照与回执一起带回来**。
-pub fn spawn_rename(env: HostEnv, tx: JobSender, id: InstanceId, dir: String, to: String) {
-    spawn("saves-rename", move || {
-        let report = Report {
-            instance: id.clone(),
-            list: rename(&env, &id, &dir, &to),
-        };
-        let _ = tx.send(super::HostTask::Saves(Box::new(report)));
-    });
+/// 这条命令是不是**改盘**的写操作（读路径与打开文件夹不是）。
+fn write_target(command: &SavesCommand) -> Option<(&str, SavesFailureOp)> {
+    match command {
+        SavesCommand::RenameWorld { dir, .. } => Some((dir, SavesFailureOp::Rename)),
+        SavesCommand::DeleteWorld { dir, .. } => Some((dir, SavesFailureOp::Delete)),
+        SavesCommand::BackupWorld { dir, .. } => Some((dir, SavesFailureOp::Backup)),
+        SavesCommand::List(_) | SavesCommand::OpenFolder { .. } => None,
+    }
 }
 
-/// 后台删除一个世界（**UI 已经二次确认过**；host 侧照样重新过边界校验）。
-pub fn spawn_delete(env: HostEnv, tx: JobSender, id: InstanceId, dir: String) {
-    spawn("saves-delete", move || {
-        let report = Report {
-            instance: id.clone(),
-            list: delete(&env, &id, &dir),
-        };
-        let _ = tx.send(super::HostTask::Saves(Box::new(report)));
-    });
+/// 一条指令 → 后台线程（`CoreHost::dispatch` 的唯一入口）。
+///
+/// `running` = 这个实例正在启动/运行中（`CoreHost::in_flight`）。为真时**三个写操作不落 core**：
+/// 直接回一条 [`SavesFailureKind::GameRunning`] 的具名失败，一个字节都不碰盘。
+///
+/// 为什么这一层必须挡：Windows 上进程占着世界目录，rename/删除会撞共享冲突（难看但至少失败）；
+/// **Linux 上删一个正在跑的世界会成功**——那是在用户玩到一半时把存档删掉。所以判据不能只靠
+/// 界面灰按钮（那也是同一条纪律：`ModsCommand::SetEnabled` 同样挡在 host 这一侧）。
+///
+/// 不 spawn 线程：没有磁盘工作要排队，直接发一条结果回去更诚实（`tx` 是同步通道）。
+pub fn dispatch(env: HostEnv, tx: JobSender, command: SavesCommand, running: bool) {
+    if running {
+        if let Some((dir, op)) = write_target(&command) {
+            let id = instance_of(&command);
+            let report = Report {
+                instance: id.to_string(),
+                list: Err(blocked(id, dir, op)),
+            };
+            let _ = tx.send(super::HostTask::Saves(Box::new(report)));
+            return;
+        }
+    }
+    match command {
+        SavesCommand::List(id) => spawn_list(env, tx, id),
+        SavesCommand::OpenFolder { id } => spawn_open_folder(env, tx, id),
+        SavesCommand::RenameWorld { id, dir, to } => write::spawn_rename(env, tx, id, dir, to),
+        SavesCommand::DeleteWorld { id, dir } => write::spawn_delete(env, tx, id, dir),
+        SavesCommand::BackupWorld { id, dir, dest } => write::spawn_backup(env, tx, id, dir, dest),
+    }
 }
 
-/// 后台把一个世界备份成 zip（落点见 [`export_dir`]），并带回新快照。
-pub fn spawn_backup(
-    env: HostEnv,
-    tx: JobSender,
-    id: InstanceId,
-    dir: String,
-    dest: Option<String>,
-) {
-    spawn("saves-backup", move || {
-        let report = Report {
-            instance: id.clone(),
-            list: backup(&env, &id, &dir, dest.as_deref()),
-        };
-        let _ = tx.send(super::HostTask::Saves(Box::new(report)));
-    });
+/// 写操作被「游戏在跑」挡下时的那条失败（**结构化，带世界名与操作**，文案由 app 层现求）。
+fn blocked(instance: &str, dir: &str, op: SavesFailureOp) -> SavesFailureView {
+    let mut failure = failure(instance, SavesFailureKind::GameRunning, String::new());
+    failure.file = dir.to_string();
+    failure.op = Some(op);
+    failure
 }
 
 /// 列目录（后台线程里调）。
@@ -156,7 +189,7 @@ fn list(env: &HostEnv, id: &str) -> Result<SavesListView, SavesFailureView> {
 /// 重新扫一遍目录 → 快照（可挂一条写操作的回执）。
 ///
 /// 写成功后**一律**走这里：界面画的是磁盘上的真相，不是"我以为我改成了什么"。
-fn snapshot(
+pub(super) fn snapshot(
     instance: &InstanceSummary,
     run_dir: &std::path::Path,
     last_op: Option<SavesOped>,
@@ -165,74 +198,6 @@ fn snapshot(
     Ok(view(&instance.id, &scan, last_op))
 }
 
-/// 重命名 → 再列一遍（回执里记「谁改成了什么」）。
-fn rename(
-    env: &HostEnv,
-    id: &str,
-    from: &str,
-    to: &str,
-) -> Result<SavesListView, SavesFailureView> {
-    let (instance, run_dir) = target(env, id)?;
-    saves::rename_world(&run_dir, from, to)
-        .map_err(|error| write_failure(&instance.id, SavesFailureOp::Rename, from, &error))?;
-    snapshot(
-        &instance,
-        &run_dir,
-        Some(SavesOped::Renamed {
-            from: from.to_string(),
-            to: to.to_string(),
-        }),
-    )
-}
-
-/// 删除 → 再列一遍（回执里记被删掉的那个名字）。
-fn delete(env: &HostEnv, id: &str, dir: &str) -> Result<SavesListView, SavesFailureView> {
-    let (instance, run_dir) = target(env, id)?;
-    saves::delete_world(&run_dir, dir)
-        .map_err(|error| write_failure(&instance.id, SavesFailureOp::Delete, dir, &error))?;
-    snapshot(
-        &instance,
-        &run_dir,
-        Some(SavesOped::Deleted {
-            dir: dir.to_string(),
-        }),
-    )
-}
-
-/// 备份 → 再列一遍（回执里记落点路径 / 字节数 / 被跳过的链接数）。
-fn backup(
-    env: &HostEnv,
-    id: &str,
-    dir: &str,
-    dest: Option<&str>,
-) -> Result<SavesListView, SavesFailureView> {
-    let (instance, run_dir) = target(env, id)?;
-    let dest = dest.map_or_else(|| export_dir(env), PathBuf::from);
-    let done = saves::backup_world(&run_dir, dir, &dest)
-        .map_err(|error| write_failure(&instance.id, SavesFailureOp::Backup, dir, &error))?;
-    let file = done
-        .path
-        .file_name()
-        .map(|name| name.to_string_lossy().into_owned())
-        .unwrap_or_default();
-    snapshot(
-        &instance,
-        &run_dir,
-        Some(SavesOped::BackedUp {
-            dir: dir.to_string(),
-            file,
-            path: done.path.display().to_string(),
-            bytes: done.bytes,
-            skipped: done.skipped,
-        }),
-    )
-}
-
-/// 备份的默认落点：`<data>/exports/saves/`（见模块文档「备份落点」一节）。
-fn export_dir(env: &HostEnv) -> PathBuf {
-    env.layout.data().join("exports").join("saves")
-}
-
 /// 打开存档目录 → 再列一遍（失败只说"打不开"，原文进括号）。
 fn open_folder(env: &HostEnv, id: &str) -> Result<SavesListView, SavesFailureView> {
     let (instance, run_dir) = target(env, id)?;
@@ -255,7 +220,10 @@ fn open_target(scan: &SavesScan, run_dir: &std::path::Path) -> PathBuf {
 }
 
 /// 实例 + 它的运行目录（找不到实例 / 派生不出目录都给具名失败）。
-fn target(env: &HostEnv, id: &str) -> Result<(InstanceSummary, PathBuf), SavesFailureView> {
+pub(super) fn target(
+    env: &HostEnv,
+    id: &str,
+) -> Result<(InstanceSummary, PathBuf), SavesFailureView> {
     let instances = super::game::instances(env);
     let Some(instance) = locate(&instances, id) else {
         return Err(failure(
@@ -270,7 +238,7 @@ fn target(env: &HostEnv, id: &str) -> Result<(InstanceSummary, PathBuf), SavesFa
 }
 
 /// 实例的运行目录（D20 覆盖链，与启动同一份派生；**不写盘**）。
-fn run_dir(env: &HostEnv, instance: &InstanceSummary) -> Result<PathBuf, String> {
+pub(super) fn run_dir(env: &HostEnv, instance: &InstanceSummary) -> Result<PathBuf, String> {
     let global = super::game::global_mode(env);
     let config = read_instance_config(&env.layout, &instance.id)
         .map_err(|error| format!("读实例设置失败：{error}"))?;
@@ -334,7 +302,11 @@ fn view(instance: &str, scan: &SavesScan, last_op: Option<SavesOped>) -> SavesLi
     }
 }
 
-fn failure(instance: &str, kind: SavesFailureKind, detail: impl Into<String>) -> SavesFailureView {
+pub(super) fn failure(
+    instance: &str,
+    kind: SavesFailureKind,
+    detail: impl Into<String>,
+) -> SavesFailureView {
     SavesFailureView {
         instance: instance.to_string(),
         file: String::new(),
@@ -353,34 +325,5 @@ fn unusable(instance: &str, error: &SavesError) -> SavesFailureView {
     )
 }
 
-/// core 的写失败 → 具名类别 + 「路径：原文」（**不翻译**，翻译在 app 层）。
-///
-/// 八个类别一一对应，没有一个落到「未知」兜底里：兜底会变成静默（用户只看到"失败了"）。
-fn write_failure(
-    instance: &str,
-    op: SavesFailureOp,
-    file: &str,
-    error: &SavesWriteError,
-) -> SavesFailureView {
-    let kind = match error.kind {
-        SavesWriteKind::UnsafeName => SavesFailureKind::WriteUnsafeName,
-        SavesWriteKind::SymbolicLink => SavesFailureKind::WriteSymlink,
-        SavesWriteKind::NotFound => SavesFailureKind::WriteMissing,
-        SavesWriteKind::NotADirectory => SavesFailureKind::WriteNotADirectory,
-        SavesWriteKind::Conflict => SavesFailureKind::WriteConflict,
-        SavesWriteKind::Boundary => SavesFailureKind::WriteBoundary,
-        SavesWriteKind::TooLarge => SavesFailureKind::WriteTooLarge,
-        SavesWriteKind::Io => SavesFailureKind::WriteFailed,
-    };
-    let mut failure = failure(
-        instance,
-        kind,
-        format!("{}：{}", error.path.display(), error.detail),
-    );
-    failure.file = file.to_string();
-    failure.op = Some(op);
-    failure
-}
-
 #[cfg(test)]
 mod tests;
diff --git a/crates/presenter/src/host/saves/tests.rs b/crates/presenter/src/host/saves/tests.rs
index 5a0307d..3d4c1a8 100644
--- a/crates/presenter/src/host/saves/tests.rs
+++ b/crates/presenter/src/host/saves/tests.rs
@@ -6,6 +6,10 @@
 //! 抓不住什么：`OpenFolder` **不在这里真跑**（它会拉起用户的文件管理器）；它唯一的判断
 //! （打开哪个目录）由 [`open_target_degrades_from_saves_to_run_dir`] 这条纯函数用例钉住，
 //! 真正 spawn 的那一步在 core 的 `platform::opener` 用例里。
+//!
+//! 「游戏在跑就拒」（M247）由 [`write_commands_do_not_touch_the_disk_while_the_game_is_running`]
+//! 从 **`dispatch` 那一层**验：三条写命令一条都不落 core（盘上指纹前后一致 + 备份落点没被建），
+//! 并且回一条 `GameRunning` 的具名失败。
 
 use super::*;
 use crate::dto::{InstanceRuntime, LaunchArgsView, LoaderInfo, LoaderKind};
@@ -204,175 +208,40 @@ fn every_core_skip_reason_keeps_its_own_kind() {
     }
 }
 
-/// **端到端**：重命名 → 真盘改名 + 新快照 + 回执。
-///
-/// 抓得住：host 用错运行目录、写完成却忘了重新列（界面还画旧名字）、回执与快照对不上。
-#[test]
-fn rename_round_trips_on_a_real_root() {
-    let (_root, env, run) = fixture("saves-rename");
-    world(&run, "Old World");
-    world(&run, "Other");
-
-    let listed = rename(&env, ID, "Old World", "New World").expect("改名");
-    assert!(!run.join("saves/Old World").exists(), "旧目录还在");
-    assert!(
-        run.join("saves/New World/level.dat").exists(),
-        "新目录里没有内容"
-    );
-    let names: Vec<&str> = listed
-        .worlds
-        .iter()
-        .map(|world| world.dir.as_str())
-        .collect();
-    assert_eq!(names, ["New World", "Other"], "快照没跟着刷新");
-    assert_eq!(
-        listed.last_op,
-        Some(SavesOped::Renamed {
-            from: "Old World".to_string(),
-            to: "New World".to_string()
-        })
-    );
-}
-
-/// **端到端**：删除 → 真盘没了 + 新快照 + 回执。
-#[test]
-fn delete_round_trips_on_a_real_root() {
-    let (_root, env, run) = fixture("saves-delete");
-    world(&run, "Doomed");
-    world(&run, "Kept");
-
-    let listed = delete(&env, ID, "Doomed").expect("删除");
-    assert!(!run.join("saves/Doomed").exists(), "目录还在");
-    let names: Vec<&str> = listed
-        .worlds
-        .iter()
-        .map(|world| world.dir.as_str())
-        .collect();
-    assert_eq!(names, ["Kept"], "别的世界被连带删了 / 快照没刷新");
-    assert_eq!(
-        listed.last_op,
-        Some(SavesOped::Deleted {
-            dir: "Doomed".to_string()
-        })
-    );
-}
-
-/// **端到端**：备份 → zip 落在启动器自己的 `exports/saves/`，回执带路径与字节数。
-#[test]
-fn backup_round_trips_to_the_exports_dir() {
-    let (_root, env, run) = fixture("saves-backup");
-    world(&run, "My World");
-
-    let listed = backup(&env, ID, "My World", None).expect("备份");
-    let exports = env.layout.data().join("exports").join("saves");
-    let Some(SavesOped::BackedUp {
-        dir,
-        file,
-        path,
-        bytes,
-        skipped,
-    }) = listed.last_op.clone()
-    else {
-        panic!("备份成功却没有回执：{:?}", listed.last_op);
-    };
-    assert_eq!(dir, "My World");
-    assert!(
-        file.starts_with("My World-"),
-        "文件名要带世界名与时戳：{file}"
-    );
-    assert!(file.ends_with(".zip"), "文件名要带 .zip：{file}");
-    assert_eq!(std::path::PathBuf::from(&path), exports.join(&file));
-    assert!(std::path::Path::new(&path).exists(), "zip 没真的落盘");
-    assert!(bytes > 0);
-    assert_eq!(skipped, 0);
-    // 备份不改世界本身：列表还是一行。
-    assert_eq!(listed.world_count(), 1);
-    // 显式落点也要照用（将来接了目录选择框就走这条）。
-    let custom = backup(
-        &env,
-        ID,
-        "My World",
-        Some(&run.join("elsewhere").display().to_string()),
-    )
-    .expect("备份到指定目录");
-    assert!(matches!(custom.last_op, Some(SavesOped::BackedUp { .. })));
-    assert!(run.join("elsewhere").is_dir(), "显式落点没被采用");
-}
-
-/// 八种写失败各给**自己的**类别（没有一个落到「未知」兜底）。
-#[test]
-fn every_write_failure_keeps_its_own_kind() {
-    let (_root, env, run) = fixture("saves-write-kinds");
-    world(&run, "Taken");
-    world(&run, "Other");
-
-    let cases = [
-        ("Other", "Taken", SavesFailureKind::WriteConflict),
-        ("Other", "..", SavesFailureKind::WriteUnsafeName),
-        ("Nope", "Fresh", SavesFailureKind::WriteMissing),
-    ];
-    for (from, to, expected) in cases {
-        let failure = rename(&env, ID, from, to).expect_err("改成功了");
-        assert_eq!(failure.kind, expected, "{from} → {to}：{}", failure.detail);
-    }
-
-    let failure = delete(&env, ID, "Nope").expect_err("删成功了");
-    assert_eq!(failure.kind, SavesFailureKind::WriteMissing);
-    // 空 / 相对的落点目录：会落到进程当前目录，所以是"越界"而不是"IO 失败"。
-    let failure = backup(&env, ID, "Taken", Some("")).expect_err("备份到空目录居然成功了");
-    assert_eq!(
-        failure.kind,
-        SavesFailureKind::WriteBoundary,
-        "{}",
-        failure.detail
-    );
-
-    // core 的八个类别 → DTO 八个类别（一一对应，不折叠）。
-    let pairs = [
-        (
-            SavesWriteKind::UnsafeName,
-            SavesFailureKind::WriteUnsafeName,
-        ),
-        (SavesWriteKind::SymbolicLink, SavesFailureKind::WriteSymlink),
-        (SavesWriteKind::NotFound, SavesFailureKind::WriteMissing),
-        (
-            SavesWriteKind::NotADirectory,
-            SavesFailureKind::WriteNotADirectory,
-        ),
-        (SavesWriteKind::Conflict, SavesFailureKind::WriteConflict),
-        (SavesWriteKind::Boundary, SavesFailureKind::WriteBoundary),
-        (SavesWriteKind::TooLarge, SavesFailureKind::WriteTooLarge),
-        (SavesWriteKind::Io, SavesFailureKind::WriteFailed),
-    ];
-    for (core, expected) in pairs {
-        let error = SavesWriteError {
-            path: PathBuf::from("C:/mc/saves/x"),
-            kind: core,
-            detail: "原文".to_string(),
+/// `(相对路径, 是否目录, 字节数, mtime 毫秒)` 的排序列表：「这一拍有没有写盘」的判据本体。
+fn fingerprint(root: &std::path::Path) -> Vec<String> {
+    let mut out = Vec::new();
+    let mut stack = vec![root.to_path_buf()];
+    while let Some(dir) = stack.pop() {
+        let Ok(read) = std::fs::read_dir(&dir) else {
+            continue;
         };
-        let failure = write_failure(ID, SavesFailureOp::Backup, "Taken", &error);
-        assert_eq!(failure.kind, expected, "{core:?}");
-        assert!(
-            failure.detail.contains("saves"),
-            "原文丢了：{}",
-            failure.detail
-        );
-        assert_eq!(failure.instance, ID);
-        assert_eq!(failure.file, "Taken", "失败那句话要指名是哪一行");
-        assert_eq!(failure.op, Some(SavesFailureOp::Backup));
+        for entry in read.flatten() {
+            let path = entry.path();
+            let Ok(meta) = std::fs::symlink_metadata(&path) else {
+                continue;
+            };
+            let rel = path
+                .strip_prefix(root)
+                .unwrap_or(&path)
+                .display()
+                .to_string();
+            out.push(format!(
+                "{rel}|dir={}|len={}|mtime={}",
+                meta.is_dir(),
+                meta.len(),
+                meta.modified()
+                    .ok()
+                    .and_then(|time| time.duration_since(std::time::SystemTime::UNIX_EPOCH).ok())
+                    .map_or(0, |since| since.as_millis())
+            ));
+            if meta.is_dir() {
+                stack.push(path);
+            }
+        }
     }
+    out.sort();
+    out
 }
 
-/// 找不到实例的写操作 ⇒ 同一个具名失败（不是"写成功了个空的"）。
-#[test]
-fn write_ops_on_a_vanished_instance_are_named() {
-    let (_root, env, _run) = fixture("saves-write-unknown");
-    for failure in [
-        rename(&env, "gone", "A", "B").expect_err("改名成功了"),
-        delete(&env, "gone", "A").expect_err("删除成功了"),
-        backup(&env, "gone", "A", None).expect_err("备份成功了"),
-    ] {
-        assert_eq!(failure.kind, SavesFailureKind::InstanceUnavailable);
-        assert_eq!(failure.instance, "gone");
-    }
-}
+mod write;
diff --git a/crates/presenter/src/host/saves/tests/write.rs b/crates/presenter/src/host/saves/tests/write.rs
new file mode 100644
index 0000000..a45621e
--- /dev/null
+++ b/crates/presenter/src/host/saves/tests/write.rs
@@ -0,0 +1,341 @@
+//! 三个**写操作**与「游戏在跑」闸门的用例（M247）——从 `host/saves/tests.rs` 拆出
+//! （那边加完 7 条之后越过 400 行硬线；判据一条不改）。
+//!
+//! | 用例 | 抓得住 |
+//! |---|---|
+//! | [`rename_round_trips_on_a_real_root`] / [`delete_round_trips_on_a_real_root`] | 真盘改动 + 快照刷新 + 回执对得上 |
+//! | [`backup_round_trips_to_the_exports_dir`] | zip 落到 `<data>/exports/saves/`，回执带路径/字节/跳过数；显式落点也照用 |
+//! | [`every_write_failure_keeps_its_own_kind`] | core 八类 → DTO 八类一一对应（不折叠），带世界名与操作 |
+//! | [`write_commands_do_not_touch_the_disk_while_the_game_is_running`] | **在飞时一条都不落 core**：盘上指纹不变、世界还在、备份落点没建、回 `GameRunning` |
+//! | [`write_commands_run_when_the_game_is_not_running`] | 闸门没有把写操作一并关死 |
+//! | [`read_commands_are_not_blocked_while_the_game_is_running`] | 读路径与打开文件夹不受影响 |
+//! | [`every_command_names_its_instance`] | 五条命令都答得上「哪个实例」（闸门靠它算在不在跑） |
+
+use super::super::write::{backup, delete, rename, write_failure};
+use super::super::*;
+use super::{fingerprint, fixture, world, ID};
+use crate::dto::{SavesCommand, SavesFailureOp, SavesFailureView, SavesOped};
+use unlucky_core::game::saves::SavesWriteKind;
+
+/// **端到端**：重命名 → 真盘改名 + 新快照 + 回执。
+///
+/// 抓得住：host 用错运行目录、写完成却忘了重新列（界面还画旧名字）、回执与快照对不上。
+#[test]
+fn rename_round_trips_on_a_real_root() {
+    let (_root, env, run) = fixture("saves-rename");
+    world(&run, "Old World");
+    world(&run, "Other");
+
+    let listed = rename(&env, ID, "Old World", "New World").expect("改名");
+    assert!(!run.join("saves/Old World").exists(), "旧目录还在");
+    assert!(
+        run.join("saves/New World/level.dat").exists(),
+        "新目录里没有内容"
+    );
+    let names: Vec<&str> = listed
+        .worlds
+        .iter()
+        .map(|world| world.dir.as_str())
+        .collect();
+    assert_eq!(names, ["New World", "Other"], "快照没跟着刷新");
+    assert_eq!(
+        listed.last_op,
+        Some(SavesOped::Renamed {
+            from: "Old World".to_string(),
+            to: "New World".to_string()
+        })
+    );
+}
+
+/// **端到端**：删除 → 真盘没了 + 新快照 + 回执。
+#[test]
+fn delete_round_trips_on_a_real_root() {
+    let (_root, env, run) = fixture("saves-delete");
+    world(&run, "Doomed");
+    world(&run, "Kept");
+
+    let listed = delete(&env, ID, "Doomed").expect("删除");
+    assert!(!run.join("saves/Doomed").exists(), "目录还在");
+    let names: Vec<&str> = listed
+        .worlds
+        .iter()
+        .map(|world| world.dir.as_str())
+        .collect();
+    assert_eq!(names, ["Kept"], "别的世界被连带删了 / 快照没刷新");
+    assert_eq!(
+        listed.last_op,
+        Some(SavesOped::Deleted {
+            dir: "Doomed".to_string()
+        })
+    );
+}
+
+/// **端到端**：备份 → zip 落在启动器自己的 `exports/saves/`，回执带路径与字节数。
+#[test]
+fn backup_round_trips_to_the_exports_dir() {
+    let (_root, env, run) = fixture("saves-backup");
+    world(&run, "My World");
+
+    let listed = backup(&env, ID, "My World", None).expect("备份");
+    let exports = env.layout.data().join("exports").join("saves");
+    let Some(SavesOped::BackedUp {
+        dir,
+        file,
+        path,
+        bytes,
+        skipped,
+    }) = listed.last_op.clone()
+    else {
+        panic!("备份成功却没有回执：{:?}", listed.last_op);
+    };
+    assert_eq!(dir, "My World");
+    assert!(
+        file.starts_with("My World-"),
+        "文件名要带世界名与时戳：{file}"
+    );
+    assert!(file.ends_with(".zip"), "文件名要带 .zip：{file}");
+    assert_eq!(std::path::PathBuf::from(&path), exports.join(&file));
+    assert!(std::path::Path::new(&path).exists(), "zip 没真的落盘");
+    assert!(bytes > 0);
+    assert_eq!(skipped, 0);
+    // 备份不改世界本身：列表还是一行。
+    assert_eq!(listed.world_count(), 1);
+    // 显式落点也要照用（将来接了目录选择框就走这条）。
+    let custom = backup(
+        &env,
+        ID,
+        "My World",
+        Some(&run.join("elsewhere").display().to_string()),
+    )
+    .expect("备份到指定目录");
+    assert!(matches!(custom.last_op, Some(SavesOped::BackedUp { .. })));
+    assert!(run.join("elsewhere").is_dir(), "显式落点没被采用");
+}
+
+/// 八种写失败各给**自己的**类别（没有一个落到「未知」兜底）。
+#[test]
+fn every_write_failure_keeps_its_own_kind() {
+    let (_root, env, run) = fixture("saves-write-kinds");
+    world(&run, "Taken");
+    world(&run, "Other");
+
+    let cases = [
+        ("Other", "Taken", SavesFailureKind::WriteConflict),
+        ("Other", "..", SavesFailureKind::WriteUnsafeName),
+        ("Nope", "Fresh", SavesFailureKind::WriteMissing),
+    ];
+    for (from, to, expected) in cases {
+        let failure = rename(&env, ID, from, to).expect_err("改成功了");
+        assert_eq!(failure.kind, expected, "{from} → {to}：{}", failure.detail);
+    }
+
+    let failure = delete(&env, ID, "Nope").expect_err("删成功了");
+    assert_eq!(failure.kind, SavesFailureKind::WriteMissing);
+    // 空 / 相对的落点目录：会落到进程当前目录，所以是「越界」而不是「IO 失败」。
+    let failure = backup(&env, ID, "Taken", Some("")).expect_err("备份到空目录居然成功了");
+    assert_eq!(
+        failure.kind,
+        SavesFailureKind::WriteBoundary,
+        "{}",
+        failure.detail
+    );
+
+    // core 的八个类别 → DTO 八个类别（一一对应，不折叠）。
+    let pairs = [
+        (
+            SavesWriteKind::UnsafeName,
+            SavesFailureKind::WriteUnsafeName,
+        ),
+        (SavesWriteKind::SymbolicLink, SavesFailureKind::WriteSymlink),
+        (SavesWriteKind::NotFound, SavesFailureKind::WriteMissing),
+        (
+            SavesWriteKind::NotADirectory,
+            SavesFailureKind::WriteNotADirectory,
+        ),
+        (SavesWriteKind::Conflict, SavesFailureKind::WriteConflict),
+        (SavesWriteKind::Boundary, SavesFailureKind::WriteBoundary),
+        (SavesWriteKind::TooLarge, SavesFailureKind::WriteTooLarge),
+        (SavesWriteKind::Io, SavesFailureKind::WriteFailed),
+    ];
+    for (core, expected) in pairs {
+        let error = unlucky_core::game::saves::SavesWriteError {
+            path: PathBuf::from("C:/mc/saves/x"),
+            kind: core,
+            detail: "原文".to_string(),
+        };
+        let failure = write_failure(ID, SavesFailureOp::Backup, "Taken", &error);
+        assert_eq!(failure.kind, expected, "{core:?}");
+        assert!(
+            failure.detail.contains("saves"),
+            "原文丢了：{}",
+            failure.detail
+        );
+        assert_eq!(failure.instance, ID);
+        assert_eq!(failure.file, "Taken", "失败那句话要指名是哪一行");
+        assert_eq!(failure.op, Some(SavesFailureOp::Backup));
+    }
+}
+
+/// **在飞闸门**：三条写命令一条都不落 core —— 盘上指纹前后一致、世界还在、备份落点没被建，
+/// 而且回的是 `GameRunning`（不是"写盘失败"）。
+///
+/// 抓得住：把闸门放回 UI（只灰按钮）——那时 `dispatch(..., running = true)` 会真的删掉世界，
+/// 这条用例立刻红（指纹变了 / 世界不在 / `kind` 不是 `GameRunning`）。
+#[test]
+fn write_commands_do_not_touch_the_disk_while_the_game_is_running() {
+    let (_root, env, run) = fixture("saves-running");
+    world(&run, "Doomed");
+    let before = fingerprint(&run);
+    let (tx, rx) = super::super::super::job::channel();
+
+    let commands = [
+        SavesCommand::RenameWorld {
+            id: ID.to_string(),
+            dir: "Doomed".to_string(),
+            to: "Renamed".to_string(),
+        },
+        SavesCommand::DeleteWorld {
+            id: ID.to_string(),
+            dir: "Doomed".to_string(),
+        },
+        SavesCommand::BackupWorld {
+            id: ID.to_string(),
+            dir: "Doomed".to_string(),
+            dest: None,
+        },
+    ];
+    for command in commands {
+        let expected = match &command {
+            SavesCommand::RenameWorld { .. } => SavesFailureOp::Rename,
+            SavesCommand::DeleteWorld { .. } => SavesFailureOp::Delete,
+            _ => SavesFailureOp::Backup,
+        };
+        dispatch(env.clone(), tx.clone(), command, true);
+        let task = rx
+            .recv_timeout(std::time::Duration::from_secs(5))
+            .expect("在飞时 host 没有回结果");
+        let crate::host::HostTask::Saves(report) = task else {
+            panic!("回程不是存档事件");
+        };
+        assert_eq!(report.instance, ID);
+        let failure = report.list.expect_err("在飞时居然写成功了");
+        assert_eq!(
+            failure.kind,
+            SavesFailureKind::GameRunning,
+            "{}",
+            failure.detail
+        );
+        assert_eq!(failure.file, "Doomed", "失败那句话要指名哪一行");
+        assert_eq!(failure.op, Some(expected));
+    }
+
+    assert_eq!(fingerprint(&run), before, "在飞时写了盘");
+    assert!(
+        run.join("saves/Doomed/level.dat").exists(),
+        "世界被删/被改名了"
+    );
+    assert!(
+        !env.layout.data().join("exports").exists(),
+        "在飞时备份落了盘"
+    );
+}
+
+/// 反向：不在飞时同一条 `dispatch` 该真的干（闸门不是把写操作一并关死）。
+#[test]
+fn write_commands_run_when_the_game_is_not_running() {
+    let (_root, env, run) = fixture("saves-idle-dispatch");
+    world(&run, "Doomed");
+    let (tx, rx) = super::super::super::job::channel();
+
+    dispatch(
+        env.clone(),
+        tx.clone(),
+        SavesCommand::DeleteWorld {
+            id: ID.to_string(),
+            dir: "Doomed".to_string(),
+        },
+        false,
+    );
+    let task = rx
+        .recv_timeout(std::time::Duration::from_secs(5))
+        .expect("host 没有回结果");
+    let crate::host::HostTask::Saves(report) = task else {
+        panic!("回程不是存档事件");
+    };
+    let listed = report.list.expect("不在飞时该照常删");
+    assert!(!run.join("saves/Doomed").exists(), "闸门把写操作一并关死了");
+    assert!(matches!(listed.last_op, Some(SavesOped::Deleted { .. })));
+}
+
+/// 读路径**不受**在飞闸门影响（它不改盘）。
+#[test]
+fn read_commands_are_not_blocked_while_the_game_is_running() {
+    let (_root, env, run) = fixture("saves-running-read");
+    world(&run, "Kept");
+    let (tx, rx) = super::super::super::job::channel();
+
+    dispatch(
+        env.clone(),
+        tx.clone(),
+        SavesCommand::List(ID.to_string()),
+        true,
+    );
+    let task = rx
+        .recv_timeout(std::time::Duration::from_secs(5))
+        .expect("host 没有回结果");
+    let crate::host::HostTask::Saves(report) = task else {
+        panic!("回程不是存档事件");
+    };
+    let listed = report.list.expect("在飞时读列表不该被拒");
+    assert_eq!(listed.world_count(), 1);
+    assert!(listed.last_op.is_none());
+}
+
+/// 每一层都认得同一个实例 id（闸门用它算「在不在跑」——漏一条分支就等于那条命令没有闸门）。
+#[test]
+fn every_command_names_its_instance() {
+    let commands = [
+        SavesCommand::List(ID.to_string()),
+        SavesCommand::OpenFolder { id: ID.to_string() },
+        SavesCommand::RenameWorld {
+            id: ID.to_string(),
+            dir: "A".to_string(),
+            to: "B".to_string(),
+        },
+        SavesCommand::DeleteWorld {
+            id: ID.to_string(),
+            dir: "A".to_string(),
+        },
+        SavesCommand::BackupWorld {
+            id: ID.to_string(),
+            dir: "A".to_string(),
+            dest: None,
+        },
+    ];
+    assert_eq!(commands.len(), 5, "新增了命令就要在这里补一条");
+    for command in &commands {
+        assert_eq!(instance_of(command), ID, "{command:?}");
+    }
+}
+
+/// 找不到实例的写操作 ⇒ 同一个具名失败（不是"写成功了个空的"）。
+#[test]
+fn write_ops_on_a_vanished_instance_are_named() {
+    let (_root, env, _run) = fixture("saves-write-unknown");
+    for failure in [
+        rename(&env, "gone", "A", "B").expect_err("改名成功了"),
+        delete(&env, "gone", "A").expect_err("删除成功了"),
+        backup(&env, "gone", "A", None).expect_err("备份成功了"),
+    ] {
+        assert_eq!(failure.kind, SavesFailureKind::InstanceUnavailable);
+        assert_eq!(failure.instance, "gone");
+    }
+    // 这个用例只借 `SavesFailureView` 的类型做一次构造检查：字段齐了才算「结构化失败」。
+    let _probe = SavesFailureView {
+        instance: "gone".to_string(),
+        file: String::new(),
+        op: None,
+        kind: SavesFailureKind::InstanceUnavailable,
+        detail: String::new(),
+    };
+}
diff --git a/crates/presenter/src/host/saves/write.rs b/crates/presenter/src/host/saves/write.rs
new file mode 100644
index 0000000..fac574d
--- /dev/null
+++ b/crates/presenter/src/host/saves/write.rs
@@ -0,0 +1,167 @@
+//! 三个**写操作**的宿主实现（M247）：重命名 / 删除 / 备份导出。
+//!
+//! 从 `host/saves.rs` 拆出（那个文件加完在飞闸门与写失败映射之后越过 400 行硬线）。
+//! 判据与读路径共用的部分留在父模块（[`super::target`] / [`super::run_dir`] / [`super::snapshot`] /
+//! [`super::failure`]）——**派生运行目录只有一条路**，写路径不另算一份。
+//!
+//! | 函数 | 干什么 |
+//! |---|---|
+//! | [`spawn_rename`] / [`spawn_delete`] / [`spawn_backup`] | 起后台线程跑完再把**新快照 + 回执**送回去 |
+//! | `rename` / `delete` / `backup` | 前台实现（测试直接调它们，不必绕线程） |
+//! | [`export_dir`] | 备份的默认落点 `<data>/exports/saves/` |
+//! | [`write_failure`] | core 的八类写失败 → DTO 的八类（一一对应，不折叠） |
+//!
+//! 三个 `spawn_*` 都**先跑 core 的写**再 `snapshot`：界面画的永远是磁盘上的真相，
+//! 回执只说这件事动的是哪一条（见父模块的「三个写操作的回程形状」）。
+
+use std::path::PathBuf;
+
+use unlucky_core::game::saves::{self, SavesWriteError, SavesWriteKind};
+
+use crate::dto::{
+    InstanceId, SavesFailureKind, SavesFailureOp, SavesFailureView, SavesListView, SavesOped,
+};
+
+use super::super::env::HostEnv;
+use super::super::job::{spawn, JobSender};
+use super::{failure, snapshot, target, Report};
+
+/// 后台重命名一个世界，**并把刷新后的快照与回执一起带回来**。
+pub fn spawn_rename(env: HostEnv, tx: JobSender, id: InstanceId, dir: String, to: String) {
+    spawn("saves-rename", move || {
+        let report = Report {
+            instance: id.clone(),
+            list: rename(&env, &id, &dir, &to),
+        };
+        let _ = tx.send(crate::host::HostTask::Saves(Box::new(report)));
+    });
+}
+
+/// 后台删除一个世界（**UI 已经二次确认过**；host 侧照样重新过边界校验）。
+pub fn spawn_delete(env: HostEnv, tx: JobSender, id: InstanceId, dir: String) {
+    spawn("saves-delete", move || {
+        let report = Report {
+            instance: id.clone(),
+            list: delete(&env, &id, &dir),
+        };
+        let _ = tx.send(crate::host::HostTask::Saves(Box::new(report)));
+    });
+}
+
+/// 后台把一个世界备份成 zip（落点见 [`export_dir`]），并带回新快照。
+pub fn spawn_backup(
+    env: HostEnv,
+    tx: JobSender,
+    id: InstanceId,
+    dir: String,
+    dest: Option<String>,
+) {
+    spawn("saves-backup", move || {
+        let report = Report {
+            instance: id.clone(),
+            list: backup(&env, &id, &dir, dest.as_deref()),
+        };
+        let _ = tx.send(crate::host::HostTask::Saves(Box::new(report)));
+    });
+}
+
+/// 重命名 → 再列一遍（回执里记「谁改成了什么」）。
+pub(super) fn rename(
+    env: &HostEnv,
+    id: &str,
+    from: &str,
+    to: &str,
+) -> Result<SavesListView, SavesFailureView> {
+    let (instance, run_dir) = target(env, id)?;
+    saves::rename_world(&run_dir, from, to)
+        .map_err(|error| write_failure(&instance.id, SavesFailureOp::Rename, from, &error))?;
+    snapshot(
+        &instance,
+        &run_dir,
+        Some(SavesOped::Renamed {
+            from: from.to_string(),
+            to: to.to_string(),
+        }),
+    )
+}
+
+/// 删除 → 再列一遍（回执里记被删掉的那个名字）。
+pub(super) fn delete(
+    env: &HostEnv,
+    id: &str,
+    dir: &str,
+) -> Result<SavesListView, SavesFailureView> {
+    let (instance, run_dir) = target(env, id)?;
+    saves::delete_world(&run_dir, dir)
+        .map_err(|error| write_failure(&instance.id, SavesFailureOp::Delete, dir, &error))?;
+    snapshot(
+        &instance,
+        &run_dir,
+        Some(SavesOped::Deleted {
+            dir: dir.to_string(),
+        }),
+    )
+}
+
+/// 备份 → 再列一遍（回执里记落点路径 / 字节数 / 被跳过的链接数）。
+pub(super) fn backup(
+    env: &HostEnv,
+    id: &str,
+    dir: &str,
+    dest: Option<&str>,
+) -> Result<SavesListView, SavesFailureView> {
+    let (instance, run_dir) = target(env, id)?;
+    let dest = dest.map_or_else(|| export_dir(env), PathBuf::from);
+    let done = saves::backup_world(&run_dir, dir, &dest)
+        .map_err(|error| write_failure(&instance.id, SavesFailureOp::Backup, dir, &error))?;
+    let file = done
+        .path
+        .file_name()
+        .map(|name| name.to_string_lossy().into_owned())
+        .unwrap_or_default();
+    snapshot(
+        &instance,
+        &run_dir,
+        Some(SavesOped::BackedUp {
+            dir: dir.to_string(),
+            file,
+            path: done.path.display().to_string(),
+            bytes: done.bytes,
+            skipped: done.skipped,
+        }),
+    )
+}
+
+/// 备份的默认落点：`<data>/exports/saves/`（见模块文档「备份落点」一节）。
+fn export_dir(env: &HostEnv) -> PathBuf {
+    env.layout.data().join("exports").join("saves")
+}
+
+/// core 的写失败 → 具名类别 + 「路径：原文」（**不翻译**，翻译在 app 层）。
+///
+/// 八个类别一一对应，没有一个落到「未知」兜底里：兜底会变成静默（用户只看到"失败了"）。
+pub(super) fn write_failure(
+    instance: &str,
+    op: SavesFailureOp,
+    file: &str,
+    error: &SavesWriteError,
+) -> SavesFailureView {
+    let kind = match error.kind {
+        SavesWriteKind::UnsafeName => SavesFailureKind::WriteUnsafeName,
+        SavesWriteKind::SymbolicLink => SavesFailureKind::WriteSymlink,
+        SavesWriteKind::NotFound => SavesFailureKind::WriteMissing,
+        SavesWriteKind::NotADirectory => SavesFailureKind::WriteNotADirectory,
+        SavesWriteKind::Conflict => SavesFailureKind::WriteConflict,
+        SavesWriteKind::Boundary => SavesFailureKind::WriteBoundary,
+        SavesWriteKind::TooLarge => SavesFailureKind::WriteTooLarge,
+        SavesWriteKind::Io => SavesFailureKind::WriteFailed,
+    };
+    let mut failure = failure(
+        instance,
+        kind,
+        format!("{}：{}", error.path.display(), error.detail),
+    );
+    failure.file = file.to_string();
+    failure.op = Some(op);
+    failure
+}
diff --git a/crates/presenter/src/state/saves.rs b/crates/presenter/src/state/saves.rs
index cd99dea..714decb 100644
--- a/crates/presenter/src/state/saves.rs
+++ b/crates/presenter/src/state/saves.rs
@@ -11,6 +11,23 @@
 //! | [`SavesState::pending`] | 哪个世界的哪个写操作在飞 | 与 [`super::mods::ModsState::pending`] **同一条先例**：只用来把那一行的按钮置灰，**不做乐观回显**（列表只跟快照走） |
 //! | [`SavesState::confirm`] | 删除确认框**正在等谁** | 模态队列只画框、不记得"确认之后要删哪个世界"；而点主按钮的那一刻是 `app/update/dialog.rs`，那里只能从状态里取 |
 //!
+//! ## 生命周期（谁写、谁清、何时必须清）
+//!
+//! | 字段 | 谁写 | 谁清 | 必须清的时刻 |
+//! |---|---|---|---|
+//! | `draft` | `start_rename`（预填当前磁盘名）、`edit_rename`（每敲一个字） | `cancel_rename` / `take_rename`（提交时取走）/ `mark_pending`（请求已发出，草稿没用了）/ `bind` / `changed` | **换实例**、**请求发出**、**快照回来**：三者之后草稿都属于"上一次对话"，留着会让「改名」按钮改到一个已经在别的实例上的名字 |
+//! | `pending` | `mark_pending`（发请求之前，一跳都不等） | `changed`（成功）/ `failed`（失败也要清——**按钮不能永远灰着**，用户要能直接再点一次）/ `bind` | **任何一次后台往返收尾**、**换实例** |
+//! | `confirm` | `ask_delete`（点「删除」时，随后 app 层把模态框压进队列） | [`SavesState::take_confirm`]（**取走即清**）/ `clear_confirm`（取消或关框）/ `failed` / `bind` | **点主按钮那一刻**、**取消/关闭模态框**、**换实例** |
+//!
+//! ### `confirm` 的「取走即清」是一条**安全不变量**
+//!
+//! 主按钮走的是 `take_confirm()`：拿到目标的同时字段被置空。所以同一次确认**连点两下只会发一条
+//! 删除**——第二下拿不到目标，只关框。这不是洁癖：删除不可逆，一次误触发两条命令意味着第二条
+//! 会去删一个已经被删掉的名字（或者更糟：用户在两次点击之间切了实例，而旧目标还留着）。
+//! 取消/关闭也必须清，否则"上一次取消掉的删除"会挂在状态里，等下一次点「确定」时兑现。
+//! 用例：`switching_instances_drops_draft_pending_and_confirm`（换实例三样一起清）、
+//! `the_delete_confirmation_hands_out_once`（取走即清、取消后不再有目标）。
+//!
 //! # 为什么快照住在这里而不是页面
 //!
 //! 「列表画的永远是磁盘上的真相」是本模块唯一要保证的事，所以：