diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/direct_project_history.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/direct_project_history.rs
index 130c01549..133409a7d 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/direct_project_history.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/direct_project_history.rs
@@ -1,3 +1,4 @@
+use super::direct_thread_item_identity;
 use super::runtime_actions::acquire_game_creator_agent_runtime_project_write_lock_with_wait;
 use crate::config::prepare_game_creator_private_path_for_read;
 use crate::project::{
@@ -102,63 +103,114 @@ fn record(item: &Value) -> Result<String, String> {
 
 const DIRECT_PROJECT_HISTORY_REVERSE_SCAN_CHUNK_BYTES: usize = 16 * 1024;
 
+/// 从文件尾向前回读到的一行。
+///
+/// `terminated` 表示这行后面确实有换行符：文件里只有末行可能没有换行，那种行是 append
+/// 侧承诺会修复的截断尾，解析失败时按"历史到此结束"处理，而不是报错。
+struct DirectProjectHistoryReverseLine {
+    bytes: Vec<u8>,
+    terminated: bool,
+}
+
+/// 从文件尾向前逐行产出 `project.jsonl`。
+///
+/// 历史会随项目长到 MB 级，而"最近一屏"和"按 id 回扫"都只关心尾部若干行：两者共用这一套
+/// 按块回读，"读一屏"不必再从文件头逐行读到尾。
+struct DirectProjectHistoryReverseLines {
+    path: PathBuf,
+    file: File,
+    /// 已读进内存、但还没被换行切出来的更早字节。
+    pending: Vec<u8>,
+    chunk: Vec<u8>,
+    /// 下一次回读的起始偏移；0 表示文件头已经读完。
+    position: u64,
+}
+
+impl DirectProjectHistoryReverseLines {
+    fn open(path: &Path) -> Result<Self, String> {
+        let file = File::open(path)
+            .map_err(|error| format!("打开 DirectProject 历史失败：{}: {error}", path.display()))?;
+        let position = file
+            .metadata()
+            .map_err(|error| {
+                format!(
+                    "读取 DirectProject 历史元数据失败：{}: {error}",
+                    path.display()
+                )
+            })?
+            .len();
+        Ok(Self {
+            path: path.to_path_buf(),
+            file,
+            pending: Vec::new(),
+            chunk: vec![0u8; DIRECT_PROJECT_HISTORY_REVERSE_SCAN_CHUNK_BYTES],
+            position,
+        })
+    }
+
+    fn next_line(&mut self) -> Result<Option<DirectProjectHistoryReverseLine>, String> {
+        loop {
+            if let Some(newline) = self.pending.iter().rposition(|byte| *byte == b'\n') {
+                let bytes = self.pending[newline + 1..].to_vec();
+                self.pending.truncate(newline);
+                return Ok(Some(DirectProjectHistoryReverseLine {
+                    bytes,
+                    terminated: true,
+                }));
+            }
+            if self.position == 0 {
+                if self.pending.is_empty() {
+                    return Ok(None);
+                }
+                return Ok(Some(DirectProjectHistoryReverseLine {
+                    bytes: std::mem::take(&mut self.pending),
+                    terminated: false,
+                }));
+            }
+            let read_len = usize::try_from(self.position)
+                .unwrap_or(usize::MAX)
+                .min(self.chunk.len());
+            self.position -= read_len as u64;
+            self.file
+                .seek(SeekFrom::Start(self.position))
+                .map_err(|error| {
+                    format!(
+                        "定位 DirectProject 历史失败：{}: {error}",
+                        self.path.display()
+                    )
+                })?;
+            self.file
+                .read_exact(&mut self.chunk[..read_len])
+                .map_err(|error| {
+                    format!(
+                        "读取 DirectProject 历史失败：{}: {error}",
+                        self.path.display()
+                    )
+                })?;
+            let mut combined = self.chunk[..read_len].to_vec();
+            combined.extend_from_slice(&self.pending);
+            self.pending = combined;
+        }
+    }
+}
+
 fn find_direct_project_history_item_by_id_at(
     path: &Path,
     item_id: &str,
 ) -> Result<Option<Value>, String> {
     fire_direct_project_history_scan_probe(DIRECT_PROJECT_HISTORY_SCAN_PROBE_STARTED);
-    let mut file = File::open(path)
-        .map_err(|error| format!("打开 DirectProject 历史失败：{}: {error}", path.display()))?;
-    let mut position = file
-        .metadata()
-        .map_err(|error| {
-            format!(
-                "读取 DirectProject 历史元数据失败：{}: {error}",
-                path.display()
-            )
-        })?
-        .len();
-    let mut pending = Vec::new();
-    let mut chunk = vec![0u8; DIRECT_PROJECT_HISTORY_REVERSE_SCAN_CHUNK_BYTES];
-
-    loop {
-        if position == 0 {
-            break;
-        }
-        let read_len = usize::try_from(position)
-            .unwrap_or(usize::MAX)
-            .min(chunk.len());
-        position -= read_len as u64;
-        file.seek(SeekFrom::Start(position))
-            .map_err(|error| format!("定位 DirectProject 历史失败：{}: {error}", path.display()))?;
-        file.read_exact(&mut chunk[..read_len])
-            .map_err(|error| format!("读取 DirectProject 历史失败：{}: {error}", path.display()))?;
-
-        let mut combined = Vec::with_capacity(read_len + pending.len());
-        combined.extend_from_slice(&chunk[..read_len]);
-        combined.extend_from_slice(&pending);
-        let mut line_end = combined.len();
-        while let Some(newline) = combined[..line_end].iter().rposition(|byte| *byte == b'\n') {
-            let line = &combined[newline + 1..line_end];
-            if !line.is_empty() {
-                if let Some(item) = direct_project_history_item_from_line(path, line)? {
-                    if item.get("id").and_then(Value::as_str) == Some(item_id) {
-                        return Ok(Some(item));
-                    }
+    let mut lines = DirectProjectHistoryReverseLines::open(path)?;
+    while let Some(line) = lines.next_line()? {
+        match direct_project_history_item_from_line(path, &line.bytes) {
+            Ok(Some(item)) => {
+                if item.get("id").and_then(Value::as_str) == Some(item_id) {
+                    return Ok(Some(item));
                 }
             }
-            line_end = newline;
-        }
-        pending = combined[..line_end].to_vec();
-    }
-
-    if !pending.is_empty() {
-        // The append path repairs an unterminated final JSONL record before
-        // writing. A duplicate scan must not reject that repairable tail.
-        if let Ok(Some(item)) = direct_project_history_item_from_line(path, &pending) {
-            if item.get("id").and_then(Value::as_str) == Some(item_id) {
-                return Ok(Some(item));
-            }
+            Ok(None) => {}
+            // 末行没有换行符：append 侧会修复这条截断尾，幂等回扫不能因此失败。
+            Err(_) if !line.terminated => break,
+            Err(error) => return Err(error),
         }
     }
     Ok(None)
@@ -530,46 +582,93 @@ fn read_direct_project_history_entries_at(root: &Path) -> Result<Vec<(Value, u64
     Ok(items)
 }
 
+/// 从文件尾向前回扫一屏历史，返回 `(条目, 还有更早的条目, 记录时间, 本屏最老一条的 itemId)`。
+///
+/// 分页锚点就是条目身份（`itemId`），收满 `limit` 条可显示条目后再多看一眼"还有没有更早的
+/// 条目"就停，不回读整份历史。
 pub(crate) fn read_direct_project_history_items_slice_at(
     root: &Path,
     before_item_id: Option<&str>,
     limit: usize,
-) -> Result<(Vec<Value>, bool, BTreeMap<String, u64>), String> {
-    let items = read_direct_project_history_entries_at(root)?;
-    let end = match before_item_id {
-        Some(item_id) => items
-            .iter()
-            .position(|(item, _)| item.get("id").and_then(Value::as_str) == Some(item_id))
-            .ok_or_else(|| format!("DirectProject 历史中不存在 item：{item_id}"))?,
-        None => items.len(),
-    };
+) -> Result<(Vec<Value>, bool, BTreeMap<String, u64>, Option<String>), String> {
+    let path = history_path(root);
+    if !prepare_game_creator_private_path_for_read(&path, false, "DirectProject 历史")? {
+        return Ok((Vec::new(), false, BTreeMap::new(), None));
+    }
     let bounded_limit = limit.clamp(1, 200);
-    let start = end.saturating_sub(bounded_limit);
-    let slice = &items[start..end];
-    let timestamps = slice
+    let mut lines = DirectProjectHistoryReverseLines::open(&path)?;
+    let mut newest_first: Vec<(Value, u64)> = Vec::new();
+    // 锚点所在行本身不进窗口：它是"下一屏"的边界。
+    let mut anchor_seen = before_item_id.is_none();
+    let mut has_more = false;
+    while let Some(line) = lines.next_line()? {
+        if line.bytes.iter().all(u8::is_ascii_whitespace) {
+            continue;
+        }
+        let parsed: Value = match serde_json::from_slice(&line.bytes) {
+            Ok(value) => value,
+            // 与顺序读取一致：只有末行没有换行符时，解析失败才按"可修复的截断尾"结束。
+            Err(_) if !line.terminated => break,
+            Err(error) => {
+                return Err(format!(
+                    "解析 DirectProject 历史失败：{}: {error}",
+                    path.display()
+                ))
+            }
+        };
+        let Some(item) = direct_project_history_item_from_parsed_line(&path, &parsed)? else {
+            continue;
+        };
+        if !anchor_seen {
+            anchor_seen = before_item_id.is_some_and(|anchor| {
+                direct_thread_item_identity(&item).as_deref() == Some(anchor)
+            });
+            continue;
+        }
+        if is_direct_project_internal_context_item(&item) {
+            continue;
+        }
+        if newest_first.len() == bounded_limit {
+            // 收满一屏之后再见一条可显示条目，就足以说明还有更早的历史。
+            has_more = true;
+            break;
+        }
+        let recorded_at = parsed
+            .get("recordedAt")
+            .and_then(Value::as_u64)
+            .unwrap_or(0);
+        newest_first.push((item, recorded_at));
+    }
+    if !anchor_seen {
+        return Err(format!(
+            "DirectProject 历史中不存在 item：{}",
+            before_item_id.unwrap_or_default()
+        ));
+    }
+    newest_first.reverse();
+    let recorded_at_ms = newest_first
         .iter()
         .filter_map(|(item, at)| {
-            let id = item.get("id").and_then(Value::as_str)?;
-            (*at > 0).then(|| (id.to_string(), *at))
+            let identity = direct_thread_item_identity(item)?;
+            (*at > 0).then_some((identity, *at))
         })
         .collect();
+    let first_item_id = newest_first
+        .first()
+        .and_then(|(item, _)| direct_thread_item_identity(item));
     Ok((
-        slice.iter().map(|(item, _)| item.clone()).collect(),
-        start > 0,
-        timestamps,
+        newest_first.into_iter().map(|(item, _)| item).collect(),
+        has_more,
+        recorded_at_ms,
+        first_item_id,
     ))
 }
 
+/// 最新一条可显示条目的 itemId：首屏历史锚点。
+///
+/// 与"最近一屏"共用尾部回扫，读一行就能返回，不回读整份历史。
 pub(crate) fn read_direct_project_last_item_id_at(root: &Path) -> Result<Option<String>, String> {
-    Ok(read_direct_project_history_items_at(root)?
-        .into_iter()
-        .rev()
-        .find_map(|item| {
-            item.get("id")
-                .and_then(Value::as_str)
-                .filter(|id| !id.is_empty())
-                .map(str::to_string)
-        }))
+    Ok(read_direct_project_history_items_slice_at(root, None, 1)?.3)
 }
 
 pub(crate) fn read_direct_project_chat_history_at(
@@ -648,12 +747,12 @@ mod tests {
             "content": [{"type": "input_text", "text": "修改游戏"}],
         });
         append_direct_project_user_message_at(root.path(), &item).unwrap();
-        let (items, _, timestamps) =
+        let (items, _, timestamps, _) =
             super::read_direct_project_history_items_slice_at(root.path(), None, 20).unwrap();
         assert_eq!(items, vec![item.clone()]);
         assert!(timestamps["sent-message"] > 0);
         append_direct_project_user_message_at(root.path(), &item).unwrap();
-        let (_, _, reloaded) =
+        let (_, _, reloaded, _) =
             super::read_direct_project_history_items_slice_at(root.path(), None, 20).unwrap();
         assert_eq!(timestamps, reloaded);
     }
@@ -662,7 +761,7 @@ mod tests {
     fn old_history_without_envelope_time_stays_unknown() {
         let root = init_history_project("history-unknown-time");
         write_history_lines(root.path(), &[RESPONSE_ITEM_ROW]);
-        let (_, _, timestamps) =
+        let (_, _, timestamps, _) =
             super::read_direct_project_history_items_slice_at(root.path(), None, 20).unwrap();
         assert!(timestamps.is_empty());
         assert_eq!(
@@ -674,6 +773,71 @@ mod tests {
         );
     }
 
+    /// 判据：读一屏只回扫文件尾，不碰文件头。
+    ///
+    /// 文件头放一条坏行（JSON 不合法），只要读取只覆盖"尾部一屏 + 一条"的范围就必须成功；
+    /// 一旦实现退回"从文件头逐行读到尾"，这条用例会因为坏行直接失败。
+    #[test]
+    fn history_window_reads_from_the_tail_without_parsing_the_head() {
+        let root = init_history_project("history-tail-scan");
+        let head = r#"{"type":"response_item","payload":{"type":"message","role":"user","id":"head-broken","content":[{"type":"input_text","text":"坏行"}"#;
+        write_history_lines(
+            root.path(),
+            &[
+                head,
+                &RESPONSE_ITEM_ROW.replace("codex-item-2", "codex-item-1"),
+                RESPONSE_ITEM_ROW,
+            ],
+        );
+        let (items, has_more, _, first_item_id) =
+            super::read_direct_project_history_items_slice_at(root.path(), None, 1).unwrap();
+        let ids = items
+            .iter()
+            .filter_map(|item| item.get("id").and_then(Value::as_str))
+            .collect::<Vec<_>>();
+        assert_eq!(ids, vec!["codex-item-2"]);
+        assert!(has_more);
+        assert_eq!(first_item_id.as_deref(), Some("codex-item-2"));
+    }
+
+    /// 判据：分页锚点是"本窗口最老一条的归一身份"，逐屏向前不重不漏。
+    #[test]
+    fn history_window_paginates_upwards_by_identity_anchor() {
+        let root = init_history_project("history-pagination");
+        write_history_lines(
+            root.path(),
+            &[
+                &RESPONSE_ITEM_ROW.replace("codex-item-2", "codex-item-1"),
+                &RESPONSE_ITEM_ROW.replace("codex-item-2", "codex-item-2"),
+                &RESPONSE_ITEM_ROW.replace("codex-item-2", "codex-item-3"),
+            ],
+        );
+        let (newest, has_more, _, first_item_id) =
+            super::read_direct_project_history_items_slice_at(root.path(), None, 2).unwrap();
+        let ids = newest
+            .iter()
+            .filter_map(|item| item.get("id").and_then(Value::as_str))
+            .collect::<Vec<_>>();
+        assert_eq!(ids, vec!["codex-item-2", "codex-item-3"]);
+        assert!(has_more);
+        assert_eq!(first_item_id.as_deref(), Some("codex-item-2"));
+
+        let (older, has_more, _, first_item_id) =
+            super::read_direct_project_history_items_slice_at(
+                root.path(),
+                first_item_id.as_deref(),
+                2,
+            )
+            .unwrap();
+        let ids = older
+            .iter()
+            .filter_map(|item| item.get("id").and_then(Value::as_str))
+            .collect::<Vec<_>>();
+        assert_eq!(ids, vec!["codex-item-1"]);
+        assert!(!has_more);
+        assert_eq!(first_item_id.as_deref(), Some("codex-item-1"));
+    }
+
     /// 判据：争用类失败会被"有界退避重试"真的吃掉，最终把条目落一行。
     ///
     /// 注入标记是"让接下来 N 次单次尝试返回争用失败"；退避表只补一次重试，所以注入 1 次
diff --git a/apps/ai-game-creator-shell/src-tauri/src/commands.rs b/apps/ai-game-creator-shell/src-tauri/src/commands.rs
index 696aff810..eff140194 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/commands.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/commands.rs
@@ -5306,31 +5306,6 @@ pub(crate) async fn read_agent_runtime_error_detail(
     .await
     .map_err(|error| format!("读取统一错误诊断后台任务失败：{error}"))?
 }
-#[tauri::command]
-pub(crate) async fn read_direct_tool_calls(
-    project_path: String,
-) -> Result<Vec<DirectToolCall>, String> {
-    tauri::async_runtime::spawn_blocking(move || {
-        let root = Path::new(project_path.trim());
-        enforce_project_permission_policy(root, "conversation.read")?;
-        read_direct_tool_calls_at(root)
-    })
-    .await
-    .map_err(|error| format!("读取工具调用历史后台任务失败：{error}"))?
-}
-
-#[tauri::command]
-pub(crate) async fn read_direct_turn_stream(
-    project_path: String,
-) -> Result<Vec<DirectTurnStreamItem>, String> {
-    tauri::async_runtime::spawn_blocking(move || {
-        let root = Path::new(project_path.trim());
-        enforce_project_permission_policy(root, "conversation.read")?;
-        read_direct_turn_stream_at(root)
-    })
-    .await
-    .map_err(|error| format!("读取回合流历史后台任务失败：{error}"))?
-}
 
 #[tauri::command]
 pub(crate) fn list_game_creator_direct_active_turns(
@@ -5378,20 +5353,15 @@ pub(crate) async fn read_direct_project_history_slice(
     tauri::async_runtime::spawn_blocking(move || {
         let root = Path::new(project_path.trim());
         enforce_project_permission_policy(root, "conversation.read")?;
-        let (items, has_more, item_timestamps) = read_direct_project_history_items_slice_at(
-            root,
-            before_item_id.as_deref(),
-            limit.unwrap_or(20),
-        )?;
-        let first_item_id = items
-            .first()
-            .and_then(|item| item.get("id"))
-            .and_then(serde_json::Value::as_str)
-            .map(str::to_string);
-        let items = direct_thread_items_from_history(root, &items, |item| {
-            item.get("id")
-                .and_then(serde_json::Value::as_str)
-                .and_then(|id| item_timestamps.get(id).copied())
+        let (raw_items, has_more, recorded_at_ms, first_item_id) =
+            read_direct_project_history_items_slice_at(
+                root,
+                before_item_id.as_deref(),
+                limit.unwrap_or(20),
+            )?;
+        let items = direct_thread_items_from_history(root, &raw_items, |item| {
+            direct_thread_item_identity(item)
+                .and_then(|identity| recorded_at_ms.get(&identity).copied())
                 .unwrap_or_default()
         });
         Ok(DirectThreadHistorySlice {
diff --git a/apps/ai-game-creator-shell/src-tauri/src/main.rs b/apps/ai-game-creator-shell/src-tauri/src/main.rs
index bec55a981..c240a21fc 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/main.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/main.rs
@@ -2782,8 +2782,6 @@ fn main() {
             archive_game_creator_agent_session,
             read_local_conversation,
             read_direct_project_conversation,
-            read_direct_tool_calls,
-            read_direct_turn_stream,
             read_agent_runtime_error_detail,
             list_game_creator_direct_active_turns,
             subscribe_direct_project_thread,