diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/direct_patch.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/direct_patch.rs
index 2562f9b5e..fd7de081d 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/direct_patch.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/direct_patch.rs
@@ -191,42 +191,60 @@ fn validate_argv(executable: &Path, patch: &str) -> Result<(), String> {
     Ok(())
 }
 
-fn target_fingerprints(targets: &[PatchTarget]) -> BTreeMap<String, Option<String>> {
-    targets
-        .iter()
-        .map(|target| {
-            let digest = (|| {
-                match std::fs::symlink_metadata(&target.absolute) {
-                    Err(error) if error.kind() == std::io::ErrorKind::NotFound => {
-                        return Some("missing".into())
-                    }
-                    Ok(_) => {}
-                    Err(_) => return None,
-                }
+fn target_fingerprints(
+    targets: &[PatchTarget],
+) -> Result<BTreeMap<String, Option<String>>, String> {
+    let mut fingerprints = BTreeMap::new();
+    for target in targets {
+        let digest = match std::fs::symlink_metadata(&target.absolute) {
+            Err(error) if error.kind() == std::io::ErrorKind::NotFound => Some("missing".into()),
+            Ok(_) => {
                 let (mut file, metadata) =
-                    open_project_snapshot_regular_file(&target.absolute, "补丁指纹").ok()?;
+                    open_project_snapshot_regular_file(&target.absolute, "补丁指纹").map_err(
+                        |error| format!("补丁指纹读取失败：{}：{error}", target.relative),
+                    )?;
                 if metadata.len() > TARGET_HASH_MAX_BYTES {
-                    return None;
+                    return Err(format!(
+                        "补丁指纹读取失败：目标文件 {} 大小 {} bytes，超过 {} bytes 上限",
+                        target.relative,
+                        metadata.len(),
+                        TARGET_HASH_MAX_BYTES
+                    ));
                 }
                 let mut digest = Sha256::new();
                 let mut buffer = [0u8; 16 * 1024];
                 let mut total = 0u64;
                 loop {
-                    let count = file.read(&mut buffer).ok()?;
+                    let count = file.read(&mut buffer).map_err(|error| {
+                        format!(
+                            "补丁指纹读取失败：{}：读取文件正文失败：{error}",
+                            target.relative
+                        )
+                    })?;
                     if count == 0 {
                         break;
                     }
                     total += count as u64;
                     if total > TARGET_HASH_MAX_BYTES {
-                        return None;
+                        return Err(format!(
+                            "补丁指纹读取失败：目标文件 {} 在读取期间超过 {} bytes 上限",
+                            target.relative, TARGET_HASH_MAX_BYTES
+                        ));
                     }
                     digest.update(&buffer[..count]);
                 }
                 Some(format!("file:{:x}", digest.finalize()))
-            })();
-            (target.relative.clone(), digest)
-        })
-        .collect()
+            }
+            Err(error) => {
+                return Err(format!(
+                    "补丁指纹检查失败：{}：读取文件元数据失败：{error}",
+                    target.relative
+                ));
+            }
+        };
+        fingerprints.insert(target.relative.clone(), digest);
+    }
+    Ok(fingerprints)
 }
 
 fn analytics_patch_changes(
@@ -278,7 +296,7 @@ fn run_transaction(
     let targets = collect_targets(root, &parsed.hunks)?;
     let executable = session.codex_executor()?;
     validate_argv(&executable, &parsed.patch)?;
-    let before = target_fingerprints(&targets);
+    let before = target_fingerprints(&targets)?;
     let lease = session.admit(EffectKind::Write, None)?;
     let process = runtime.block_on(crate::command_exec::run_owned_codex_patch_at(
         root,
@@ -317,7 +335,7 @@ fn run_transaction(
             error.to_string(),
         ),
     };
-    let after = target_fingerprints(&targets);
+    let after = target_fingerprints(&targets)?;
     let changed_paths = targets
         .iter()
         .filter(|target| {
@@ -439,6 +457,44 @@ mod tests {
         (temp, root.canonicalize().unwrap())
     }
 
+    #[test]
+    fn target_fingerprints_keep_missing_distinct_and_report_read_failures() {
+        let (_temp, root) = project();
+        let missing = PatchTarget {
+            relative: "game/missing.txt".into(),
+            absolute: root.join("game/missing.txt"),
+        };
+        let fingerprints = target_fingerprints(std::slice::from_ref(&missing)).unwrap();
+        assert_eq!(
+            fingerprints.get("game/missing.txt"),
+            Some(&Some("missing".into()))
+        );
+
+        let directory = root.join("game/fingerprint-directory");
+        std::fs::create_dir_all(&directory).unwrap();
+        let directory_target = PatchTarget {
+            relative: "game/fingerprint-directory".into(),
+            absolute: directory,
+        };
+        let error = target_fingerprints(std::slice::from_ref(&directory_target)).unwrap_err();
+        assert!(error.contains("补丁指纹读取失败"), "{error}");
+        assert!(
+            error.contains("打开补丁指纹失败") || error.contains("必须是普通文件"),
+            "{error}"
+        );
+
+        let oversized = root.join("game/fingerprint-oversized.bin");
+        let file = std::fs::File::create(&oversized).unwrap();
+        file.set_len(TARGET_HASH_MAX_BYTES + 1).unwrap();
+        let oversized_target = PatchTarget {
+            relative: "game/fingerprint-oversized.bin".into(),
+            absolute: oversized,
+        };
+        let error = target_fingerprints(std::slice::from_ref(&oversized_target)).unwrap_err();
+        assert!(error.contains("超过"), "{error}");
+        assert!(error.contains("补丁指纹读取失败"), "{error}");
+    }
+
     #[test]
     fn parser_paths_include_every_move_source_and_destination_before_any_write() {
         let (_temp, root) = project();
diff --git a/docs/project-memory/plans/【里程碑】AGC错误具体文本展示-2026-10-04.md b/docs/project-memory/plans/【里程碑】AGC错误具体文本展示-2026-10-04.md
index fed146221..f373aef22 100644
--- a/docs/project-memory/plans/【里程碑】AGC错误具体文本展示-2026-10-04.md
+++ b/docs/project-memory/plans/【里程碑】AGC错误具体文本展示-2026-10-04.md
@@ -85,3 +85,4 @@ DirectProject 回合失败在确认不是客户端内部不可归类故障时，
 - DirectProject 上下文的外部路径元数据读取失败原先统一成 `file-not-found`；现区分确实不存在与权限/磁盘读取错误，后者保留底层正文。
 - 错误报告对话框读取最新错误事件或诊断日志失败时原先只显示“暂不可用/使用快照”；现把读取 IPC/文件正文附在状态提示中，快照回退行为保持不变。
 - WorkspaceLauncher 的清单版本读取、失效事件重读和事件订阅失败原先只写日志或静默回退；现把安全正文送入启动器状态提示，仍保留已有回退刷新路径。
+- Direct 补丁事务的目标指纹读取原先把元数据、打开、正文读取和文件超限都折叠为 `None`，可能误判文件缺失或继续比较；现只对确实 `NotFound` 保留 `missing`，其余失败返回目标相对路径、阶段和底层正文，避免补丁结果被错误归因。