diff --git a/easy-agents-document/easy-agents-document-core/src/main/java/com/easyagents/document/core/async/DocumentAsyncTaskManager.java b/easy-agents-document/easy-agents-document-core/src/main/java/com/easyagents/document/core/async/DocumentAsyncTaskManager.java
index 5536b02..156cb86 100644
--- a/easy-agents-document/easy-agents-document-core/src/main/java/com/easyagents/document/core/async/DocumentAsyncTaskManager.java
+++ b/easy-agents-document/easy-agents-document-core/src/main/java/com/easyagents/document/core/async/DocumentAsyncTaskManager.java
@@ -2,6 +2,7 @@ package com.easyagents.document.core.async;
 
 import com.easyagents.core.util.StringUtil;
 import com.easyagents.document.core.exception.DocumentParseException;
+import com.easyagents.document.core.exception.DocumentAsyncTaskNotFoundException;
 import com.easyagents.document.core.entity.ParseResponse;
 import com.easyagents.document.core.entity.ParseTaskInfo;
 import com.easyagents.document.core.entity.ParseTaskStatus;
@@ -135,7 +136,7 @@ public class DocumentAsyncTaskManager {
         }
         DocumentAsyncTaskRecord record = repository.find(taskId);
         if (record == null) {
-            throw new DocumentParseException("Document async task not found: " + taskId);
+            throw new DocumentAsyncTaskNotFoundException(taskId);
         }
         return record;
     }
diff --git a/easy-agents-document/easy-agents-document-core/src/main/java/com/easyagents/document/core/exception/DocumentAsyncTaskNotFoundException.java b/easy-agents-document/easy-agents-document-core/src/main/java/com/easyagents/document/core/exception/DocumentAsyncTaskNotFoundException.java
new file mode 100644
index 0000000..cbe9d07
--- /dev/null
+++ b/easy-agents-document/easy-agents-document-core/src/main/java/com/easyagents/document/core/exception/DocumentAsyncTaskNotFoundException.java
@@ -0,0 +1,29 @@
+package com.easyagents.document.core.exception;
+
+/**
+ * 进程内异步文档任务不存在。
+ *
+ * <p>本地 Office 解析任务允许使用内存仓库；进程重启后，调用方可以
+ * 通过该异常识别执行实例已经丢失，并从持久化业务任务重新提交。</p>
+ *
+ * @author Codex
+ * @since 2026-09-02
+ */
+public class DocumentAsyncTaskNotFoundException extends DocumentParseException {
+
+    private final String taskId;
+
+    public DocumentAsyncTaskNotFoundException(String taskId) {
+        super("Document async task not found: " + taskId);
+        this.taskId = taskId;
+    }
+
+    /**
+     * 获取已丢失的任务 ID。
+     *
+     * @return 任务 ID
+     */
+    public String getTaskId() {
+        return taskId;
+    }
+}
diff --git a/easy-agents-document/easy-agents-document-core/src/test/java/com/easyagents/document/core/async/DocumentAsyncTaskManagerTest.java b/easy-agents-document/easy-agents-document-core/src/test/java/com/easyagents/document/core/async/DocumentAsyncTaskManagerTest.java
index cc10ede..3a72a28 100644
--- a/easy-agents-document/easy-agents-document-core/src/test/java/com/easyagents/document/core/async/DocumentAsyncTaskManagerTest.java
+++ b/easy-agents-document/easy-agents-document-core/src/test/java/com/easyagents/document/core/async/DocumentAsyncTaskManagerTest.java
@@ -4,6 +4,7 @@ import com.easyagents.document.core.entity.ParseResponse;
 import com.easyagents.document.core.entity.ParseResult;
 import com.easyagents.document.core.entity.ParseTaskInfo;
 import com.easyagents.document.core.entity.ParseTaskStatus;
+import com.easyagents.document.core.exception.DocumentAsyncTaskNotFoundException;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -18,6 +19,21 @@ import java.util.concurrent.Executor;
  */
 public class DocumentAsyncTaskManagerTest {
 
+    @Test
+    public void shouldExposeMissingInMemoryTaskAsRecoverableSignal() {
+        DocumentAsyncTaskManager manager = new DocumentAsyncTaskManager(
+            new InMemoryDocumentAsyncTaskRepository(),
+            Runnable::run
+        );
+
+        try {
+            manager.queryTaskInfo("lost-task");
+            Assert.fail("expected DocumentAsyncTaskNotFoundException");
+        } catch (DocumentAsyncTaskNotFoundException error) {
+            Assert.assertEquals("lost-task", error.getTaskId());
+        }
+    }
+
     @Test
     public void shouldTrackTaskLifecycleAndResult() {
         Executor directExecutor = new Executor() {