diff --git a/core/src/repositories/cas_repository.rs b/core/src/repositories/cas_repository.rs
index 1b696c5..3470871 100644
--- a/core/src/repositories/cas_repository.rs
+++ b/core/src/repositories/cas_repository.rs
@@ -153,11 +153,14 @@ pub trait CasRepository: Send + Sync {
     /// # 示例
     ///
     /// ```rust,ignore
-    /// if repository.exists(&object_id).await {
+    /// if repository.exists(&object_id).await? {
     ///     println!("Object exists");
     /// }
     /// ```
-    async fn exists(&self, id: &ObjectId) -> bool;
+    ///
+    /// 返回 `Result` 以便调用方区分“对象不存在”（`Ok(false)`）与底层存储/IO 故障
+    /// （`Err`），而不是把故障静默当成不存在。
+    async fn exists(&self, id: &ObjectId) -> crate::Result<bool>;
 
     /// 增加引用计数
     ///
diff --git a/crates/bat-cas-engine/src/repository.rs b/crates/bat-cas-engine/src/repository.rs
index 1c0f9fc..ea7c199 100644
--- a/crates/bat-cas-engine/src/repository.rs
+++ b/crates/bat-cas-engine/src/repository.rs
@@ -37,7 +37,7 @@ impl FileSystemCasRepository {
     /// 存储对象并增加引用计数。
     pub async fn store(&self, data: &[u8]) -> Result<Hash> {
         let hash = compute_hash(data);
-        let existed = self.storage.exists(&hash).await;
+        let existed = self.storage.exists(&hash).await?;
         let stored_hash = self.storage.put(data).await?;
 
         // 单条 UPSERT 原子建行并 +1：对象行不会在 store 期间以 ref_count=0
@@ -75,13 +75,13 @@ impl FileSystemCasRepository {
     }
 
     /// 检查对象是否存在。
-    pub async fn exists(&self, hash: &Hash) -> bool {
+    pub async fn exists(&self, hash: &Hash) -> Result<bool> {
         self.storage.exists(hash).await
     }
 
     /// 增加引用计数。
     pub async fn add_reference(&self, hash: &Hash) -> Result<u64> {
-        if !self.storage.exists(hash).await {
+        if !self.storage.exists(hash).await? {
             return Err(CasError::ObjectNotFound(hash.to_string()));
         }
 
@@ -169,8 +169,8 @@ mod tests {
         repo.remove_reference(&delete).await.unwrap();
 
         assert_eq!(repo.gc().await.unwrap(), 1);
-        assert!(repo.exists(&keep).await);
-        assert!(!repo.exists(&delete).await);
+        assert!(repo.exists(&keep).await.unwrap());
+        assert!(!repo.exists(&delete).await.unwrap());
         assert!(matches!(
             repo.get_reference_count(&delete).await,
             Err(CasError::ObjectNotFound(_))
@@ -209,7 +209,7 @@ mod tests {
         assert_eq!(repo.get_reference_count(&hash).await.unwrap(), 1);
         assert!(repo.gc_candidates().await.unwrap().is_empty());
         assert_eq!(repo.gc().await.unwrap(), 0);
-        assert!(repo.exists(&hash).await);
+        assert!(repo.exists(&hash).await.unwrap());
     }
 
     #[tokio::test]
@@ -224,7 +224,7 @@ mod tests {
         assert_eq!(repo.add_reference(&hash).await.unwrap(), 1);
         // gc 的原子闸门应跳过它，对象文件保留。
         assert_eq!(repo.gc().await.unwrap(), 0);
-        assert!(repo.exists(&hash).await);
+        assert!(repo.exists(&hash).await.unwrap());
         assert_eq!(repo.get_reference_count(&hash).await.unwrap(), 1);
     }
 
diff --git a/crates/bat-cas-engine/src/storage.rs b/crates/bat-cas-engine/src/storage.rs
index 80de5d0..1b268a7 100644
--- a/crates/bat-cas-engine/src/storage.rs
+++ b/crates/bat-cas-engine/src/storage.rs
@@ -20,7 +20,10 @@ pub trait Storage: Send + Sync {
     async fn get(&self, hash: &Hash) -> Result<Vec<u8>>;
 
     /// 检查对象文件是否存在。
-    async fn exists(&self, hash: &Hash) -> bool;
+    ///
+    /// 返回 `Result` 以便区分“确实不存在”（`Ok(false)`）与底层 IO 故障（`Err`），
+    /// 避免把权限或其它 IO 错误静默当成不存在。
+    async fn exists(&self, hash: &Hash) -> Result<bool>;
 
     /// 删除对象文件。
     async fn delete(&self, hash: &Hash) -> Result<()>;
@@ -115,7 +118,7 @@ impl FileSystemStorage {
     }
 
     async fn validate_existing_object(&self, hash: &Hash) -> Result<bool> {
-        if !self.exists(hash).await {
+        if !self.exists(hash).await? {
             return Ok(false);
         }
 
@@ -249,10 +252,8 @@ impl Storage for FileSystemStorage {
         Ok(data)
     }
 
-    async fn exists(&self, hash: &Hash) -> bool {
-        tokio::fs::try_exists(self.object_path(hash))
-            .await
-            .unwrap_or(false)
+    async fn exists(&self, hash: &Hash) -> Result<bool> {
+        Ok(tokio::fs::try_exists(self.object_path(hash)).await?)
     }
 
     async fn delete(&self, hash: &Hash) -> Result<()> {
@@ -347,10 +348,10 @@ mod tests {
 
         let hash = storage.put(b"Test data").await.unwrap();
 
-        assert!(storage.exists(&hash).await);
+        assert!(storage.exists(&hash).await.unwrap());
         let deleted = storage.delete(&hash).await;
         deleted.unwrap();
-        assert!(!storage.exists(&hash).await);
+        assert!(!storage.exists(&hash).await.unwrap());
     }
 
     #[tokio::test]
diff --git a/infrastructure/src/cas/filesystem.rs b/infrastructure/src/cas/filesystem.rs
index c994ac0..4f34757 100644
--- a/infrastructure/src/cas/filesystem.rs
+++ b/infrastructure/src/cas/filesystem.rs
@@ -92,14 +92,13 @@ impl CasRepository for FileSystemCasRepository {
         Ok(data)
     }
 
-    async fn exists(&self, id: &ObjectId) -> bool {
-        let Ok(hash) = Self::parse_object_id(id) else {
-            return false;
-        };
-        let Ok(engine) = self.engine().await else {
-            return false;
-        };
-        engine.exists(&hash).await
+    async fn exists(&self, id: &ObjectId) -> bat_core::Result<bool> {
+        let hash = Self::parse_object_id(id)?;
+        self.engine()
+            .await?
+            .exists(&hash)
+            .await
+            .map_err(Self::map_error)
     }
 
     async fn add_reference(&self, id: &ObjectId) -> bat_core::Result<u64> {
@@ -176,7 +175,7 @@ mod tests {
         assert_eq!(repo.remove_reference(&id).await.unwrap(), 0);
         assert_eq!(repo.gc().await.unwrap(), 1);
 
-        assert!(!repo.exists(&id).await);
+        assert!(!repo.exists(&id).await.unwrap());
         let missing = repo.get(&id).await;
         assert!(matches!(missing, Err(bat_core::Error::NotFound(_))));
     }
@@ -191,6 +190,23 @@ mod tests {
         assert!(matches!(error, bat_core::Error::InvalidArgument(_)));
     }
 
+    #[tokio::test]
+    async fn exists_distinguishes_missing_from_invalid_id() {
+        let temp_dir = TempDir::new().unwrap();
+        let repo = FileSystemCasRepository::new(temp_dir.path());
+        repo.init().await.unwrap();
+
+        // 合法但不存在的对象：Ok(false)，而非静默错误。
+        let absent = repo.store(b"absent-seed").await.unwrap();
+        repo.remove_reference(&absent).await.unwrap();
+        repo.gc().await.unwrap();
+        assert!(!repo.exists(&absent).await.unwrap());
+
+        // 非法 ObjectId：返回 Err 而非 Ok(false)，让调用方能区分故障。
+        let error = repo.exists(&"not-a-hash".to_string()).await.unwrap_err();
+        assert!(matches!(error, bat_core::Error::InvalidArgument(_)));
+    }
+
     #[tokio::test]
     async fn store_returns_blake3_hex_object_id() {
         let temp_dir = TempDir::new().unwrap();
diff --git a/infrastructure/src/import.rs b/infrastructure/src/import.rs
index 88c6334..9f5f210 100644
--- a/infrastructure/src/import.rs
+++ b/infrastructure/src/import.rs
@@ -576,7 +576,7 @@ mod tests {
 
         assert_eq!(report.imported.len(), 4);
         assert_eq!(report.skipped, vec!["synthetic/catalog.json".to_string()]);
-        assert!(cas.exists(&report.imported[0].object_id).await);
+        assert!(cas.exists(&report.imported[0].object_id).await.unwrap());
         assert_eq!(report.imported[0].resource_type, ResourceType::AssetBundle);
         assert_eq!(
             report.imported[0].category,
diff --git a/infrastructure/tests/synthetic_phase2_import.rs b/infrastructure/tests/synthetic_phase2_import.rs
index 6d886bd..02e216b 100644
--- a/infrastructure/tests/synthetic_phase2_import.rs
+++ b/infrastructure/tests/synthetic_phase2_import.rs
@@ -92,7 +92,7 @@ async fn imports_synthetic_addressables_catalog_bundle_against_golden() {
         .unwrap();
 
     assert_eq!(report.imported.len(), 1);
-    assert!(cas.exists(&report.imported[0].object_id).await);
+    assert!(cas.exists(&report.imported[0].object_id).await.unwrap());
 
     let indexed = resources.list(ResourceQuery::all()).await.unwrap();
     let actual = json!({