diff --git a/apps/desktop-shell/scripts/check-config.mjs b/apps/desktop-shell/scripts/check-config.mjs
index 4020bbe1c..7c0427abb 100644
--- a/apps/desktop-shell/scripts/check-config.mjs
+++ b/apps/desktop-shell/scripts/check-config.mjs
@@ -1666,9 +1666,17 @@ for (const expectedShareSnippet of [
   'url.origin() != base_url.origin()',
   'DesktopSharePayload::Invalid',
   '"share target is invalid"',
+  'log_desktop_share_failure',
+  'desktop share failed for {label}: {error}',
+  'share_unavailable_response',
+  '"share unavailable"',
   'set_desktop_host_bridge_share_target',
   'share_text_from_value(target)',
+  'log_desktop_share_failure("target.lock", "share target lock poisoned")',
+  'log_desktop_share_failure("target.store", "share target lock poisoned")',
   'share_target_payload_must_be_valid_before_cache',
+  'share_unavailable_response_is_stable',
+  'share_failures_are_logged_without_exposing_native_detail',
   'open_desktop_host_bridge_share',
   'write_desktop_clipboard_text(app, &share_text)',
   '"copied_to_clipboard"',
@@ -1680,6 +1688,13 @@ for (const expectedShareSnippet of [
   }
 }
 
+if (
+  desktopHostBridgeShareSource.includes('failed(request.id.clone(), "host_error", "share target lock poisoned")') ||
+  desktopHostBridgeShareSource.includes('failed(request.id.clone(), "host_error", error.to_string())')
+) {
+  throw new Error('desktop shell share module must hide native share errors');
+}
+
 if (
   !desktopHostBridgeDispatchSource.includes(
     'set_desktop_host_bridge_share_target(&app, &request)',
diff --git a/apps/desktop-shell/src-tauri/src/host_bridge/share.rs b/apps/desktop-shell/src-tauri/src/host_bridge/share.rs
index af0283016..1f2f2abc7 100644
--- a/apps/desktop-shell/src-tauri/src/host_bridge/share.rs
+++ b/apps/desktop-shell/src-tauri/src/host_bridge/share.rs
@@ -28,6 +28,18 @@ fn payload_string<'a>(value: &'a Value, field: &str) -> Option<&'a str> {
         .filter(|text| !text.is_empty())
 }
 
+fn log_desktop_share_failure(label: &str, error: &str) -> bool {
+    if !error.is_empty() {
+        eprintln!("desktop share failed for {label}: {error}");
+    }
+
+    false
+}
+
+fn share_unavailable_response(request: &HostBridgeRequest) -> HostBridgeResponse {
+    failed(request.id.clone(), "host_error", "share unavailable")
+}
+
 fn share_target_payload(value: &Value) -> &Value {
     value.get("target").unwrap_or(value)
 }
@@ -112,11 +124,8 @@ pub(crate) fn share_text_from_request(
         .target
         .lock()
         .map_err(|_| {
-            failed(
-                request.id.clone(),
-                "host_error",
-                "share target lock poisoned",
-            )
+            log_desktop_share_failure("target.lock", "share target lock poisoned");
+            share_unavailable_response(request)
         })?
         .clone();
 
@@ -170,11 +179,10 @@ pub(crate) fn set_desktop_host_bridge_share_target(
             *current_target = Some(target.clone());
             ok(request.id.clone(), json!(true))
         }
-        Err(_) => failed(
-            request.id.clone(),
-            "host_error",
-            "share target lock poisoned",
-        ),
+        Err(_) => {
+            log_desktop_share_failure("target.store", "share target lock poisoned");
+            share_unavailable_response(request)
+        }
     };
     response
 }
@@ -357,4 +365,26 @@ mod tests {
         assert_eq!(error.code, "invalid_request");
         assert_eq!(error.message, "share target is required");
     }
+
+    #[test]
+    fn share_unavailable_response_is_stable() {
+        let response = share_unavailable_response(&request("share.open"));
+
+        assert!(!response.ok);
+        let error = response.error.expect("share error");
+        assert_eq!(error.code, "host_error");
+        assert_eq!(error.message, "share unavailable");
+    }
+
+    #[test]
+    fn share_failures_are_logged_without_exposing_native_detail() {
+        assert!(!log_desktop_share_failure(
+            "target.lock",
+            "share target lock poisoned"
+        ));
+        assert!(!log_desktop_share_failure(
+            "target.store",
+            "share target lock poisoned"
+        ));
+    }
 }
diff --git a/docs/project-memory/shared-memory/decision-log.md b/docs/project-memory/shared-memory/decision-log.md
index 1c8c398bb..06fe24ce1 100644
--- a/docs/project-memory/shared-memory/decision-log.md
+++ b/docs/project-memory/shared-memory/decision-log.md
@@ -3154,6 +3154,12 @@
 - 决策：`apps/mobile-shell/src/host-bridge/share.ts` 必须在 `Share.share(...)` reject 时记录 `mobile share failed for open.share` 日志。HostBridge 对 H5 仍只返回稳定 `share unavailable`，不透传原生分享面板异常明细。
 - 验证方式：`npm run mobile-shell:test -- --run src/host-bridge/share.test.ts`、`npm run mobile-shell:typecheck`、`npm run check:native-shells`、`npm run check:encoding`、`git diff --check`。
 
+## 2026-06-20 桌面壳分享缓存内部异常不得透传
+
+- 背景：桌面壳 `share.setTarget` 和 `share.open` 会读写 Rust 侧分享目标缓存；如果缓存锁异常直接返回 `share target lock poisoned`，H5 会看到 Rust 内部同步原语细节，且开发侧没有统一日志标签定位读缓存还是写缓存失败。
+- 决策：`apps/desktop-shell/src-tauri/src/host_bridge/share.rs` 必须在分享目标缓存读写失败时分别记录 `desktop share failed for target.lock` 或 `desktop share failed for target.store` 日志。HostBridge 对 H5 仍只返回稳定 `share unavailable`，不透传锁状态、内部缓存状态或 Rust 同步原语细节。
+- 验证方式：`cargo test --manifest-path apps/desktop-shell/src-tauri/Cargo.toml host_bridge::share`、`npm run desktop-shell:typecheck`、`npm run check:native-shells`、`npm run check:encoding`、`git diff --check`。
+
 ## 2026-06-20 移动壳门禁脚本必须自登记自扫描
 
 - 背景：Expo 移动壳单端检查已把 `apps/mobile-shell/scripts/` 纳入生产源码扫描入口，但 `check-config.mjs` 自身仍被排除在脚本清单和替身词扫描之外；这会让移动壳与桌面壳门禁结构不一致，也可能让后续门禁反查内容绕过生产替身词规则。
diff --git a/docs/【前端架构】ExpoReactNative与Tauri宿主壳方案-2026-06-17.md b/docs/【前端架构】ExpoReactNative与Tauri宿主壳方案-2026-06-17.md
index 31549ba51..ed6217cdf 100644
--- a/docs/【前端架构】ExpoReactNative与Tauri宿主壳方案-2026-06-17.md
+++ b/docs/【前端架构】ExpoReactNative与Tauri宿主壳方案-2026-06-17.md
@@ -358,6 +358,8 @@ GameBridge 禁止：
 
 2026-06-20 追加：桌面壳网络状态查询系统异常必须可观测。Tauri 桌面壳后台解析网络状态任务失败时必须记录 `desktop network failed for status.resolve` 日志；HostBridge 回包仍只暴露稳定 `network status unavailable` 语义，不透传 resolver、线程或系统错误细节。
 
+2026-06-20 追加：桌面壳分享缓存内部异常必须可观测。Tauri 桌面壳读写 `share.setTarget` 缓存失败时必须记录 `desktop share failed for ...` 日志；HostBridge 回包仍只暴露稳定 `share unavailable` 语义，不透传锁状态、内部缓存状态或 Rust 同步原语细节。
+
 2026-06-18 追加：H5 账号状态刷新开始消费 `app.reloadWebView`。用户登录成功、退出登录、其它身份边界变化或登录状态异常页点击重新尝试时，`AuthGate` 会优先请求 Expo 壳刷新当前 WebView；宿主未声明或刷新失败时再回退浏览器刷新，避免在移动壳内绕过受控容器刷新入口。
 
 2026-06-18 追加：移动壳 WebView 内容 / 渲染进程终止时复用同一受控刷新路径。iOS `onContentProcessDidTerminate` 和 Android `onRenderProcessGone` 只调用当前 `react-native-webview` 的 `reload()`，不改写 H5 URL、不注入额外脚本、不新增宿主恢复页面，避免系统回收 WebView 进程后留下空白容器。