diff --git a/webui/backend/tests/golden/__pycache__/test_ui_smoke_golden.cpython-313.pyc b/webui/backend/tests/golden/__pycache__/test_ui_smoke_golden.cpython-313.pyc
index 4bb3768..52200db 100644
Binary files a/webui/backend/tests/golden/__pycache__/test_ui_smoke_golden.cpython-313.pyc and b/webui/backend/tests/golden/__pycache__/test_ui_smoke_golden.cpython-313.pyc differ
diff --git a/webui/backend/tests/golden/test_ui_smoke_golden.py b/webui/backend/tests/golden/test_ui_smoke_golden.py
index ec09f9a..3ba8b38 100644
--- a/webui/backend/tests/golden/test_ui_smoke_golden.py
+++ b/webui/backend/tests/golden/test_ui_smoke_golden.py
@@ -40,6 +40,25 @@ class UiSmokeGoldenTest(unittest.TestCase):
                     return source[start : index + 1]
         self.fail(f"Expected closing brace for function {name}")
 
+    def _extract_async_js_function(self, source: str, name: str) -> str:
+        marker = f"async function {name}("
+        start = source.find(marker)
+        if start < 0:
+            self.fail(f"Expected async function {name} in app.js")
+        brace_start = source.find("{", start)
+        if brace_start < 0:
+            self.fail(f"Expected opening brace for async function {name}")
+        depth = 0
+        for index in range(brace_start, len(source)):
+            char = source[index]
+            if char == "{":
+                depth += 1
+            elif char == "}":
+                depth -= 1
+                if depth == 0:
+                    return source[start : index + 1]
+        self.fail(f"Expected closing brace for async function {name}")
+
     def _run_app_js_behavior_check(self, app_js: str) -> None:
         functions = "\n\n".join(
             [
@@ -592,6 +611,104 @@ class UiSmokeGoldenTest(unittest.TestCase):
         )
         self.assertEqual(result.returncode, 0, msg=result.stderr or result.stdout)
 
+    def _run_operation_start_behavior_check(self, app_js: str) -> None:
+        functions = "\n\n".join(
+            [
+                self._extract_js_function(app_js, "paneState"),
+                self._extract_js_function(app_js, "otherPane"),
+                self._extract_js_function(app_js, "defaultDestination"),
+                self._extract_async_js_function(app_js, "startCopySelected"),
+                self._extract_async_js_function(app_js, "executeMoveSelection"),
+            ]
+        )
+        script = textwrap.dedent(
+            f"""
+            const assert = (condition, message) => {{
+              if (!condition) {{
+                throw new Error(message);
+              }}
+            }};
+
+            let state = {{
+              activePane: "left",
+              panes: {{
+                left: {{
+                  currentPath: "storage1/source",
+                  selectedItems: [
+                    {{ path: "storage1/source/a.txt", kind: "file", name: "a.txt" }},
+                    {{ path: "storage1/source/b.txt", kind: "file", name: "b.txt" }},
+                  ],
+                }},
+                right: {{
+                  currentPath: "storage1/dest",
+                  selectedItems: [],
+                }},
+              }},
+              selectedTaskId: null,
+            }};
+
+            const apiCalls = [];
+            const statusMessages = [];
+            const errorCalls = [];
+            const refreshCalls = [];
+            const loadCalls = [];
+            const clearedSelection = [];
+
+            async function apiRequest(method, url, body) {{
+              apiCalls.push({{ method, url, body }});
+              return {{ task_id: "task-123", status: "queued" }};
+            }}
+            function setError() {{}}
+            function setActionError(action, err) {{ errorCalls.push({{ action, message: err.message }}); }}
+            function setStatus(message) {{ statusMessages.push(message); }}
+            async function refreshTasksSnapshot() {{ refreshCalls.push(true); }}
+            async function loadBrowsePane(pane) {{ loadCalls.push(pane); }}
+            function setSelectedItem(pane, value) {{ clearedSelection.push({{ pane, value }}); }}
+
+            {functions}
+
+            (async () => {{
+              await startCopySelected();
+              assert(apiCalls.length === 1, "Multi-select copy should issue one request");
+              assert(apiCalls[0].url === "/api/files/copy", "Copy should use copy endpoint");
+              assert(Array.isArray(apiCalls[0].body.sources), "Copy should send batch sources");
+              assert(apiCalls[0].body.sources.length === 2, "Copy batch should include all selected items");
+              assert(apiCalls[0].body.destination_base === "storage1/dest", "Copy batch should target destination base");
+              assert(state.selectedTaskId === "task-123", "Copy should store the created task id");
+              assert(refreshCalls.length === 1, "Copy should refresh task snapshot once");
+              assert(statusMessages.includes("Copy: operation started"), "Copy should report operation start");
+
+              apiCalls.length = 0;
+              refreshCalls.length = 0;
+              statusMessages.length = 0;
+              state.selectedTaskId = null;
+
+              await executeMoveSelection("storage1/dest");
+              assert(apiCalls.length === 1, "Multi-select move should issue one request");
+              assert(apiCalls[0].url === "/api/files/move", "Move should use move endpoint");
+              assert(Array.isArray(apiCalls[0].body.sources), "Move should send batch sources");
+              assert(apiCalls[0].body.sources.length === 2, "Move batch should include all selected items");
+              assert(apiCalls[0].body.destination_base === "storage1/dest", "Move batch should target destination base");
+              assert(state.selectedTaskId === "task-123", "Move should store the created task id");
+              assert(refreshCalls.length === 1, "Move should refresh task snapshot once");
+              assert(statusMessages.includes("Move: operation started"), "Move should report operation start");
+              assert(clearedSelection.length === 1 && clearedSelection[0].pane === "left", "Move batch should clear source selection once");
+              assert(errorCalls.length === 0, "Batch operation start should not emit action errors");
+            }})().catch((error) => {{
+              console.error(error);
+              process.exit(1);
+            }});
+            """
+        )
+        result = subprocess.run(
+            ["node", "-e", script],
+            cwd="/workspace/webmanager-mvp",
+            capture_output=True,
+            text=True,
+            check=False,
+        )
+        self.assertEqual(result.returncode, 0, msg=result.stderr or result.stdout)
+
     def test_ui_mount_and_index_contains_expected_panels(self) -> None:
         mount = self._ui_mount()
         self.assertIsInstance(mount.app, StaticFiles)
@@ -1014,6 +1131,10 @@ class UiSmokeGoldenTest(unittest.TestCase):
         self.assertIn('startCopySelected();', app_js)
         self.assertIn('openF6Flow();', app_js)
         self.assertIn('deleteSelected();', app_js)
+        self.assertIn('sources: selectedItems.map((item) => item.path),', app_js)
+        self.assertIn('destination_base: baseDestination,', app_js)
+        self.assertIn('setStatus("Copy: operation started");', app_js)
+        self.assertIn('setStatus("Move: operation started");', app_js)
         self.assertIn('const confirmed = await openConfirmModal({', app_js)
         self.assertIn('title: selectedItems.length === 1 ? "Delete item?" : "Delete selected items?"', app_js)
         self.assertIn('title: "Discard unsaved changes?"', app_js)
@@ -1108,6 +1229,7 @@ class UiSmokeGoldenTest(unittest.TestCase):
         self.assertIn('input.setAttribute("webkitdirectory", "")', app_js)
         self.assertIn('await apiRequest("POST", "/api/files/mkdir", {', app_js)
         self.assertIn('await uploadFileRequest(targetPath, entry.file, overwrite);', app_js)
+        self._run_operation_start_behavior_check(app_js)
         self.assertIn('Folder upload: preparing', app_js)
         self.assertIn('Folder upload: ${uploadState.successfulCount} uploaded, ${uploadState.skippedCount} skipped', app_js)
         self.assertIn('async function handleUploadSelection(event)', app_js)
diff --git a/webui/html/app.js b/webui/html/app.js
index b6bd5fc..94df0d8 100644
--- a/webui/html/app.js
+++ b/webui/html/app.js
@@ -2874,28 +2874,30 @@ async function startCopySelected() {
   }
   const baseDestination = paneState(destinationPane).currentPath;
   setError("actions-error", "");
-  let successes = 0;
-  let failures = 0;
-  let firstError = null;
-  for (const item of selectedItems) {
-    const destination = defaultDestination(item.path, baseDestination);
-    try {
-      const result = await apiRequest("POST", "/api/files/copy", {
+  try {
+    let result;
+    if (selectedItems.length > 1) {
+      result = await apiRequest("POST", "/api/files/copy", {
+        sources: selectedItems.map((item) => item.path),
+        destination_base: baseDestination,
+      });
+      setStatus("Copy: operation started");
+    } else {
+      const item = selectedItems[0];
+      const destination = defaultDestination(item.path, baseDestination);
+      result = await apiRequest("POST", "/api/files/copy", {
         source: item.path,
         destination,
       });
-      state.selectedTaskId = result.task_id;
-      await refreshTasksSnapshot();
-      successes += 1;
-    } catch (err) {
-      failures += 1;
-      if (!firstError) {
-        firstError = `${item.path}: ${err.message}`;
-      }
+      setStatus("Copy: started");
     }
+    state.selectedTaskId = result.task_id;
+    await refreshTasksSnapshot();
+  } catch (err) {
+    setActionError("Copy", err);
+    return;
   }
   await Promise.all([loadBrowsePane("left"), loadBrowsePane("right")]);
-  showActionSummary("Copy", successes, failures, firstError);
 }
 
 async function startMoveSelected() {
@@ -2908,10 +2910,9 @@ async function executeMoveSelection(baseDestination) {
   if (selectedItems.length === 0) {
     return;
   }
-  const allFiles = selectedItems.every((item) => item.kind === "file");
   setError("actions-error", "");
 
-  if (!allFiles) {
+  if (selectedItems.length > 1) {
     const result = await apiRequest("POST", "/api/files/move", {
       sources: selectedItems.map((item) => item.path),
       destination_base: baseDestination,
@@ -2920,36 +2921,25 @@ async function executeMoveSelection(baseDestination) {
     await refreshTasksSnapshot();
     setSelectedItem(sourcePane, null);
     await Promise.all([loadBrowsePane("left"), loadBrowsePane("right")]);
-    setStatus("Move: batch started");
+    setStatus("Move: operation started");
     return;
   }
 
-  let successes = 0;
-  let failures = 0;
-  let firstError = null;
-  for (const item of selectedItems) {
-    const destination = defaultDestination(item.path, baseDestination);
-    try {
-      if (item.kind !== "file") {
-        throw new Error("Only files are supported for move");
-      }
-      const result = await apiRequest("POST", "/api/files/move", {
-        source: item.path,
-        destination,
-      });
-      state.selectedTaskId = result.task_id;
-      await refreshTasksSnapshot();
-      successes += 1;
-    } catch (err) {
-      failures += 1;
-      if (!firstError) {
-        firstError = `${item.path}: ${err.message}`;
-      }
-    }
+  const item = selectedItems[0];
+  const destination = defaultDestination(item.path, baseDestination);
+  if (item.kind !== "file") {
+    setActionError("Move", new Error("Only files are supported for single-item move"));
+    return;
   }
+  const result = await apiRequest("POST", "/api/files/move", {
+    source: item.path,
+    destination,
+  });
+  state.selectedTaskId = result.task_id;
+  await refreshTasksSnapshot();
   setSelectedItem(sourcePane, null);
   await Promise.all([loadBrowsePane("left"), loadBrowsePane("right")]);
-  showActionSummary("Move", successes, failures, firstError);
+  setStatus("Move: started");
 }
 
 async function addBookmark() {