diff --git a/src/admin/hooks/usePlanWork.ts b/src/admin/hooks/usePlanWork.ts
index 55294cd..2279cb7 100644
--- a/src/admin/hooks/usePlanWork.ts
+++ b/src/admin/hooks/usePlanWork.ts
@@ -30,6 +30,28 @@ function addDays(d: Date, n: number): Date {
   return r;
 }
 
+async function apiCall(
+  url: string,
+  options: RequestInit = {},
+): Promise<unknown> {
+  const res = await apiFetch(url, options);
+  if (!res.ok) {
+    let message = "Chyba serveru";
+    try {
+      const body = await res.json();
+      if (body && typeof body.error === "string") message = body.error;
+    } catch {
+      // body wasn't JSON; use default
+    }
+    throw new Error(message);
+  }
+  try {
+    return await res.json();
+  } catch {
+    return null;
+  }
+}
+
 export interface UsePlanWorkArgs {
   initialDate?: Date;
   canEdit: boolean;
@@ -72,7 +94,7 @@ export function usePlanWork({ initialDate, canEdit }: UsePlanWorkArgs) {
   // --- Mutations ---
   const createEntry = useMutation({
     mutationFn: (body: any) =>
-      apiFetch("/api/admin/plan/entries", {
+      apiCall("/api/admin/plan/entries", {
         method: "POST",
         body: JSON.stringify(body),
         headers: { "Content-Type": "application/json" },
@@ -90,7 +112,7 @@ export function usePlanWork({ initialDate, canEdit }: UsePlanWorkArgs) {
       body: any;
       force?: boolean;
     }) =>
-      apiFetch(`/api/admin/plan/entries/${id}${force ? "?force=1" : ""}`, {
+      apiCall(`/api/admin/plan/entries/${id}${force ? "?force=1" : ""}`, {
         method: "PATCH",
         body: JSON.stringify(body),
         headers: { "Content-Type": "application/json" },
@@ -100,7 +122,7 @@ export function usePlanWork({ initialDate, canEdit }: UsePlanWorkArgs) {
 
   const deleteEntry = useMutation({
     mutationFn: ({ id, force }: { id: number; force?: boolean }) =>
-      apiFetch(`/api/admin/plan/entries/${id}${force ? "?force=1" : ""}`, {
+      apiCall(`/api/admin/plan/entries/${id}${force ? "?force=1" : ""}`, {
         method: "DELETE",
       }),
     onSuccess: invalidate,
@@ -108,7 +130,7 @@ export function usePlanWork({ initialDate, canEdit }: UsePlanWorkArgs) {
 
   const createOverride = useMutation({
     mutationFn: (body: any) =>
-      apiFetch("/api/admin/plan/overrides", {
+      apiCall("/api/admin/plan/overrides", {
         method: "POST",
         body: JSON.stringify(body),
         headers: { "Content-Type": "application/json" },
@@ -126,7 +148,7 @@ export function usePlanWork({ initialDate, canEdit }: UsePlanWorkArgs) {
       body: any;
       force?: boolean;
     }) =>
-      apiFetch(`/api/admin/plan/overrides/${id}${force ? "?force=1" : ""}`, {
+      apiCall(`/api/admin/plan/overrides/${id}${force ? "?force=1" : ""}`, {
         method: "PATCH",
         body: JSON.stringify(body),
         headers: { "Content-Type": "application/json" },
@@ -136,7 +158,7 @@ export function usePlanWork({ initialDate, canEdit }: UsePlanWorkArgs) {
 
   const deleteOverride = useMutation({
     mutationFn: ({ id, force }: { id: number; force?: boolean }) =>
-      apiFetch(`/api/admin/plan/overrides/${id}${force ? "?force=1" : ""}`, {
+      apiCall(`/api/admin/plan/overrides/${id}${force ? "?force=1" : ""}`, {
         method: "DELETE",
       }),
     onSuccess: invalidate,