Merge dev into main (v0.54.0)

CHANGELOG.md

@@ -6,6 +6,16 @@ Das Format folgt [Keep a Changelog](https://keepachangelog.com/de/1.1.0/), die V
 
 ## [Unreleased]
 
+## [0.54.0] - 2026-11-02
+
+### Added
+- KI-Agenten können über MCP Unteraufgaben anlegen, abhaken, wieder öffnen, umbenennen und entfernen (`add_subtask`, `update_subtask`). Dafür reicht das Recht „Aufgaben ändern“; ist die Aufgabe mit einer Notiz verknüpft, ziehen die Checkboxen dort mit.
+- Am Handy lässt sich die Liste über den Titel oben wechseln: Ein Tipp auf den Namen der offenen Aufgabenliste bzw. Liste klappt alle Listen mit ihren Zählern auf.
+
+### Fixed
+- Notizen: Beim Klick in einen Punkt wurde die Zeile ein paar Pixel höher, sodass alles darunter kurz nach unten sprang.
+- Aufgaben-Details am Handy: Die Herkunfts-Badge eines API-Schlüssels ragte über den Knopf „Beobachten“. Am Handy steht die Herkunft jetzt nur noch unten; der Knopf „Beobachten“ ist so hoch wie die Knöpfe daneben.
+
 ## [0.53.0] - 2026-11-01
 
 ### Added
@@ -797,7 +807,8 @@ Das Format folgt [Keep a Changelog](https://keepachangelog.com/de/1.1.0/), die V
 - Geteilte Listen (Einkaufs-, Pack- und Checklisten) mit `#Kategorie`-Gruppierung, Mengenangaben und Echtzeit-Abhaken.
 - Benutzer-, Gruppen- und Admin-Verwaltung (Ersteinrichtungs-Assistent, Einladungscodes, Profilbilder, persönliche API-Keys & Webhook-Ingest `/api/v1/webhooks/ingest`, JSON-Datenexport) sowie CSS-Theme-Engine mit 4 Themes (`Dark`, `Light`, `High Contrast`, `Soft`) und PWA-Unterstützung.
 
-[Unreleased]: https://git.dsit.me/sandrodach/MindSift/compare/v0.53.0...dev
+[Unreleased]: https://git.dsit.me/sandrodach/MindSift/compare/v0.54.0...dev
+[0.54.0]: https://git.dsit.me/sandrodach/MindSift/compare/v0.53.0...v0.54.0
 [0.53.0]: https://git.dsit.me/sandrodach/MindSift/compare/v0.52.0...v0.53.0
 [0.52.0]: https://git.dsit.me/sandrodach/MindSift/compare/v0.51.0...v0.52.0
 [0.51.0]: https://git.dsit.me/sandrodach/MindSift/compare/v0.50.0...v0.51.0

Doku/api/rest.md

@@ -94,6 +94,8 @@ Betreiber können MCP abschalten (`MCP_ENABLED=false` oder Schalter in der Admin
 | `create_task` | `tasks:write` | Aufgabe anlegen (`content`, `taskListId`, `priority`, `dueDate`, `notes`); Quelle `agent` |
 | `update_task` | `tasks:write` | Felder ändern (`content`, `isCompleted`, `dueDate`, `priority`, `notes`, `kanbanStatus`, `taskListId`, `tags`) |
 | `complete_task` | `tasks:write` | Abhaken (`completed` false = wieder öffnen) |
+| `add_subtask` | `tasks:write` | Unteraufgabe anhängen (`taskId`, `title`) |
+| `update_subtask` | `tasks:write` | Unteraufgabe abhaken (`completed`), umbenennen (`title`) oder entfernen (`delete`) |
 | `delete_task` | `tasks:write` | Aufgabe löschen (z. B. versehentlich angelegte); sie kommt in den Papierkorb der Aufgaben |
 | `list_lists` | `lists:read` | Geteilte Listen mit offenen Einträgen |
 | `create_list` | `lists:write` | Liste anlegen (`title`, `icon`, `listType` shopping/checklist/vacation) |

Doku/ui-patterns.md

@@ -77,6 +77,14 @@ Komponente: [OriginBadge.tsx](../frontend/src/components/OriginBadge.tsx)
 - Höchstens eine Badge pro Eintrag: der Schlüssel, der angelegt hat, sonst der, der zuletzt geändert hat. Sie bleibt dauerhaft, auch nach eigenem Bearbeiten und nach der Triage.
 - Details (angelegt / zuletzt geändert, mit Schlüssel und Zeit) per Mouseover und per Tippen (kleines Info-Fenster, am Handy mit vergrößerter Trefferfläche); in der Aufgaben-Detailansicht stehen sie zusätzlich unten (`originDetails`). Ein Tipp auf die Badge öffnet nie den Eintrag.
 - Größen: `sm` in Aufgabenzeilen, Inbox-Liste und Detailansicht, `xs` auf Kanban-Karten und in Listen, `md` auf den Triage-Karten.
+- In der Aufgaben-Detailansicht steht die Badge am Handy nicht im Kopf (kein Platz neben den Knöpfen); dort zeigen nur die Details unten die Herkunft.
+
+## Liste wechseln (Handy)
+
+Komponente: [ListSwitcher.tsx](../frontend/src/components/ListSwitcher.tsx)
+
+- In der Kopfleiste am Handy (Aufgaben, Listen) ist der Titel der offenen Liste ein Knopf mit Pfeil. Ein Tipp klappt alle Listen auf, mit Icon, Zähler (`CountBadge`, `muted`) und Haken an der offenen; ein Tipp auf eine Liste wechselt dorthin.
+- Schließt bei Tipp daneben und mit Escape. Am Desktop bleiben die Reiter über der Liste.
 
 ## Mikrofon in Eingabezeilen
 

README.md

@@ -6,7 +6,7 @@
 [![Self-Hosted](https://img.shields.io/badge/100%25-Self--Hosted-2563eb?style=flat-square)](#)
 [![Docker](https://img.shields.io/badge/Deployment-Single%20Container-2496ed?style=flat-square&logo=docker&logoColor=white)](#-schnellstart)
 [![SQLite](https://img.shields.io/badge/Daten-SQLite-003b57?style=flat-square&logo=sqlite&logoColor=white)](#-deine-daten-gehören-dir)
-[![Version](https://img.shields.io/badge/Version-v0.53.0-16a34a?style=flat-square)](CHANGELOG.md)
+[![Version](https://img.shields.io/badge/Version-v0.54.0-16a34a?style=flat-square)](CHANGELOG.md)
 
 **MindSift** ist eine selbst gehostete Schaltstelle für spontane Gedanken, Aufgaben mit Kanban-Board, hierarchische Outliner-Notizen, die mehrere Personen gleichzeitig bearbeiten können, und gemeinsame Listen. Alles läuft als ein einzelner Container mit eingebetteter SQLite-Datenbank, auf deinem eigenen Server.
 

frontend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "mindsift-frontend",
-  "version": "0.53.0",
+  "version": "0.54.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "mindsift-frontend",
-      "version": "0.53.0",
+      "version": "0.54.0",
       "license": "AGPL-3.0-only",
       "dependencies": {
         "@fontsource-variable/inter": "5.3.0",

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "mindsift-frontend",
   "private": true,
-  "version": "0.53.0",
+  "version": "0.54.0",
   "license": "AGPL-3.0-only",
   "type": "module",
   "scripts": {

frontend/src/components/ListSwitcher.tsx

@@ -0,0 +1,87 @@
+import React, { useEffect, useRef, useState } from 'react';
+import { Check, ChevronDown } from 'lucide-react';
+import { CountBadge } from './CountBadge';
+
+export interface ListSwitcherItem {
+  id: string;
+  title: string;
+  icon?: string;
+  count?: number;
+}
+
+interface ListSwitcherProps {
+  // Shown on the button: the list that is open now
+  label: string;
+  items: ListSwitcherItem[];
+  activeId: string;
+  onSelect: (id: string) => void;
+}
+
+// Title of the open list in the phone header (Doku/ui-patterns.md): a tap opens all lists to switch to
+export const ListSwitcher: React.FC<ListSwitcherProps> = ({ label, items, activeId, onSelect }) => {
+  const [open, setOpen] = useState(false);
+  const ref = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    if (!open) return;
+    const close = (e: Event) => {
+      if (ref.current && !ref.current.contains(e.target as Node)) setOpen(false);
+    };
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') setOpen(false);
+    };
+    document.addEventListener('pointerdown', close);
+    document.addEventListener('keydown', onKey);
+    return () => {
+      document.removeEventListener('pointerdown', close);
+      document.removeEventListener('keydown', onKey);
+    };
+  }, [open]);
+
+  return (
+    <div ref={ref} className="relative min-w-0">
+      <button
+        type="button"
+        onClick={() => setOpen((o) => !o)}
+        aria-haspopup="listbox"
+        aria-expanded={open}
+        title="Liste wechseln"
+        className="h-11 -my-1 max-w-full flex items-center gap-1 text-sm font-semibold text-main cursor-pointer"
+      >
+        <span className="truncate">{label}</span>
+        <ChevronDown className={`w-4 h-4 text-muted flex-shrink-0 transition-transform ${open ? 'rotate-180' : ''}`} />
+      </button>
+      {open && (
+        <div
+          role="listbox"
+          aria-label="Liste wechseln"
+          className="absolute left-0 top-full mt-1 z-40 w-72 max-w-[calc(100vw-2rem)] max-h-[60vh] overflow-y-auto py-1 bg-panel border border-border rounded-card shadow-panel"
+        >
+          {items.map((item) => {
+            const active = item.id === activeId;
+            return (
+              <button
+                key={item.id}
+                type="button"
+                role="option"
+                aria-selected={active}
+                onClick={() => {
+                  setOpen(false);
+                  if (!active) onSelect(item.id);
+                }}
+                className={`w-full h-11 px-3 flex items-center gap-2 text-left text-sm cursor-pointer hover:bg-panel-elevated ${
+                  active ? 'text-main font-semibold' : 'text-muted'
+                }`}
+              >
+                {item.icon && <span className="flex-shrink-0">{item.icon}</span>}
+                <span className="truncate flex-1">{item.title}</span>
+                <CountBadge count={item.count} />
+                {active && <Check className="w-4 h-4 text-accent flex-shrink-0" />}
+              </button>
+            );
+          })}
+        </div>
+      )}
+    </div>
+  );
+};

frontend/src/components/__tests__/ListSwitcher.test.tsx

@@ -0,0 +1,44 @@
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { ListSwitcher } from '../ListSwitcher';
+
+const items = [
+  { id: 'a', title: 'Haushalt', icon: '🏠', count: 3 },
+  { id: 'b', title: 'Arbeit' },
+];
+
+describe('ListSwitcher', () => {
+  it('opens all lists on a tap and switches to the chosen one', () => {
+    const onSelect = vi.fn();
+    render(<ListSwitcher label="🏠 Haushalt" items={items} activeId="a" onSelect={onSelect} />);
+    expect(screen.queryByRole('listbox')).toBeNull();
+
+    fireEvent.click(screen.getByRole('button', { name: /Haushalt/ }));
+    const options = screen.getAllByRole('option');
+    expect(options).toHaveLength(2);
+    expect(options[0].getAttribute('aria-selected')).toBe('true');
+
+    fireEvent.click(screen.getByRole('option', { name: /Arbeit/ }));
+    expect(onSelect).toHaveBeenCalledWith('b');
+    expect(screen.queryByRole('listbox')).toBeNull();
+  });
+
+  it('closes without a change on the open list, Escape or a tap outside', () => {
+    const onSelect = vi.fn();
+    render(<ListSwitcher label="🏠 Haushalt" items={items} activeId="a" onSelect={onSelect} />);
+    const button = screen.getByRole('button', { name: /Haushalt/ });
+
+    fireEvent.click(button);
+    fireEvent.click(screen.getByRole('option', { name: /Haushalt/ }));
+    expect(screen.queryByRole('listbox')).toBeNull();
+
+    fireEvent.click(button);
+    fireEvent.keyDown(document, { key: 'Escape' });
+    expect(screen.queryByRole('listbox')).toBeNull();
+
+    fireEvent.click(button);
+    fireEvent.pointerDown(document.body);
+    expect(screen.queryByRole('listbox')).toBeNull();
+    expect(onSelect).not.toHaveBeenCalled();
+  });
+});

frontend/src/features/lists/SharedListsView.tsx

@@ -16,6 +16,7 @@ import { OFFLINE_ITEM_PREFIX, pendingListItems } from '../../lib/offline';
 import { UnifiedShareModal } from '../../components/UnifiedShareModal';
 import { AvatarStack, AvatarPerson } from '../../components/AvatarStack';
 import { CountBadge } from '../../components/CountBadge';
+import { ListSwitcher } from '../../components/ListSwitcher';
 import { OriginBadge } from '../../components/OriginBadge';
 import { VoiceInputButton } from '../../components/VoiceInputButton';
 import { FormSheet } from '../../components/FormSheet';
@@ -1170,9 +1171,21 @@ export const SharedListsView: React.FC<SharedListsViewProps> = ({ onRefreshGloba
       {/* Same height with or without the 36 px share button (Tasks, Shopping lists) */}
       <div className="flex sm:hidden items-center justify-between gap-2 px-3 py-2 min-h-[54px] rounded-btn bg-panel border border-border !mt-0">
         <div className="flex items-center gap-2 min-w-0">
-          <span className="text-sm font-semibold text-main truncate">
+          {activeList ? (
-            {activeList ? [activeList.icon, activeList.title].filter(Boolean).join(' ') : '🛒 Einkaufsliste'}
+            <ListSwitcher
-          </span>
+              label={[activeList.icon, activeList.title].filter(Boolean).join(' ')}
+              items={lists.map((lst) => ({
+                id: lst.id,
+                title: lst.title,
+                icon: lst.icon,
+                count: deduplicateItems(lst.items || []).filter((i) => !i.isCompleted).length,
+              }))}
+              activeId={activeList.id}
+              onSelect={setActiveListId}
+            />
+          ) : (
+            <span className="text-sm font-semibold text-main truncate">🛒 Einkaufsliste</span>
+          )}
           {openItems.length > 0 && (
             <span className="badge-neutral text-[11px] flex-shrink-0">
               {openItems.length} offen

frontend/src/features/settings/ApiKeysPanel.tsx

@@ -632,7 +632,8 @@ http_headers = { "X-API-Key" = "${exampleToken}" }`
               Werkzeuge: <code className="font-mono">list_task_lists</code>, <code className="font-mono">create_task_list</code>,{' '}
               <code className="font-mono">list_tasks</code>, <code className="font-mono">get_task</code>,{' '}
               <code className="font-mono">create_task</code>, <code className="font-mono">update_task</code>,{' '}
-              <code className="font-mono">complete_task</code>, <code className="font-mono">delete_task</code>,{' '}
+              <code className="font-mono">complete_task</code>, <code className="font-mono">add_subtask</code>,{' '}
+              <code className="font-mono">update_subtask</code>, <code className="font-mono">delete_task</code>,{' '}
               <code className="font-mono">list_lists</code>, <code className="font-mono">create_list</code>,{' '}
               <code className="font-mono">get_list</code>, <code className="font-mono">add_list_item</code>,{' '}
               <code className="font-mono">check_list_item</code>, <code className="font-mono">update_list_item</code>,{' '}

frontend/src/features/triage/TaskDetailModal.tsx

@@ -236,7 +236,8 @@ const TaskDetailModalContent: React.FC<TaskDetailModalProps & { task: Thought }>
             >
               <Check className="w-3.5 h-3.5 stroke-[3]" />
             </button>
-            <span className="text-xs font-semibold text-main truncate">
+            {/* Phones: squeezed to a single letter next to the buttons, so left out */}
+            <span className="hidden sm:inline text-xs font-semibold text-main truncate">
               {readOnly ? 'Aufgabe ansehen' : task.isCompleted ? 'Erledigte Aufgabe' : 'Aufgabe bearbeiten'}
             </span>
             {readOnly && (
@@ -245,7 +246,10 @@ const TaskDetailModalContent: React.FC<TaskDetailModalProps & { task: Thought }>
                 <span>Nur Lesen</span>
               </span>
             )}
-            <OriginBadge origin={task.origin} createdAt={task.createdAt} />
+            {/* Phones: no room next to the buttons; the details stand at the bottom anyway */}
+            <span className="hidden sm:inline-flex min-w-0">
+              <OriginBadge origin={task.origin} createdAt={task.createdAt} />
+            </span>
           </div>
 
           <div className="flex items-center gap-1.5">
@@ -254,7 +258,7 @@ const TaskDetailModalContent: React.FC<TaskDetailModalProps & { task: Thought }>
               onClick={handleToggleWatch}
               disabled={watchBusy}
               title={isWatching ? 'Nicht mehr beobachten' : 'Beobachten'}
-              className={`btn-action min-h-[44px] sm:min-h-0 h-11 sm:h-7 px-2.5 sm:px-2 text-xs flex items-center gap-1.5 ${
+              className={`btn-action min-h-[38px] sm:min-h-0 h-9 sm:h-7 px-2.5 sm:px-2 text-xs flex items-center gap-1.5 ${
                 isWatching ? 'border-accent text-accent' : ''
               }`}
             >

frontend/src/features/triage/TasksView.tsx

@@ -40,6 +40,7 @@ import { VoiceInputButton } from '../../components/VoiceInputButton';
 import { ManageColumnsModal, DEFAULT_KANBAN_COLUMNS, columnDotClass } from './ManageColumnsModal';
 import { AvatarStack, AvatarPerson } from '../../components/AvatarStack';
 import { CountBadge } from '../../components/CountBadge';
+import { ListSwitcher } from '../../components/ListSwitcher';
 import { FormSheet } from '../../components/FormSheet';
 import { EmojiIconButton } from '../../components/EmojiIconButton';
 import { useMobileActions } from '../../context/MobileActionContext';
@@ -1953,9 +1954,15 @@ export const TasksView: React.FC<TasksViewProps> = ({
       {/* Same height with or without the 36 px share button (Tasks, Shopping lists) */}
       <div className="flex sm:hidden items-center justify-between gap-2 px-3 py-2 min-h-[54px] rounded-btn bg-panel border border-border !mt-0">
         <div className="flex items-center gap-2 min-w-0">
-          <span className="text-sm font-semibold text-main truncate">
+          <ListSwitcher
-            {currentSelectedList ? [currentSelectedList.icon, currentSelectedList.title].filter(Boolean).join(' ') : '📋 Alle Aufgaben'}
+            label={currentSelectedList ? [currentSelectedList.icon, currentSelectedList.title].filter(Boolean).join(' ') : '📋 Alle Aufgaben'}
-          </span>
+            items={[
+              { id: 'all', title: 'Alle Aufgaben', icon: '📋', count: openTasksCount },
+              ...safeTaskLists.map((tl) => ({ id: tl.id, title: tl.title, icon: tl.icon, count: tl.tasksCount })),
+            ]}
+            activeId={selectedListId}
+            onSelect={setSelectedListId}
+          />
           <span className="badge-neutral text-[11px] flex-shrink-0">
             {viewMode === 'kanban'
               ? 'Kanban'

frontend/src/features/workspace/OutlinerBlock.tsx

@@ -1437,6 +1437,8 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
               )}
             </div>
 
+            {/* Display block: inline, the focused field would sit on a text baseline and leave a gap below
+                it, so the row grew by a few pixels on every click */}
             <textarea
               ref={(el) => {
                 textareaRef.current = el;
@@ -1482,7 +1484,7 @@ export const OutlinerBlock: React.FC<OutlinerBlockProps> = ({
                   }
                 }
               }}
-              className={`w-full min-h-[1.5rem] resize-none overflow-hidden bg-transparent border-0 focus:outline-none focus:ring-0 leading-relaxed whitespace-pre-wrap break-words [overflow-wrap:anywhere] ${
+              className={`block w-full min-h-[1.5rem] resize-none overflow-hidden bg-transparent border-0 focus:outline-none focus:ring-0 leading-relaxed whitespace-pre-wrap break-words [overflow-wrap:anywhere] ${
                 activeFocus ? 'relative z-0 text-main' : 'absolute inset-0 text-transparent selection:text-transparent pointer-events-none'
               } ${
                 block.type === 'h1'

internal/api/mcp.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"sort"
 	"strings"
+	"time"
 
 	"github.com/sandrodach/mindsift/internal/auth"
 	"github.com/sandrodach/mindsift/internal/domain"
@@ -134,8 +135,9 @@ func (s *Server) handleMCP(w http.ResponseWriter, r *http.Request) {
 			"capabilities":    map[string]interface{}{"tools": map[string]interface{}{}},
 			"serverInfo":      map[string]string{"name": "MindSift", "version": mcpServerVersion},
 			"instructions": "MindSift is a personal notes, tasks and lists app. Use list_task_lists and list_tasks " +
-				"to see open tasks, complete_task to check one off, list_lists/get_list for shopping and other " +
+				"to see open tasks, complete_task to check one off, add_subtask/update_subtask for a task's " +
-				"lists and check_list_item to tick items, list_notes/get_note to read notes and create_note for a " +
+				"checklist, list_lists/get_list for shopping and other lists and check_list_item to tick items, " +
+				"list_notes/get_note to read notes and create_note for a " +
 				"new one. IDs come from the list tools; never guess them. Tasks and list items you create or " +
 				"change show the user a badge with the name of your API key.",
 		}, nil)
@@ -604,6 +606,98 @@ var mcpTools = []mcpTool{
 			return toTaskView(t), nil
 		},
 	},
+	{
+		Name:        "add_subtask",
+		Description: "Add a subtask (checklist item) to a task. Returns the task with all its subtasks.",
+		Scope:       storage.ScopeTasksWrite,
+		Schema: schema([]string{"taskId", "title"}, map[string]interface{}{
+			"taskId": prop("string", "Task id"),
+			"title":  prop("string", "Subtask text"),
+		}),
+		run: func(s *Server, userID string, actor *apiActor, args json.RawMessage) (interface{}, error) {
+			var a struct {
+				TaskID string `json:"taskId"`
+				Title  string `json:"title"`
+			}
+			if err := decodeArgs(args, &a); err != nil {
+				return nil, err
+			}
+			title := strings.TrimSpace(a.Title)
+			if title == "" {
+				return nil, errors.New("'title' darf nicht leer sein")
+			}
+			t, err := s.store.GetThoughtByID(userID, a.TaskID)
+			if err != nil || t == nil {
+				return nil, errors.New("Aufgabe nicht gefunden")
+			}
+			subs := append(append([]domain.SubTask{}, t.Subtasks...), domain.SubTask{
+				ID: domain.NewID("st"), Title: title, CreatedAt: time.Now().UTC().Format(time.RFC3339),
+			})
+			updated, err := s.updateTask(userID, a.TaskID, taskPatch{Subtasks: &subs, actor: actor})
+			if err != nil {
+				return nil, err
+			}
+			return toTaskView(updated), nil
+		},
+	},
+	{
+		Name:        "update_subtask",
+		Description: "Tick a subtask off (completed), reopen it (completed=false), rename it (title) or remove it (delete=true).",
+		Scope:       storage.ScopeTasksWrite,
+		Schema: schema([]string{"taskId", "subtaskId"}, map[string]interface{}{
+			"taskId":    prop("string", "Task id"),
+			"subtaskId": prop("string", "Subtask id from get_task"),
+			"completed": prop("boolean", "true = done"),
+			"title":     prop("string", "New text"),
+			"delete":    prop("boolean", "true = remove the subtask"),
+		}),
+		run: func(s *Server, userID string, actor *apiActor, args json.RawMessage) (interface{}, error) {
+			var a struct {
+				TaskID    string  `json:"taskId"`
+				SubtaskID string  `json:"subtaskId"`
+				Completed *bool   `json:"completed"`
+				Title     *string `json:"title"`
+				Delete    bool    `json:"delete"`
+			}
+			if err := decodeArgs(args, &a); err != nil {
+				return nil, err
+			}
+			if a.Title != nil && strings.TrimSpace(*a.Title) == "" {
+				return nil, errors.New("'title' darf nicht leer sein")
+			}
+			t, err := s.store.GetThoughtByID(userID, a.TaskID)
+			if err != nil || t == nil {
+				return nil, errors.New("Aufgabe nicht gefunden")
+			}
+			subs := make([]domain.SubTask, 0, len(t.Subtasks))
+			found := false
+			for _, st := range t.Subtasks {
+				if st.ID != a.SubtaskID {
+					subs = append(subs, st)
+					continue
+				}
+				found = true
+				if a.Delete {
+					continue
+				}
+				if a.Completed != nil {
+					st.IsCompleted = *a.Completed
+				}
+				if a.Title != nil {
+					st.Title = strings.TrimSpace(*a.Title)
+				}
+				subs = append(subs, st)
+			}
+			if !found {
+				return nil, errors.New("Unteraufgabe nicht gefunden")
+			}
+			updated, err := s.updateTask(userID, a.TaskID, taskPatch{Subtasks: &subs, actor: actor})
+			if err != nil {
+				return nil, err
+			}
+			return toTaskView(updated), nil
+		},
+	},
 	{
 		Name:        "delete_task",
 		Description: "Delete a task, e.g. one created by mistake: it goes to the task trash, where the user can restore it. Prefer complete_task for work that is done.",

internal/api/mcp_test.go

@@ -289,6 +289,63 @@ func TestMCPCreateDeleteAndOrigin(t *testing.T) {
 	}
 }
 
+// Agents manage a task's subtasks one at a time; the rest of the checklist stays as it is.
+func TestMCPSubtasks(t *testing.T) {
+	srv, store, token := setupTestServer(t)
+	router := srv.Router()
+	claims, _ := auth.ValidateToken(testJWTSecret, token)
+	key, _ := store.CreateAPIKey(claims.UserID, "Claude Code", []string{"tasks:read", "tasks:write"})
+	call := func(id int, name, args string) (map[string]interface{}, bool) {
+		t.Helper()
+		_, res := rpc(t, router, key.RawKey, fmt.Sprintf(`{"jsonrpc":"2.0","id":%d,"method":"tools/call","params":{"name":%q,"arguments":%s}}`, id, name, args))
+		result, isErr := callResult(t, res)
+		if isErr {
+			return result, true
+		}
+		return result["structuredContent"].(map[string]interface{}), false
+	}
+
+	task, _ := srv.createTask(claims.UserID, "Umzug", "", "manual", "", "", "", nil)
+	call(1, "add_subtask", `{"taskId":"`+task.ID+`","title":"Kartons kaufen"}`)
+	res, isErr := call(2, "add_subtask", `{"taskId":"`+task.ID+`","title":" Strom ummelden "}`)
+	if isErr {
+		t.Fatalf("add_subtask: %v", res)
+	}
+	subs := res["subtasks"].([]interface{})
+	if len(subs) != 2 || subs[1].(map[string]interface{})["title"] != "Strom ummelden" {
+		t.Fatalf("subtasks after adding: %v", subs)
+	}
+	first := subs[0].(map[string]interface{})["id"].(string)
+	second := subs[1].(map[string]interface{})["id"].(string)
+
+	call(3, "update_subtask", `{"taskId":"`+task.ID+`","subtaskId":"`+first+`","completed":true}`)
+	call(4, "update_subtask", `{"taskId":"`+task.ID+`","subtaskId":"`+second+`","title":"Strom und Gas ummelden"}`)
+	th, _ := store.GetThoughtByID(claims.UserID, task.ID)
+	if len(th.Subtasks) != 2 || !th.Subtasks[0].IsCompleted || th.Subtasks[1].IsCompleted || th.Subtasks[1].Title != "Strom und Gas ummelden" {
+		t.Fatalf("subtasks after updating: %+v", th.Subtasks)
+	}
+	if th.Origin == nil || th.Origin.ChangedVia != "mcp" {
+		t.Fatalf("subtask change should count as agent change: %+v", th.Origin)
+	}
+
+	call(5, "update_subtask", `{"taskId":"`+task.ID+`","subtaskId":"`+first+`","delete":true}`)
+	if th, _ = store.GetThoughtByID(claims.UserID, task.ID); len(th.Subtasks) != 1 || th.Subtasks[0].ID != second {
+		t.Fatalf("subtasks after deleting: %+v", th.Subtasks)
+	}
+
+	if _, isErr = call(6, "update_subtask", `{"taskId":"`+task.ID+`","subtaskId":"st_unknown","completed":true}`); !isErr {
+		t.Fatalf("unknown subtask must fail")
+	}
+	if _, isErr = call(7, "add_subtask", `{"taskId":"`+task.ID+`","title":"  "}`); !isErr {
+		t.Fatalf("empty title must fail")
+	}
+	other, _ := store.CreateUser("other@example.com", "hash", "Other", "member")
+	foreign, _ := store.CreateThoughtWithDetails(other.ID, "Fremd", "normal", "manual", "", "", "todo", "")
+	if _, isErr = call(8, "add_subtask", `{"taskId":"`+foreign.ID+`","title":"Spam"}`); !isErr {
+		t.Fatalf("key must not change foreign tasks")
+	}
+}
+
 // Operators can switch MCP off: in the admin settings, or fixed by MCP_ENABLED. OAuth goes with it.
 func TestMCPSwitchOff(t *testing.T) {
 	srv, _, session := setupTestServer(t)