Add automatic tag collections

core/admin.py

@@ -9,8 +9,9 @@ class CollectionSectionInline(admin.TabularInline):
 
 @admin.register(Collection)
 class CollectionAdmin(admin.ModelAdmin):
-    list_display = ('title', 'visibility', 'team', 'owner', 'updated_at')
-    list_filter = ('visibility', 'team')
+    list_display = ('title', 'mode', 'visibility', 'team', 'owner', 'updated_at')
+    list_filter = ('mode', 'visibility', 'team')
+    filter_horizontal = ('filter_tags',)
     inlines = [CollectionSectionInline]
 
 

core/forms.py

@@ -1,6 +1,7 @@
 from django import forms
 from django.contrib.auth.forms import UserCreationForm
 from django.contrib.auth.models import User
+from django.db.models import Q
 from django.utils.translation import gettext_lazy as _
 from .models import ApiKey, Attachment, Collection, Item, Kanban, Tag, Team, TeamInvite, UserInvite, UserPreference
 
@@ -134,34 +135,47 @@ class KanbanForm(forms.ModelForm):
 
 
 class CollectionForm(forms.ModelForm):
+    team = forms.ModelChoiceField(queryset=Team.objects.none(), required=False, label=_('Team'), widget=forms.Select(attrs={'class': 'form-select'}))
+
     def __init__(self, *args, user=None, **kwargs):
         super().__init__(*args, **kwargs)
+        self.fields['visibility'].choices = [
+            (Item.Visibility.PRIVATE, _('Private')),
+            (Item.Visibility.PUBLIC, _('Public')),
+        ]
         if user and user.is_authenticated:
-            team_slugs = user.team_memberships.values_list('team__slug', flat=True)
-            self.fields['tags'].queryset = Tag.objects.filter(name__in=team_slugs).order_by('name')
+            team_ids = user.team_memberships.values_list('team_id', flat=True)
+            self.fields['team'].queryset = Team.objects.filter(pk__in=team_ids).order_by('name')
+            self.fields['team'].initial = self.instance.team_id if self.instance and self.instance.pk else None
+            item_scope = Q(items__owner=user) | Q(items__team_id__in=team_ids)
+            team_slugs = Team.objects.values_list('slug', flat=True)
+            self.fields['filter_tags'].queryset = Tag.objects.filter(item_scope).exclude(name__in=team_slugs).distinct().order_by('name')
         else:
-            self.fields['tags'].queryset = Tag.objects.none()
+            self.fields['team'].queryset = Team.objects.none()
+            self.fields['filter_tags'].queryset = Tag.objects.none()
 
-    def clean_tags(self):
-        tags = self.cleaned_data['tags']
-        if tags.count() > 1:
-            raise forms.ValidationError(_('Select at most one team.'))
-        return tags
+    def clean(self):
+        cleaned = super().clean()
+        if cleaned.get('mode') == Collection.Mode.TAGS and not cleaned.get('filter_tags'):
+            self.add_error('filter_tags', _('Select at least one tag for a tag collection.'))
+        return cleaned
 
     class Meta:
         model = Collection
-        fields = ['title', 'description', 'visibility', 'tags']
+        fields = ['title', 'description', 'visibility', 'mode', 'team', 'filter_tags']
         labels = {
             'title': _('Title'),
             'description': _('Description'),
             'visibility': _('Visibility'),
-            'tags': _('Team'),
+            'mode': _('Collection type'),
+            'filter_tags': _('Content tags'),
         }
         widgets = {
             'title': forms.TextInput(attrs={'class': 'form-control'}),
             'description': forms.Textarea(attrs={'class': 'form-control', 'rows': 4}),
             'visibility': forms.Select(attrs={'class': 'form-select'}),
-            'tags': forms.CheckboxSelectMultiple(),
+            'mode': forms.Select(attrs={'class': 'form-select', 'x-model': 'mode'}),
+            'filter_tags': forms.CheckboxSelectMultiple(),
         }
 
 

core/migrations/0018_remove_collection_tags_collection_filter_tags_and_more.py

@@ -0,0 +1,27 @@
+# Generated by Django 5.2.17 on 2026-08-27 14:47
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('core', '0017_collection_collectionsection'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='collection',
+            name='tags',
+        ),
+        migrations.AddField(
+            model_name='collection',
+            name='filter_tags',
+            field=models.ManyToManyField(blank=True, related_name='tag_collections', to='core.tag'),
+        ),
+        migrations.AddField(
+            model_name='collection',
+            name='mode',
+            field=models.CharField(choices=[('manual', 'Manual collection'), ('tags', 'Tag collection')], default='manual', max_length=10),
+        ),
+    ]

core/models.py

@@ -35,7 +35,7 @@ def without_markdown_code(text):
 def delete_unused_tags(tags=None):
     """Delete tags that are no longer used by items or tag-based features."""
     candidates = Tag.objects.all() if tags is None else Tag.objects.filter(pk__in=[tag.pk for tag in tags])
-    candidates.filter(items__isnull=True, kanbans__isnull=True, api_keys__isnull=True, collections__isnull=True).exclude(
+    candidates.filter(items__isnull=True, kanbans__isnull=True, api_keys__isnull=True, tag_collections__isnull=True).exclude(
         name__in=Team.objects.values_list('slug', flat=True),
     ).delete()
 
@@ -196,12 +196,17 @@ class Kanban(models.Model):
 
 
 class Collection(models.Model):
+    class Mode(models.TextChoices):
+        MANUAL = 'manual', _('Manual collection')
+        TAGS = 'tags', _('Tag collection')
+
     owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name='collections')
     team = models.ForeignKey(Team, on_delete=models.SET_NULL, blank=True, null=True, related_name='collections')
     title = models.CharField(max_length=200)
     description = models.TextField(blank=True)
     visibility = models.CharField(max_length=10, choices=Item.Visibility.choices, default=Item.Visibility.PRIVATE)
-    tags = models.ManyToManyField(Tag, blank=True, related_name='collections')
+    mode = models.CharField(max_length=10, choices=Mode.choices, default=Mode.MANUAL)
+    filter_tags = models.ManyToManyField(Tag, blank=True, related_name='tag_collections')
     created_at = models.DateTimeField(auto_now_add=True)
     updated_at = models.DateTimeField(auto_now=True)
 

core/templates/core/collection_detail.html

@@ -9,30 +9,29 @@
         <a class="btn btn-sm btn-outline-secondary mb-3" href="{% if user.is_authenticated %}{% url 'collection_list' %}{% else %}/{% endif %}">← {% if user.is_authenticated %}{% trans "Collections" %}{% else %}Start{% endif %}</a>
         <h1 class="display-5 mb-3">{{ collection.title }}</h1>
         <div class="d-flex flex-wrap gap-2 align-items-center">
+          {% if collection.mode == 'tags' %}<span class="badge text-bg-info">{% trans "Tag collection" %}</span>{% endif %}
           {% if collection.team %}<span class="badge text-bg-warning">{{ collection.team.name }}</span>{% else %}<span class="badge text-bg-light">{{ collection.get_visibility_display }}</span>{% endif %}
-          {% for tag in collection.tags.all %}<span class="badge rounded-pill text-bg-light">#{{ tag.name }}</span>{% endfor %}
+          {% for tag in collection.filter_tags.all %}<span class="badge rounded-pill text-bg-light">#{{ tag.name }}</span>{% endfor %}
         </div>
       </div>
-      {% if can_edit %}<a class="btn btn-dark" href="{% url 'collection_manage' collection.id %}">{% trans "Edit collection" %}</a>{% endif %}
+      {% if can_edit %}<a class="btn btn-dark" href="{% if collection.mode == 'tags' %}{% url 'collection_edit' collection.id %}{% else %}{% url 'collection_manage' collection.id %}{% endif %}">{% trans "Edit collection" %}</a>{% endif %}
     </div>
     {% if collection.description %}<div class="content lead mt-4">{{ collection.description|markdown }}</div>{% endif %}
   </header>
 
-  {% if sections %}
+  {% if sections or tag_items %}
     <nav class="collection-toc mb-5" aria-label="{% trans 'Contents' %}">
       <div class="small fw-semibold text-uppercase text-muted mb-2">{% trans "Contents" %}</div>
-      <ol class="mb-0">{% for section in sections %}<li><a href="#section-{{ section.id }}">{{ section.title|default:section.item.content|truncatechars:90 }}</a></li>{% endfor %}</ol>
+      <ol class="mb-0">{% if collection.mode == 'tags' %}{% for item in tag_items %}<li><a href="#item-{{ item.id }}">{{ item.content|truncatechars:90 }}</a></li>{% endfor %}{% else %}{% for section in sections %}<li><a href="#section-{{ section.id }}">{{ section.title|default:section.item.content|truncatechars:90 }}</a></li>{% endfor %}{% endif %}</ol>
     </nav>
   {% endif %}
 
   <div class="collection-flow content">
-    {% for section in sections %}
-      <section id="section-{{ section.id }}" class="collection-flow-section">
-        {% if section.title %}<h2>{{ section.title }}</h2>{% endif %}
-        {{ section.item|item_markdown }}
-        {% if section.item.comment %}<div class="text-muted border-start ps-3 mt-3">{{ section.item.comment|markdown }}</div>{% endif %}
-      </section>
-    {% empty %}<div class="text-center text-muted py-5">{% trans "This collection has no sections yet." %}</div>{% endfor %}
+    {% if collection.mode == 'tags' %}
+      {% for item in tag_items %}<section id="item-{{ item.id }}" class="collection-flow-section">{{ item|item_markdown }}{% if item.comment %}<div class="text-muted border-start ps-3 mt-3">{{ item.comment|markdown }}</div>{% endif %}</section>{% empty %}<div class="text-center text-muted py-5">{% trans "No notes match the selected tags yet." %}</div>{% endfor %}
+    {% else %}
+      {% for section in sections %}<section id="section-{{ section.id }}" class="collection-flow-section">{% if section.title %}<h2>{{ section.title }}</h2>{% endif %}{{ section.item|item_markdown }}{% if section.item.comment %}<div class="text-muted border-start ps-3 mt-3">{{ section.item.comment|markdown }}</div>{% endif %}</section>{% empty %}<div class="text-center text-muted py-5">{% trans "This collection has no sections yet." %}</div>{% endfor %}
+    {% endif %}
   </div>
 </article>
 {% endblock %}

core/templates/core/collection_form.html

@@ -4,14 +4,16 @@
 <div class="d-md-none alert alert-info">{% trans "Collections are currently available on desktop only." %}</div>
 <div class="d-none d-md-block">
   <a class="btn btn-sm btn-outline-secondary mb-3" href="{% if collection %}{{ collection.get_absolute_url }}{% else %}{% url 'collection_list' %}{% endif %}">← {% trans "back" %}</a>
-  <form method="post" class="card item-card"><div class="card-body vstack gap-3">
+  <form method="post" class="card item-card" x-data="{mode:'{{ form.mode.value|default:'manual'|escapejs }}'}"><div class="card-body vstack gap-3">
     <h1 class="h3 mb-0">{{ heading }}</h1>
     {% csrf_token %}
     {% if form.non_field_errors %}<div class="alert alert-danger mb-0">{{ form.non_field_errors }}</div>{% endif %}
     <div><label class="form-label">{{ form.title.label }}</label>{{ form.title }}{{ form.title.errors }}</div>
     <div><label class="form-label">{{ form.description.label }}</label>{{ form.description }}{{ form.description.errors }}</div>
-    <div><label class="form-label">{{ form.visibility.label }}</label>{{ form.visibility }}{{ form.visibility.errors }}<div class="form-text">{% trans "Optional. Selecting a team makes the collection visible and editable for that team." %}</div></div>
-    <div><label class="form-label">{{ form.tags.label }}</label><div class="border rounded p-3 collection-tags">{% if form.tags.field.queryset.exists %}{{ form.tags }}{% else %}<span class="text-muted small">{% trans "You do not belong to a team." %}</span>{% endif %}</div>{{ form.tags.errors }}</div>
+    <div><label class="form-label">{{ form.mode.label }}</label>{{ form.mode }}{{ form.mode.errors }}<div class="form-text">{% trans "Tag collections update automatically and are sorted by note creation time." %}</div></div>
+    <div><label class="form-label">{{ form.visibility.label }}</label>{{ form.visibility }}{{ form.visibility.errors }}</div>
+    <div><label class="form-label">{{ form.team.label }}</label>{{ form.team }}{{ form.team.errors }}<div class="form-text">{% trans "Optional. Selecting a team makes the collection visible and editable for that team." %}</div></div>
+    <div x-show="mode === 'tags'"><label class="form-label">{{ form.filter_tags.label }}</label><div class="border rounded p-3 collection-tags">{% if form.filter_tags.field.queryset.exists %}{{ form.filter_tags }}{% else %}<span class="text-muted small">{% trans "No content tags are available yet." %}</span>{% endif %}</div>{{ form.filter_tags.errors }}<div class="form-text">{% trans "Notes must contain all selected tags. Team tags are not content filters." %}</div></div>
     <div class="d-flex gap-2"><button class="btn btn-dark">{% trans "Save" %}</button><a class="btn btn-outline-secondary" href="{% if collection %}{{ collection.get_absolute_url }}{% else %}{% url 'collection_list' %}{% endif %}">{% trans "Cancel" %}</a></div>
   </div></form>
 </div>

core/templates/core/collection_list.html

@@ -8,13 +8,14 @@
     <a class="btn btn-dark" href="{% url 'collection_create' %}">{% trans "New collection" %}</a>
   </div>
   <div class="row g-3">
-    {% for collection in collections %}
+    {% for entry in entries %}{% with collection=entry.collection %}
       <div class="col-md-6"><a class="card item-card h-100 text-decoration-none text-dark" href="{{ collection.get_absolute_url }}"><div class="card-body">
-        <div class="d-flex justify-content-between gap-2"><h2 class="h5 mb-1">{{ collection.title }}</h2>{% if collection.team %}<span class="badge text-bg-warning">{{ collection.team.name }}</span>{% else %}<span class="badge text-bg-light">{{ collection.get_visibility_display }}</span>{% endif %}</div>
+        <div class="d-flex justify-content-between gap-2"><h2 class="h5 mb-1">{{ collection.title }}</h2><div class="d-flex gap-1">{% if collection.mode == 'tags' %}<span class="badge text-bg-info">{% trans "Tag collection" %}</span>{% endif %}{% if collection.team %}<span class="badge text-bg-warning">{{ collection.team.name }}</span>{% else %}<span class="badge text-bg-light">{{ collection.get_visibility_display }}</span>{% endif %}</div></div>
         {% if collection.description %}<p class="text-muted mt-2 mb-2">{{ collection.description|truncatechars:140 }}</p>{% endif %}
-        <div class="small text-muted">{{ collection.sections.count }} {% trans "sections" %} · {{ collection.updated_at|date:'d.m.Y H:i' }}</div>
+        {% if collection.mode == 'tags' %}<div class="mb-2">{% for tag in collection.filter_tags.all %}<span class="badge rounded-pill text-bg-light">#{{ tag.name }}</span> {% endfor %}</div>{% endif %}
+        <div class="small text-muted">{{ entry.section_count }} {% trans "sections" %} · {{ collection.updated_at|date:'d.m.Y H:i' }}</div>
       </div></a></div>
-    {% empty %}<div class="col-12 text-center text-muted py-5">{% trans "No collections yet." %}</div>{% endfor %}
+    {% endwith %}{% empty %}<div class="col-12 text-center text-muted py-5">{% trans "No collections yet." %}</div>{% endfor %}
   </div>
 </div>
 {% endblock %}

core/templates/core/collection_manage.html

@@ -9,7 +9,7 @@
       <h1 class="display-6 mb-2">{{ collection.title }}</h1>
       <div class="d-flex flex-wrap gap-2 align-items-center">
         {% if collection.team %}<span class="badge text-bg-warning">{{ collection.team.name }}</span>{% else %}<span class="badge text-bg-light">{{ collection.get_visibility_display }}</span>{% endif %}
-        {% for tag in collection.tags.all %}<span class="badge rounded-pill text-bg-light">#{{ tag.name }}</span>{% endfor %}
+        {% for tag in collection.filter_tags.all %}<span class="badge rounded-pill text-bg-light">#{{ tag.name }}</span>{% endfor %}
       </div>
     </div>
     {% if can_edit %}<div class="d-flex gap-2"><a class="btn btn-outline-secondary" href="{% url 'collection_edit' collection.id %}">{% trans "Collection settings" %}</a>{% if can_delete %}<form method="post" action="{% url 'collection_delete' collection.id %}" onsubmit="return confirm('{% trans "Delete collection? The notes remain available." %}')">{% csrf_token %}<button class="btn btn-outline-danger">{% trans "Delete" %}</button></form>{% endif %}</div>{% endif %}

core/tests.py

@@ -154,7 +154,7 @@ class CollectionTests(TestCase):
 
     def test_create_collection_and_add_compatible_note(self):
         response = self.client.post(reverse('collection_create'), {
-            'title': 'Documentation', 'description': 'Guide', 'visibility': Item.Visibility.PRIVATE,
+            'title': 'Documentation', 'description': 'Guide', 'visibility': Item.Visibility.PRIVATE, 'mode': Collection.Mode.MANUAL,
         })
         collection = Collection.objects.get()
         self.assertRedirects(response, collection.get_absolute_url())
@@ -199,12 +199,12 @@ class CollectionTests(TestCase):
         self.assertEqual(response.status_code, 409)
         self.assertTrue(Item.objects.filter(pk=note.id).exists())
 
-    def test_team_tag_creates_team_collection(self):
+    def test_team_selection_creates_team_collection(self):
         team = Team.objects.create(name='Docs team', slug='docs', owner=self.user)
         TeamMembership.objects.create(team=team, user=self.user, role=TeamMembership.Role.OWNER)
-        tag = Tag.objects.create(name='docs')
         response = self.client.post(reverse('collection_create'), {
-            'title': 'Team guide', 'visibility': Item.Visibility.PRIVATE, 'tags': [tag.id],
+            'title': 'Team guide', 'visibility': Item.Visibility.PRIVATE,
+            'mode': Collection.Mode.MANUAL, 'team': team.id,
         })
         collection = Collection.objects.get()
         self.assertRedirects(response, collection.get_absolute_url())
@@ -218,13 +218,36 @@ class CollectionTests(TestCase):
         response = self.client.get(reverse('collection_manage', args=[collection.id]))
         self.assertNotContains(response, f'name="item_id" value="{public_note.id}"')
 
-    def test_collection_form_only_offers_team_tags(self):
+    def test_collection_form_separates_teams_and_content_tags(self):
         team = Team.objects.create(name='Docs team', slug='docs', owner=self.user)
         TeamMembership.objects.create(team=team, user=self.user, role=TeamMembership.Role.OWNER)
         Tag.objects.create(name='docs')
-        Tag.objects.create(name='ordinary')
+        note = Item.objects.create(owner=self.user, content='#ordinary')
+        note.sync_metadata()
         response = self.client.get(reverse('collection_create'))
-        self.assertEqual(list(response.context['form'].fields['tags'].queryset.values_list('name', flat=True)), ['docs'])
+        form = response.context['form']
+        self.assertEqual(list(form.fields['team'].queryset), [team])
+        self.assertEqual(list(form.fields['filter_tags'].queryset.values_list('name', flat=True)), ['ordinary'])
+
+    def test_tag_collection_is_dynamic_and_sorted_by_creation(self):
+        first = Item.objects.create(owner=self.user, kind=Item.Kind.NOTE, content='First #guide #basics')
+        first.sync_metadata()
+        Item.objects.create(owner=self.user, kind=Item.Kind.NOTE, content='Ignored #guide').sync_metadata()
+        second = Item.objects.create(owner=self.user, kind=Item.Kind.NOTE, content='Second #guide #basics')
+        second.sync_metadata()
+        collection = Collection.objects.create(owner=self.user, title='Automatic', mode=Collection.Mode.TAGS)
+        collection.filter_tags.set(Tag.objects.filter(name__in=['guide', 'basics']))
+
+        response = self.client.get(collection.get_absolute_url())
+        html = response.content.decode()
+        self.assertContains(response, 'Tag-Sammlung')
+        self.assertLess(html.index('First #guide'), html.index('Second #guide'))
+        self.assertNotContains(response, 'Ignored #guide')
+        self.assertContains(response, reverse('collection_edit', args=[collection.id]))
+        self.assertNotContains(response, reverse('collection_manage', args=[collection.id]))
+
+        manage_response = self.client.get(reverse('collection_manage', args=[collection.id]))
+        self.assertRedirects(manage_response, reverse('collection_edit', args=[collection.id]))
 
     def test_collection_opens_as_continuous_reading_view(self):
         collection = Collection.objects.create(owner=self.user, title='Reading view')
@@ -247,8 +270,8 @@ class CollectionTests(TestCase):
 
     def test_collection_tag_is_not_removed_as_unused(self):
         tag = Tag.objects.create(name='documentation')
-        collection = Collection.objects.create(owner=self.user, title='Tagged')
-        collection.tags.add(tag)
+        collection = Collection.objects.create(owner=self.user, title='Tagged', mode=Collection.Mode.TAGS)
+        collection.filter_tags.add(tag)
         note = Item.objects.create(owner=self.user, content='#temporary')
         note.sync_metadata()
         note.content = ''

core/views.py

@@ -536,7 +536,7 @@ def team_accept_invite(request, token):
 
 
 def visible_collections(user):
-    qs = Collection.objects.select_related('owner', 'team').prefetch_related('tags', 'sections__item')
+    qs = Collection.objects.select_related('owner', 'team').prefetch_related('filter_tags', 'sections__item')
     if user.is_authenticated:
         return qs.filter(Q(owner=user) | Q(team_id__in=user_team_ids(user)) | Q(visibility=Item.Visibility.PUBLIC)).distinct()
     return qs.filter(visibility=Item.Visibility.PUBLIC)
@@ -569,14 +569,25 @@ def collection_item_is_compatible(collection, item):
 
 
 def collection_target_from_form(form, user):
-    tags = form.cleaned_data.get('tags')
-    tag_names = list(tags.values_list('name', flat=True)) if tags is not None else []
-    membership = TeamMembership.objects.select_related('team').filter(user=user, team__slug__in=tag_names).first()
-    if membership:
-        return Item.Visibility.TEAM, membership.team
+    team = form.cleaned_data.get('team')
+    if team:
+        return Item.Visibility.TEAM, team
     return form.cleaned_data['visibility'], None
 
 
+def collection_tag_items(collection):
+    items = Item.objects.filter(kind=Item.Kind.NOTE).select_related('owner', 'team').prefetch_related('tags', 'attachments')
+    if collection.visibility == Item.Visibility.PUBLIC:
+        items = items.filter(visibility=Item.Visibility.PUBLIC)
+    elif collection.visibility == Item.Visibility.TEAM:
+        items = items.filter(Q(visibility=Item.Visibility.PUBLIC) | Q(visibility=Item.Visibility.TEAM, team=collection.team))
+    else:
+        items = items.filter(Q(visibility=Item.Visibility.PUBLIC) | Q(visibility=Item.Visibility.PRIVATE, owner=collection.owner))
+    for tag in collection.filter_tags.all():
+        items = items.filter(tags=tag)
+    return items.distinct().order_by('created_at', 'id')
+
+
 def item_can_change_for_collection(user, item, collection):
     if not user_can_edit_item(user, item):
         return False
@@ -659,8 +670,11 @@ def collection_detail_context(request, collection, pending_item=None):
 
 @login_required
 def collection_list(request):
-    collections = visible_collections(request.user)
-    return render(request, 'core/collection_list.html', {'collections': collections})
+    entries = []
+    for collection in visible_collections(request.user).prefetch_related('filter_tags'):
+        count = collection_tag_items(collection).count() if collection.mode == Collection.Mode.TAGS else collection.sections.count()
+        entries.append({'collection': collection, 'section_count': count})
+    return render(request, 'core/collection_list.html', {'entries': entries})
 
 
 @login_required
@@ -670,7 +684,7 @@ def collection_create(request):
         if form.is_valid():
             visibility, team = collection_target_from_form(form, request.user)
             if visibility == Item.Visibility.TEAM and not team:
-                form.add_error('visibility', _('Select a team tag for a team collection.'))
+                form.add_error('team', _('Select a team for a team collection.'))
             else:
                 collection = form.save(commit=False)
                 collection.owner = request.user
@@ -678,6 +692,8 @@ def collection_create(request):
                 collection.team = team
                 collection.save()
                 form.save_m2m()
+                if collection.mode == Collection.Mode.MANUAL:
+                    collection.filter_tags.clear()
                 messages.success(request, _('Collection created.'))
                 return redirect(collection)
     else:
@@ -694,20 +710,26 @@ def collection_edit(request, pk):
         form = CollectionForm(request.POST, instance=collection, user=request.user)
         if form.is_valid():
             visibility, team = collection_target_from_form(form, request.user)
-            incompatible = any(not collection_scope_allows_item(
+            target_mode = form.cleaned_data['mode']
+            has_manual_sections = collection.mode == Collection.Mode.MANUAL and collection.sections.exists()
+            incompatible = target_mode == Collection.Mode.MANUAL and any(not collection_scope_allows_item(
                 visibility, team.id if team else None, collection.owner_id,
                 section.item.visibility, section.item.team_id, section.item.owner_id,
             ) for section in collection.sections.select_related('item'))
-            if incompatible:
+            if target_mode == Collection.Mode.TAGS and has_manual_sections:
+                form.add_error('mode', _('Remove all manual sections before changing to a tag collection.'))
+            elif incompatible:
                 form.add_error(None, _('The collection visibility cannot change while it contains incompatible notes.'))
             elif visibility == Item.Visibility.TEAM and not team:
-                form.add_error('visibility', _('Select a team tag for a team collection.'))
+                form.add_error('team', _('Select a team for a team collection.'))
             else:
                 collection = form.save(commit=False)
                 collection.visibility = visibility
                 collection.team = team
                 collection.save()
                 form.save_m2m()
+                if collection.mode == Collection.Mode.MANUAL:
+                    collection.filter_tags.clear()
                 messages.success(request, _('Collection saved.'))
                 return redirect(collection)
     else:
@@ -719,7 +741,8 @@ def collection_detail(request, pk):
     collection = get_object_or_404(visible_collections(request.user), pk=pk)
     return render(request, 'core/collection_detail.html', {
         'collection': collection,
-        'sections': collection.sections.select_related('item').prefetch_related('item__tags', 'item__attachments'),
+        'sections': collection.sections.select_related('item').prefetch_related('item__tags', 'item__attachments') if collection.mode == Collection.Mode.MANUAL else [],
+        'tag_items': collection_tag_items(collection) if collection.mode == Collection.Mode.TAGS else [],
         'can_edit': user_can_edit_collection(request.user, collection),
     })
 
@@ -729,6 +752,8 @@ def collection_manage(request, pk):
     collection = get_object_or_404(visible_collections(request.user), pk=pk)
     if not user_can_edit_collection(request.user, collection):
         return JsonResponse({'error': 'forbidden'}, status=403)
+    if collection.mode == Collection.Mode.TAGS:
+        return redirect('collection_edit', pk=collection.pk)
     manage_url = reverse('collection_manage', args=[collection.pk])
     if request.method == 'POST':
         action = request.POST.get('action')