feat(backlog): Epic-Hierarchie mit parent_backlog_id (ADP P2)

Epics als Backlog-Container mit Baum-UI, Convert-Guard und pytest-Abdeckung — Roll-up bleibt für P4 offen.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/migrations/028_backlog_epic_hierarchy.sql

@@ -0,0 +1,14 @@
+-- AP2.2f / ADP Backlog Epic-Hierarchie — parent_backlog_id + item_kind epic
+
+ALTER TABLE backlog_items
+    ADD COLUMN IF NOT EXISTS parent_backlog_id UUID NULL
+        REFERENCES backlog_items (id) ON DELETE SET NULL;
+
+CREATE INDEX IF NOT EXISTS idx_backlog_parent_backlog
+    ON backlog_items (tenant_id, initiative_id, parent_backlog_id)
+    WHERE parent_backlog_id IS NOT NULL;
+
+ALTER TABLE backlog_items DROP CONSTRAINT IF EXISTS backlog_items_item_kind_check;
+ALTER TABLE backlog_items
+    ADD CONSTRAINT backlog_items_item_kind_check
+        CHECK (item_kind IN ('story', 'bug', 'issue', 'epic'));

backend/routers/backlog.py

@@ -20,8 +20,9 @@ class BacklogCreateRequest(BaseModel):
     priority: Literal["low", "normal", "high"] = "normal"
     roadmap_item_id: Optional[str] = None
     sort_order: Optional[int] = None
-    item_kind: Literal["story", "bug", "issue"] = "story"
+    item_kind: Literal["story", "bug", "issue", "epic"] = "story"
     parent_action_id: Optional[str] = None
+    parent_backlog_id: Optional[str] = None
 
 
 class BacklogUpdateRequest(BaseModel):
@@ -32,9 +33,11 @@ class BacklogUpdateRequest(BaseModel):
     roadmap_item_id: Optional[str] = None
     clear_roadmap_item: bool = False
     sort_order: Optional[int] = None
-    item_kind: Optional[Literal["story", "bug", "issue"]] = None
+    item_kind: Optional[Literal["story", "bug", "issue", "epic"]] = None
     parent_action_id: Optional[str] = None
     clear_parent_action: bool = False
+    parent_backlog_id: Optional[str] = None
+    clear_parent_backlog: bool = False
 
 
 class BacklogConvertRequest(BaseModel):
@@ -77,6 +80,8 @@ def update_backlog_item(
             item_kind=body.item_kind,
             parent_action_id=body.parent_action_id,
             clear_parent_action=body.clear_parent_action,
+            parent_backlog_id=body.parent_backlog_id,
+            clear_parent_backlog=body.clear_parent_backlog,
         )
     except ValueError as exc:
         raise HTTPException(status_code=400, detail=str(exc)) from exc
@@ -90,11 +95,15 @@ def delete_backlog_item(
     backlog_item_id: str,
     ctx: TenantContext = Depends(require_capability("kairo.backlog.manage")),
 ):
-    if not backlog_service.delete_backlog_item(
-        tenant_id=ctx.tenant_id,
-        backlog_item_id=backlog_item_id,
-        user_id=ctx.user_id,
-    ):
+    try:
+        deleted = backlog_service.delete_backlog_item(
+            tenant_id=ctx.tenant_id,
+            backlog_item_id=backlog_item_id,
+            user_id=ctx.user_id,
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=400, detail=str(exc)) from exc
+    if not deleted:
         raise HTTPException(status_code=404, detail="Backlog-Item nicht gefunden")
 
 

backend/routers/initiatives.py

@@ -89,8 +89,9 @@ class BacklogCreateRequest(BaseModel):
     status: Literal["new", "triaged", "accepted", "rejected"] = "new"
     priority: Literal["low", "normal", "high"] = "normal"
     roadmap_item_id: Optional[str] = None
-    item_kind: Literal["story", "bug", "issue"] = "story"
+    item_kind: Literal["story", "bug", "issue", "epic"] = "story"
     parent_action_id: Optional[str] = None
+    parent_backlog_id: Optional[str] = None
 
 
 class MilestoneCreateRequest(BaseModel):
@@ -438,6 +439,7 @@ def create_initiative_backlog_item(
             roadmap_item_id=body.roadmap_item_id,
             item_kind=body.item_kind,
             parent_action_id=body.parent_action_id,
+            parent_backlog_id=body.parent_backlog_id,
             user_id=ctx.user_id,
         )
     except ValueError as exc:

backend/services/backlog.py

@@ -13,15 +13,16 @@ from services.initiatives import PRIORITIES, get_initiative
 from services.plan_ist import validate_roadmap_item_in_initiative
 
 BacklogStatus = Literal["new", "triaged", "accepted", "rejected", "converted"]
-BacklogItemKind = Literal["story", "bug", "issue"]
+BacklogItemKind = Literal["story", "bug", "issue", "epic"]
 
 BACKLOG_STATUSES = frozenset({"new", "triaged", "accepted", "rejected", "converted"})
-BACKLOG_ITEM_KINDS = frozenset({"story", "bug", "issue"})
+BACKLOG_ITEM_KINDS = frozenset({"story", "bug", "issue", "epic"})
+CONVERTIBLE_ITEM_KINDS = frozenset({"story", "bug", "issue"})
 
 _BACKLOG_COLUMNS = """
     id, tenant_id, initiative_id, title, description, status,
     priority, roadmap_item_id, converted_action_id, sort_order, item_kind,
-    parent_action_id, created_at, updated_at
+    parent_action_id, parent_backlog_id, created_at, updated_at
 """
 
 
@@ -34,6 +35,7 @@ def _serialize_row(row: dict[str, Any]) -> dict[str, Any]:
         "converted_action_id",
         "roadmap_item_id",
         "parent_action_id",
+        "parent_backlog_id",
     ):
         if result.get(key):
             result[key] = str(result[key])
@@ -92,6 +94,48 @@ def _validate_parent_action_in_initiative(
         raise ValueError("Referenz muss ein Feature-Arbeitspaket sein, kein Bug/Issue")
 
 
+def _validate_backlog_hierarchy(
+    *,
+    cur,
+    tenant_id: str,
+    initiative_id: str,
+    item_kind: str,
+    parent_backlog_id: Optional[str],
+    parent_action_id: Optional[str],
+    backlog_item_id: Optional[str] = None,
+) -> None:
+    if item_kind == "epic":
+        if parent_backlog_id:
+            raise ValueError("Epic kann keinem übergeordneten Backlog-Item zugeordnet werden")
+        if parent_action_id:
+            raise ValueError("Epic kann keinem Arbeitspaket zugeordnet werden")
+        return
+
+    if not parent_backlog_id:
+        return
+
+    if backlog_item_id and parent_backlog_id == backlog_item_id:
+        raise ValueError("Item kann nicht sich selbst als Epic referenzieren")
+
+    cur.execute(
+        """
+        SELECT id, item_kind, initiative_id
+        FROM backlog_items
+        WHERE id = %s AND tenant_id = %s
+        """,
+        (parent_backlog_id, tenant_id),
+    )
+    parent = cur.fetchone()
+    if not parent:
+        raise ValueError("Epic-Referenz nicht gefunden")
+    parent_initiative = parent["initiative_id"] if isinstance(parent, dict) else parent[2]
+    parent_kind = parent["item_kind"] if isinstance(parent, dict) else parent[1]
+    if str(parent_initiative) != initiative_id:
+        raise ValueError("Epic gehört zu einem anderen Vorhaben")
+    if parent_kind != "epic":
+        raise ValueError("Übergeordnetes Item muss ein Epic sein")
+
+
 def create_backlog_item(
     *,
     tenant_id: str,
@@ -104,6 +148,7 @@ def create_backlog_item(
     sort_order: Optional[int] = None,
     item_kind: BacklogItemKind = "story",
     parent_action_id: Optional[str] = None,
+    parent_backlog_id: Optional[str] = None,
     user_id: Optional[str] = None,
 ) -> dict[str, Any]:
     title = title.strip()
@@ -130,6 +175,14 @@ def create_backlog_item(
                 initiative_id=initiative_id,
                 parent_action_id=parent_action_id,
             )
+            _validate_backlog_hierarchy(
+                cur=cur,
+                tenant_id=tenant_id,
+                initiative_id=initiative_id,
+                item_kind=item_kind,
+                parent_backlog_id=parent_backlog_id,
+                parent_action_id=parent_action_id,
+            )
             cur.execute(
                 """
                 SELECT COALESCE(MAX(sort_order), -10) + 10 AS next_order
@@ -143,9 +196,9 @@ def create_backlog_item(
                 f"""
                 INSERT INTO backlog_items (
                     tenant_id, initiative_id, title, description, status, priority,
-                    roadmap_item_id, sort_order, item_kind, parent_action_id
+                    roadmap_item_id, sort_order, item_kind, parent_action_id, parent_backlog_id
                 )
-                VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
+                VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
                 RETURNING {_BACKLOG_COLUMNS}
                 """,
                 (
@@ -159,6 +212,7 @@ def create_backlog_item(
                     sort_order if sort_order is not None else next_order,
                     item_kind,
                     parent_action_id,
+                    parent_backlog_id,
                 ),
             )
             row = _serialize_row(dict(cur.fetchone()))
@@ -229,6 +283,8 @@ def update_backlog_item(
     item_kind: Optional[BacklogItemKind] = None,
     parent_action_id: Optional[str] = None,
     clear_parent_action: bool = False,
+    parent_backlog_id: Optional[str] = None,
+    clear_parent_backlog: bool = False,
 ) -> Optional[dict[str, Any]]:
     existing = get_backlog_item(tenant_id=tenant_id, backlog_item_id=backlog_item_id)
     if not existing:
@@ -285,16 +341,46 @@ def update_backlog_item(
     elif parent_action_id is not None:
         updates.append("parent_action_id = %s")
         params.append(parent_action_id)
+    if clear_parent_backlog:
+        updates.append("parent_backlog_id = NULL")
+    elif parent_backlog_id is not None:
+        updates.append("parent_backlog_id = %s")
+        params.append(parent_backlog_id)
 
     if not updates:
         return existing
 
+    effective_kind = item_kind if item_kind is not None else existing.get("item_kind") or "story"
+    effective_parent_backlog = (
+        None
+        if clear_parent_backlog
+        else parent_backlog_id
+        if parent_backlog_id is not None
+        else existing.get("parent_backlog_id")
+    )
+    effective_parent_action = (
+        None
+        if clear_parent_action
+        else parent_action_id
+        if parent_action_id is not None
+        else existing.get("parent_action_id")
+    )
+
     updates.append("updated_at = NOW()")
     params.extend([backlog_item_id, tenant_id])
 
     conn = get_connection()
     try:
         with conn.cursor(cursor_factory=RealDictCursor) as cur:
+            _validate_backlog_hierarchy(
+                cur=cur,
+                tenant_id=tenant_id,
+                initiative_id=existing["initiative_id"],
+                item_kind=effective_kind,
+                parent_backlog_id=effective_parent_backlog,
+                parent_action_id=effective_parent_action,
+                backlog_item_id=backlog_item_id,
+            )
             if parent_action_id is not None and not clear_parent_action:
                 _validate_parent_action_in_initiative(
                     cur=cur,
@@ -348,6 +434,18 @@ def delete_backlog_item(
     conn = get_connection()
     try:
         with conn.cursor() as cur:
+            cur.execute(
+                """
+                SELECT id FROM backlog_items
+                WHERE parent_backlog_id = %s AND tenant_id = %s AND status != 'converted'
+                LIMIT 1
+                """,
+                (backlog_item_id, tenant_id),
+            )
+            if cur.fetchone():
+                raise ValueError(
+                    "Epic mit untergeordneten Items kann nicht gelöscht werden"
+                )
             cur.execute(
                 "DELETE FROM backlog_items WHERE id = %s AND tenant_id = %s RETURNING id",
                 (backlog_item_id, tenant_id),
@@ -384,6 +482,10 @@ def convert_backlog_to_action(
     if existing["status"] not in ("accepted", "triaged", "new"):
         raise ValueError("Backlog-Item kann in diesem Status nicht konvertiert werden")
 
+    item_kind = existing.get("item_kind") or "story"
+    if item_kind not in CONVERTIBLE_ITEM_KINDS:
+        raise ValueError("Epic kann nicht direkt in ein Arbeitspaket umgewandelt werden")
+
     resolved_cycle_id = work_cycle_id
     if not resolved_cycle_id and assign_active_sprint:
         from services.work_cycle import get_active_work_cycle
@@ -394,7 +496,6 @@ def convert_backlog_to_action(
         if active:
             resolved_cycle_id = active["id"]
 
-    item_kind = existing.get("item_kind") or "story"
     action = create_action(
         tenant_id=tenant_id,
         initiative_id=existing["initiative_id"],

backend/tests/test_ap22f_backlog_epic_hierarchy.py

@@ -0,0 +1,161 @@
+"""AP2.2f — Backlog Epic-Hierarchie (parent_backlog_id + item_kind epic)."""
+
+from __future__ import annotations
+
+from tests.factories import provision_user_in_tenant
+from tests.test_initiatives_actions import _auth, _create_initiative, _login
+
+
+def _create_product_initiative(client, token, title="Epic Product"):
+    created = _create_initiative(
+        client,
+        token,
+        title=title,
+        archetype_key="initiative.product",
+    )
+    assert created.status_code == 201
+    return created.json()["id"]
+
+
+def test_create_epic_and_story_under_epic(client):
+    user = provision_user_in_tenant(tenant_role="admin")
+    token = _login(client, user)
+    initiative_id = _create_product_initiative(client, token)
+
+    epic = client.post(
+        f"/api/initiatives/{initiative_id}/backlog",
+        json={"title": "Checkout Epic", "item_kind": "epic", "status": "accepted"},
+        headers=_auth(token),
+    )
+    assert epic.status_code == 201
+    epic_id = epic.json()["id"]
+    assert epic.json()["item_kind"] == "epic"
+    assert epic.json().get("parent_backlog_id") is None
+
+    story = client.post(
+        f"/api/initiatives/{initiative_id}/backlog",
+        json={
+            "title": "Login Story",
+            "item_kind": "story",
+            "parent_backlog_id": epic_id,
+            "status": "accepted",
+        },
+        headers=_auth(token),
+    )
+    assert story.status_code == 201
+    assert story.json()["parent_backlog_id"] == epic_id
+
+    listed = client.get(
+        f"/api/initiatives/{initiative_id}/backlog",
+        headers=_auth(token),
+    )
+    assert listed.status_code == 200
+    by_id = {item["id"]: item for item in listed.json()}
+    assert by_id[story.json()["id"]]["parent_backlog_id"] == epic_id
+
+
+def test_epic_cannot_convert_to_action(client):
+    user = provision_user_in_tenant(tenant_role="admin")
+    token = _login(client, user)
+    initiative_id = _create_product_initiative(client, token, title="Epic Convert Block")
+
+    epic = client.post(
+        f"/api/initiatives/{initiative_id}/backlog",
+        json={"title": "Big Epic", "item_kind": "epic", "status": "accepted"},
+        headers=_auth(token),
+    )
+    epic_id = epic.json()["id"]
+
+    converted = client.post(
+        f"/api/backlog/{epic_id}/convert-to-action",
+        json={},
+        headers=_auth(token),
+    )
+    assert converted.status_code == 400
+    assert "Epic" in converted.json()["detail"]
+
+
+def test_story_under_epic_converts_to_action(client):
+    user = provision_user_in_tenant(tenant_role="admin")
+    token = _login(client, user)
+    initiative_id = _create_product_initiative(client, token, title="Story Convert")
+
+    epic = client.post(
+        f"/api/initiatives/{initiative_id}/backlog",
+        json={"title": "Epic", "item_kind": "epic", "status": "accepted"},
+        headers=_auth(token),
+    )
+    epic_id = epic.json()["id"]
+
+    story = client.post(
+        f"/api/initiatives/{initiative_id}/backlog",
+        json={
+            "title": "Story",
+            "item_kind": "story",
+            "parent_backlog_id": epic_id,
+            "status": "accepted",
+        },
+        headers=_auth(token),
+    )
+    story_id = story.json()["id"]
+
+    converted = client.post(
+        f"/api/backlog/{story_id}/convert-to-action",
+        json={},
+        headers=_auth(token),
+    )
+    assert converted.status_code == 201
+    assert converted.json()["action"]["title"] == "Story"
+
+
+def test_cannot_delete_epic_with_children(client):
+    user = provision_user_in_tenant(tenant_role="admin")
+    token = _login(client, user)
+    initiative_id = _create_product_initiative(client, token, title="Epic Delete Guard")
+
+    epic = client.post(
+        f"/api/initiatives/{initiative_id}/backlog",
+        json={"title": "Epic", "item_kind": "epic", "status": "accepted"},
+        headers=_auth(token),
+    )
+    epic_id = epic.json()["id"]
+
+    client.post(
+        f"/api/initiatives/{initiative_id}/backlog",
+        json={
+            "title": "Child Story",
+            "item_kind": "story",
+            "parent_backlog_id": epic_id,
+            "status": "new",
+        },
+        headers=_auth(token),
+    )
+
+    deleted = client.delete(f"/api/backlog/{epic_id}", headers=_auth(token))
+    assert deleted.status_code == 400
+    assert "untergeordneten" in deleted.json()["detail"]
+
+
+def test_epic_cannot_have_parent_backlog(client):
+    user = provision_user_in_tenant(tenant_role="admin")
+    token = _login(client, user)
+    initiative_id = _create_product_initiative(client, token, title="Epic Parent Guard")
+
+    epic_a = client.post(
+        f"/api/initiatives/{initiative_id}/backlog",
+        json={"title": "Epic A", "item_kind": "epic", "status": "accepted"},
+        headers=_auth(token),
+    )
+    epic_a_id = epic_a.json()["id"]
+
+    epic_b = client.post(
+        f"/api/initiatives/{initiative_id}/backlog",
+        json={
+            "title": "Epic B",
+            "item_kind": "epic",
+            "parent_backlog_id": epic_a_id,
+            "status": "accepted",
+        },
+        headers=_auth(token),
+    )
+    assert epic_b.status_code == 400

docs/product/Kairo_Implementation_Truth_Table_v0.1.md

@@ -49,7 +49,7 @@ Verhindert, dass Zielbild-Dokumente als Ist-Stand gelesen werden.
 | `actions.sort_order` | ◐ | Migration 023 |
 | BacklogItem | ✓ | Gate-Zuordnung AP1.6, `sort_order` |
 | BacklogItem kinds (MVP) | ◐ | `story`/`bug`/`issue` AP2.2e — global, nicht profilgebunden |
-| Backlog Epic-Hierarchie | ✗ | ADP P2: `epic` + `parent_backlog_id` — dokumentiert 2026-07-26 |
+| Backlog Epic-Hierarchie | ◐ | AP2.2f: `epic` + `parent_backlog_id`, Baum-UI, Convert-Guard — Roll-up (P4) offen |
 | Dual Commit (Direct AP) | ◐ | ADP P1: Plan→Arbeit im Product-Outline (2026-07-26) |
 | Profil-Vokabular Backlog | ✗ | ADP P3: Continuous vs. Agile labels via Operating Context |
 | Blocker | ✓ | `action_id` optional |

frontend/src/components/BacklogItemForm.jsx

@@ -1,45 +1,59 @@
+import { useMemo } from 'react'
 import {
   BACKLOG_STATUSES,
   BACKLOG_STATUS_LABELS,
   BACKLOG_ITEM_KINDS,
+  BACKLOG_ITEM_KINDS_WITH_EPIC,
   BACKLOG_ITEM_KIND_LABELS,
   PRIORITIES,
   PRIORITY_LABELS,
 } from '../constants/status.js'
 import { GateSelect } from './GateSelect.jsx'
 import { FeatureParentSelect } from './FeatureParentSelect.jsx'
+import { EpicParentSelect } from './EpicParentSelect.jsx'
 
 export function BacklogItemForm({
   initial = {},
   roadmapItems = [],
   featureActions = [],
+  epicItems = [],
+  epicHierarchyEnabled = false,
   onSubmit,
   onCancel,
   busy = false,
   submitLabel = 'Speichern',
   allowStatus = true,
 }) {
+  const itemKinds = epicHierarchyEnabled ? BACKLOG_ITEM_KINDS_WITH_EPIC : BACKLOG_ITEM_KINDS
+  const initialKind = initial.item_kind || 'story'
+  const isEpic = initialKind === 'epic'
+
   async function handleSubmit(e) {
     e.preventDefault()
     const form = e.target
     const gateValue = form.roadmap_item_id?.value ?? ''
     const parentValue = form.parent_action_id?.value ?? ''
+    const epicValue = form.parent_backlog_id?.value ?? ''
+    const itemKind = form.item_kind?.value || 'story'
     await onSubmit({
       title: form.title.value.trim(),
       description: form.description.value,
       status: form.status?.value,
       priority: form.priority.value,
-      item_kind: form.item_kind?.value || 'story',
+      item_kind: itemKind,
       roadmap_item_id: gateValue || undefined,
       clear_roadmap_item: gateValue === '',
-      parent_action_id: parentValue || undefined,
-      clear_parent_action: parentValue === '',
+      parent_action_id: itemKind === 'epic' ? undefined : parentValue || undefined,
+      clear_parent_action: itemKind === 'epic' ? true : parentValue === '',
+      parent_backlog_id: itemKind === 'epic' ? undefined : epicValue || undefined,
+      clear_parent_backlog: itemKind === 'epic' ? true : epicValue === '',
     })
   }
 
   const statusLocked = initial.status === 'converted'
   const showFeatureRef =
-    (initial.item_kind || 'story') !== 'story' || featureActions.length > 0
+    !isEpic &&
+    ((initial.item_kind || 'story') !== 'story' || featureActions.length > 0)
 
   return (
     <form className="form workspace-form backlog-item-form" onSubmit={handleSubmit}>
@@ -67,10 +81,10 @@ export function BacklogItemForm({
           Typ
           <select
             name="item_kind"
-            defaultValue={initial.item_kind || 'story'}
+            defaultValue={initialKind}
             disabled={statusLocked}
           >
-            {BACKLOG_ITEM_KINDS.map((kind) => (
+            {itemKinds.map((kind) => (
               <option key={kind} value={kind}>
                 {BACKLOG_ITEM_KIND_LABELS[kind]}
               </option>
@@ -113,6 +127,13 @@ export function BacklogItemForm({
           disabled={statusLocked}
         />
       )}
+      {epicHierarchyEnabled && !isEpic && (
+        <EpicParentSelect
+          epicItems={epicItems}
+          defaultValue={initial.parent_backlog_id || ''}
+          disabled={statusLocked}
+        />
+      )}
       {showFeatureRef && (
         <FeatureParentSelect
           featureActions={featureActions}

frontend/src/components/BacklogSection.jsx

@@ -7,6 +7,7 @@ import { BacklogItemForm } from './BacklogItemForm.jsx'
 import { ReorderControls } from './ReorderControls.jsx'
 import { gateTitleById } from './GateSelect.jsx'
 import { computeDropPatches, computeMovePatches, sortByOrder } from '../utils/reorder.js'
+import { buildBacklogDisplayRows, listEpicBacklogItems } from '../utils/backlogTree.js'
 import { useMinWidth } from '../hooks/useMinWidth.js'
 import { BACKLOG_ITEM_KIND_LABELS } from '../constants/status.js'
 import { actionTitleById } from '../utils/actionReferences.js'
@@ -82,6 +83,18 @@ export function BacklogSection({
     [items],
   )
 
+  const epicItems = useMemo(() => listEpicBacklogItems(items), [items])
+  const displayRows = useMemo(() => buildBacklogDisplayRows(items), [items])
+  const epicTitleById = useMemo(() => {
+    const map = new Map()
+    for (const epic of epicItems) {
+      map.set(epic.id, epic.title)
+    }
+    return map
+  }, [epicItems])
+
+  const epicHierarchyEnabled = sprintPlanningEnabled
+
   function closeModal() {
     setModalMode(null)
   }
@@ -94,6 +107,7 @@ export function BacklogSection({
       roadmap_item_id: payload.roadmap_item_id,
       item_kind: payload.item_kind,
       parent_action_id: payload.parent_action_id,
+      parent_backlog_id: payload.parent_backlog_id,
       status: payload.status || 'new',
     })
     closeModal()
@@ -111,6 +125,8 @@ export function BacklogSection({
       item_kind: payload.item_kind,
       parent_action_id: payload.parent_action_id,
       clear_parent_action: payload.clear_parent_action,
+      parent_backlog_id: payload.parent_backlog_id,
+      clear_parent_backlog: payload.clear_parent_backlog,
     })
     if (ok !== false) closeModal()
   }
@@ -158,7 +174,9 @@ export function BacklogSection({
   const modalTitle =
     modalMode?.kind === 'create' ? 'Backlog-Item anlegen' : 'Backlog-Item bearbeiten'
 
-  const committableItems = sortedItems.filter((item) => COMMITTABLE_STATUSES.has(item.status))
+  const committableItems = sortedItems.filter(
+    (item) => COMMITTABLE_STATUSES.has(item.status) && item.item_kind !== 'epic',
+  )
   const selectedCommittable = committableItems.filter((item) => selectedIds.has(item.id))
 
   function toggleSelected(itemId) {
@@ -267,20 +285,24 @@ export function BacklogSection({
       {items.length === 0 && <EmptyState message="Backlog ist leer." />}
 
       <ul className="item-list backlog-reorder-list">
-        {sortedItems.map((item, index) => {
+        {displayRows.map(({ item, depth }) => {
           const isDragging = dragItemId === item.id
           const isDropTarget = dropTargetId === item.id && dragItemId && dragItemId !== item.id
           const reorderable = canReorder && item.status !== 'converted'
+          const isEpic = item.item_kind === 'epic'
+          const flatIndex = sortedItems.findIndex((row) => row.id === item.id)
 
           return (
             <li
               key={item.id}
               className={
                 'list-item card-list-item backlog-reorder-item' +
+                (depth > 0 ? ' backlog-reorder-item--child' : '') +
                 (isDragging ? ' backlog-reorder-item--dragging' : '') +
                 (isDropTarget ? ' backlog-reorder-item--drop-target' : '') +
                 (reorderable && isDesktop ? ' backlog-reorder-item--draggable' : '')
               }
+              style={depth > 0 ? { marginLeft: `${depth * 1.25}rem` } : undefined}
               draggable={reorderable && isDesktop}
               onDragStart={(event) => handleDragStart(event, item.id)}
               onDragEnd={handleDragEnd}
@@ -292,7 +314,7 @@ export function BacklogSection({
                   ⋮⋮
                 </span>
               )}
-              {showSprintPlanning && canManage && COMMITTABLE_STATUSES.has(item.status) && (
+              {showSprintPlanning && canManage && COMMITTABLE_STATUSES.has(item.status) && !isEpic && (
                 <label className="backlog-select-checkbox">
                   <input
                     type="checkbox"
@@ -318,6 +340,11 @@ export function BacklogSection({
                 {item.description && (
                   <p className="list-item-desc">{item.description}</p>
                 )}
+                {item.parent_backlog_id && (
+                  <p className="list-item-sub muted">
+                    Epic: {epicTitleById.get(item.parent_backlog_id) || '…'}
+                  </p>
+                )}
                 {item.parent_action_id && (
                   <p className="list-item-sub muted">
                     Feature: {actionTitleById(featureActions, item.parent_action_id) || '…'}
@@ -334,8 +361,8 @@ export function BacklogSection({
                 {reorderable && !isDesktop && (
                   <ReorderControls
                     itemId={item.id}
-                    canMoveUp={index > 0}
-                    canMoveDown={index < sortedItems.length - 1}
+                    canMoveUp={flatIndex > 0}
+                    canMoveDown={flatIndex < sortedItems.length - 1}
                     onMove={(direction) => handleMove(item.id, direction)}
                     busy={busy}
                   />
@@ -344,7 +371,7 @@ export function BacklogSection({
                 <PriorityBadge priority={item.priority} />
                 {canManage && item.status !== 'converted' && (
                   <>
-                    {COMMITTABLE_STATUSES.has(item.status) && (
+                    {COMMITTABLE_STATUSES.has(item.status) && !isEpic && (
                       <button
                         type="button"
                         className="btn btn-primary btn-sm"
@@ -393,6 +420,8 @@ export function BacklogSection({
           <BacklogItemForm
             roadmapItems={roadmapItems}
             featureActions={featureActions}
+            epicItems={epicItems}
+            epicHierarchyEnabled={epicHierarchyEnabled}
             onSubmit={handleCreateSubmit}
             onCancel={closeModal}
             busy={busy}
@@ -404,6 +433,8 @@ export function BacklogSection({
             initial={modalMode.item}
             roadmapItems={roadmapItems}
             featureActions={featureActions}
+            epicItems={epicItems.filter((epic) => epic.id !== modalMode.item.id)}
+            epicHierarchyEnabled={epicHierarchyEnabled}
             onSubmit={handleEditSubmit}
             onCancel={closeModal}
             busy={busy}

frontend/src/components/EpicParentSelect.jsx

@@ -0,0 +1,24 @@
+export function EpicParentSelect({ epicItems = [], defaultValue = '', disabled = false }) {
+  if (!epicItems.length) {
+    return (
+      <label>
+        Epic (optional)
+        <p className="muted form-hint">Lege zuerst ein Epic an, um Stories zuzuordnen.</p>
+      </label>
+    )
+  }
+
+  return (
+    <label>
+      Epic (optional)
+      <select name="parent_backlog_id" defaultValue={defaultValue || ''} disabled={disabled}>
+        <option value="">— kein Epic —</option>
+        {epicItems.map((epic) => (
+          <option key={epic.id} value={epic.id}>
+            {epic.title}
+          </option>
+        ))}
+      </select>
+    </label>
+  )
+}

frontend/src/constants/status.js

@@ -62,7 +62,9 @@ export const BACKLOG_STATUS_LABELS = {
 }
 
 export const BACKLOG_ITEM_KINDS = ['story', 'bug', 'issue']
+export const BACKLOG_ITEM_KINDS_WITH_EPIC = ['epic', 'story', 'bug', 'issue']
 export const BACKLOG_ITEM_KIND_LABELS = {
+  epic: 'Epic',
   story: 'Story',
   bug: 'Bug',
   issue: 'Issue',

frontend/src/utils/backlogTree.js

@@ -0,0 +1,53 @@
+import { sortByOrder } from './reorder.js'
+
+/**
+ * Flache Anzeige-Reihenfolge: Epics an Wurzel, Stories/Bugs/Issues eingerückt darunter.
+ * @param {Array<{ id: string, item_kind?: string, parent_backlog_id?: string | null, status?: string }>} items
+ * @returns {Array<{ item: object, depth: number }>}
+ */
+export function buildBacklogDisplayRows(items) {
+  const active = sortByOrder((items || []).filter((item) => item.status !== 'converted'))
+  const childrenByEpic = new Map()
+  const roots = []
+
+  for (const item of active) {
+    if (item.parent_backlog_id) {
+      const list = childrenByEpic.get(item.parent_backlog_id) || []
+      list.push(item)
+      childrenByEpic.set(item.parent_backlog_id, list)
+    } else {
+      roots.push(item)
+    }
+  }
+
+  const rows = []
+  const linkedChildIds = new Set()
+
+  for (const root of roots) {
+    rows.push({ item: root, depth: 0 })
+    if (root.item_kind === 'epic') {
+      const children = sortByOrder(childrenByEpic.get(root.id) || [])
+      for (const child of children) {
+        linkedChildIds.add(child.id)
+        rows.push({ item: child, depth: 1 })
+      }
+    }
+  }
+
+  for (const item of active) {
+    if (item.parent_backlog_id && !linkedChildIds.has(item.id)) {
+      rows.push({ item, depth: 0 })
+    }
+  }
+
+  return rows
+}
+
+/**
+ * @param {Array<{ id: string, item_kind?: string, status?: string }>} items
+ */
+export function listEpicBacklogItems(items) {
+  return (items || []).filter(
+    (item) => item.item_kind === 'epic' && item.status !== 'converted',
+  )
+}

frontend/src/utils/backlogTree.test.js

@@ -0,0 +1,28 @@
+import { describe, expect, it } from 'vitest'
+import { buildBacklogDisplayRows, listEpicBacklogItems } from './backlogTree.js'
+
+describe('backlogTree', () => {
+  it('gruppiert Stories unter Epic', () => {
+    const items = [
+      { id: 'e1', title: 'Epic A', item_kind: 'epic', sort_order: 0, status: 'accepted' },
+      { id: 's1', title: 'Story 1', item_kind: 'story', parent_backlog_id: 'e1', sort_order: 0, status: 'new' },
+      { id: 's2', title: 'Story 2', item_kind: 'story', parent_backlog_id: 'e1', sort_order: 10, status: 'new' },
+      { id: 'x1', title: 'Los', item_kind: 'story', sort_order: 20, status: 'new' },
+    ]
+    const rows = buildBacklogDisplayRows(items)
+    expect(rows.map((r) => [r.item.id, r.depth])).toEqual([
+      ['e1', 0],
+      ['s1', 1],
+      ['s2', 1],
+      ['x1', 0],
+    ])
+  })
+
+  it('listEpicBacklogItems filtert konvertierte Epics', () => {
+    const items = [
+      { id: 'e1', item_kind: 'epic', status: 'accepted' },
+      { id: 'e2', item_kind: 'epic', status: 'converted' },
+    ]
+    expect(listEpicBacklogItems(items).map((i) => i.id)).toEqual(['e1'])
+  })
+})