diff --git a/frontend/src/components/PlanOutlineNav.jsx b/frontend/src/components/PlanOutlineNav.jsx
index 2d3c21d..404841c 100644
--- a/frontend/src/components/PlanOutlineNav.jsx
+++ b/frontend/src/components/PlanOutlineNav.jsx
@@ -5,13 +5,14 @@ import { listInitiativeActions } from '../api/initiatives.js'
 import { listInitiativeBacklog } from '../api/backlog.js'
 import { useProgramScope } from '../context/ProgramScopeContext.jsx'
 import { buildProjectsByParent } from '../utils/projectTree.js'
-import { projectPath, actionPath } from '../utils/routes.js'
+import { projectPath } from '../utils/routes.js'
 import {
   PLAN_OUTLINE_NODES,
   resolvePlanOutlineActiveKey,
   resolvePlanOutlineProjectId,
   resolvePlanOutlineActionId,
 } from '../plan/planOutlineNodes.js'
+import { PlanOutlineWorkTree } from './PlanOutlineWorkTree.jsx'
 
 function PlanOutlineProjectTree({ projects, parentId, activeProjectId, depth = 0 }) {
   const byParent = useMemo(() => buildProjectsByParent(projects), [projects])
@@ -217,23 +218,11 @@ export function PlanOutlineNav() {
                 />
               )}
               {hasActionList && workOpen && (
-                <ul className="analysis-split__nav-sublist">
-                  {openActions.map((action) => (
-                    <li key={action.id}>
-                      <NavLink
-                        to={actionPath(action.id)}
-                        className={({ isActive }) =>
-                          'analysis-split__nav-link analysis-split__nav-link--nested' +
-                          (isActive || activeActionId === action.id
-                            ? ' analysis-split__nav-link--active'
-                            : '')
-                        }
-                      >
-                        {action.title}
-                      </NavLink>
-                    </li>
-                  ))}
-                </ul>
+                <PlanOutlineWorkTree
+                  openActions={openActions}
+                  activeActionId={activeActionId}
+                  enabled={workOpen}
+                />
               )}
             </li>
           )
diff --git a/frontend/src/components/PlanOutlineWorkTree.jsx b/frontend/src/components/PlanOutlineWorkTree.jsx
new file mode 100644
index 0000000..be085c1
--- /dev/null
+++ b/frontend/src/components/PlanOutlineWorkTree.jsx
@@ -0,0 +1,188 @@
+import { useEffect, useMemo, useState } from 'react'
+import { NavLink } from 'react-router-dom'
+import { listActionTasks } from '../api/tasks.js'
+import { actionPath } from '../utils/routes.js'
+import { buildTasksByParent, countOpenTasks, MAX_TASK_UI_DEPTH } from '../utils/taskTree.js'
+
+function actionTasksHref(actionId) {
+  return `${actionPath(actionId)}#tasks`
+}
+
+function PlanOutlineTaskTree({
+  tasksByParent,
+  parentId,
+  actionId,
+  depth,
+  expandedTaskIds,
+  onToggleTask,
+  activeActionId,
+}) {
+  const nodes = (tasksByParent.get(parentId || '') || []).filter(
+    (task) => task.status !== 'done' && task.status !== 'discarded',
+  )
+
+  if (nodes.length === 0 || depth > MAX_TASK_UI_DEPTH) {
+    return null
+  }
+
+  return (
+    <ul className="analysis-split__nav-sublist">
+      {nodes.map((task) => {
+        const childNodes = tasksByParent.get(task.id) || []
+        const hasChildren = childNodes.some(
+          (child) => child.status !== 'done' && child.status !== 'discarded',
+        )
+        const canExpand = hasChildren && depth < MAX_TASK_UI_DEPTH
+        const isExpanded = expandedTaskIds.has(task.id)
+
+        return (
+          <li key={task.id}>
+            <div className="analysis-split__nav-row">
+              {canExpand && (
+                <button
+                  type="button"
+                  className="analysis-split__nav-toggle"
+                  aria-expanded={isExpanded}
+                  aria-label={isExpanded ? 'Aufgaben einklappen' : 'Aufgaben ausklappen'}
+                  onClick={() => onToggleTask(task.id)}
+                >
+                  {isExpanded ? '▾' : '▸'}
+                </button>
+              )}
+              <NavLink
+                to={actionTasksHref(actionId)}
+                className={({ isActive }) =>
+                  'analysis-split__nav-link analysis-split__nav-link--nested' +
+                  (depth >= 2 ? ' analysis-split__nav-link--depth-2' : '') +
+                  (isActive || activeActionId === actionId
+                    ? ' analysis-split__nav-link--active'
+                    : '')
+                }
+              >
+                {task.title}
+              </NavLink>
+            </div>
+            {canExpand && isExpanded && (
+              <PlanOutlineTaskTree
+                tasksByParent={tasksByParent}
+                parentId={task.id}
+                actionId={actionId}
+                depth={depth + 1}
+                expandedTaskIds={expandedTaskIds}
+                onToggleTask={onToggleTask}
+                activeActionId={activeActionId}
+              />
+            )}
+          </li>
+        )
+      })}
+    </ul>
+  )
+}
+
+function PlanOutlineActionNode({ action, tasks, activeActionId, defaultExpanded }) {
+  const [actionOpen, setActionOpen] = useState(defaultExpanded)
+  const [expandedTaskIds, setExpandedTaskIds] = useState(() => new Set())
+
+  const tasksByParent = useMemo(() => buildTasksByParent(tasks || []), [tasks])
+  const openTaskCount = useMemo(() => countOpenTasks(tasks || []), [tasks])
+  const hasOpenTasks = openTaskCount > 0
+
+  useEffect(() => {
+    setActionOpen(defaultExpanded)
+  }, [defaultExpanded])
+
+  function toggleTask(taskId) {
+    setExpandedTaskIds((prev) => {
+      const next = new Set(prev)
+      if (next.has(taskId)) next.delete(taskId)
+      else next.add(taskId)
+      return next
+    })
+  }
+
+  return (
+    <li>
+      <div className="analysis-split__nav-row">
+        {hasOpenTasks && (
+          <button
+            type="button"
+            className="analysis-split__nav-toggle"
+            aria-expanded={actionOpen}
+            aria-label={actionOpen ? 'Aufgaben einklappen' : 'Aufgaben ausklappen'}
+            onClick={() => setActionOpen((open) => !open)}
+          >
+            {actionOpen ? '▾' : '▸'}
+          </button>
+        )}
+        <NavLink
+          to={actionPath(action.id)}
+          className={({ isActive }) =>
+            'analysis-split__nav-link analysis-split__nav-link--nested' +
+            (isActive || activeActionId === action.id
+              ? ' analysis-split__nav-link--active'
+              : '')
+          }
+        >
+          {action.title}
+          {openTaskCount > 0 && (
+            <span className="analysis-split__nav-meta"> ({openTaskCount})</span>
+          )}
+        </NavLink>
+      </div>
+      {hasOpenTasks && actionOpen && (
+        <PlanOutlineTaskTree
+          tasksByParent={tasksByParent}
+          parentId=""
+          actionId={action.id}
+          depth={1}
+          expandedTaskIds={expandedTaskIds}
+          onToggleTask={toggleTask}
+          activeActionId={activeActionId}
+        />
+      )}
+    </li>
+  )
+}
+
+export function PlanOutlineWorkTree({ openActions, activeActionId, enabled }) {
+  const [tasksByAction, setTasksByAction] = useState({})
+  const actionIdsKey = useMemo(
+    () => openActions.map((action) => action.id).join(','),
+    [openActions],
+  )
+
+  useEffect(() => {
+    if (!enabled || openActions.length === 0) {
+      setTasksByAction({})
+      return undefined
+    }
+    let cancelled = false
+    Promise.all(
+      openActions.map((action) =>
+        listActionTasks(action.id)
+          .then((tasks) => [action.id, Array.isArray(tasks) ? tasks : []])
+          .catch(() => [action.id, []]),
+      ),
+    ).then((entries) => {
+      if (!cancelled) setTasksByAction(Object.fromEntries(entries))
+    })
+    return () => {
+      cancelled = true
+    }
+  }, [enabled, actionIdsKey, openActions])
+
+  return (
+    <ul className="analysis-split__nav-sublist">
+      {openActions.map((action) => (
+        <PlanOutlineActionNode
+          key={action.id}
+          action={action}
+          tasks={tasksByAction[action.id] || []}
+          activeActionId={activeActionId}
+          defaultExpanded={activeActionId === action.id}
+        />
+      ))}
+    </ul>
+  )
+}
diff --git a/frontend/src/components/TasksSection.jsx b/frontend/src/components/TasksSection.jsx
index 1710d8b..41ceaf3 100644
--- a/frontend/src/components/TasksSection.jsx
+++ b/frontend/src/components/TasksSection.jsx
@@ -95,7 +95,7 @@ export function TasksSection({ actionId, canManage, roadmapItems = [] }) {
   if (loading) return <p className="muted">Tasks werden geladen…</p>
 
   return (
-    <section className="card tasks-section">
+    <section className="card tasks-section" id="tasks">
       <div className="section-header">
         <div>
           <h3>Aufgaben</h3>
diff --git a/frontend/src/styles/program-chrome.css b/frontend/src/styles/program-chrome.css
index 47cdabe..02d426b 100644
--- a/frontend/src/styles/program-chrome.css
+++ b/frontend/src/styles/program-chrome.css
@@ -348,6 +348,17 @@
   font-weight: 500;
 }
 
+.analysis-split__nav-link--depth-2 {
+  font-size: 11px;
+  font-weight: 500;
+  opacity: 0.92;
+}
+
+.analysis-split__nav-meta {
+  font-weight: 400;
+  opacity: 0.85;
+}
+
 @media (max-width: 900px) {
   .analysis-split {
     grid-template-columns: 1fr;