diff --git a/frontend/components/CollaborationRoom.vue b/frontend/components/CollaborationRoom.vue
index 773baf7a..08bf8ba5 100644
--- a/frontend/components/CollaborationRoom.vue
+++ b/frontend/components/CollaborationRoom.vue
@@ -1,9 +1,11 @@
 <script setup>
 const props = defineProps({ roomId: { type: String, required: true }, api: { type: Function, required: true }, base: { type: String, default: '/api/collaboration' }, embedded: { type: Boolean, default: false } })
 const emit = defineEmits(['changed', 'unauthorized'])
-const room = ref(null), messages = ref([]), members = ref([]), draft = ref(''), draftImage = ref(null), error = ref('')
+const room = ref(null), messages = ref([]), members = ref([]), error = ref('')
+// Guest access has separate credentials and must never reuse an internal user's drafts.
+const { draft, draftImage, draftSending, clearDraft, startDraftSend, finishDraftSend } = useChatDraft(() => `collaboration:${props.roomId}`, { persist: () => props.base === '/api/collaboration' })
 const loading = ref(false), sending = ref(false), olderLoading = ref(false), hasMore = ref(false), viewport = ref(null)
-let generation = 0, timer, polling = false, pending = null
+let generation = 0, timer, polling = false
 const endpoint = (id, suffix = '') => `${props.base}/rooms/${encodeURIComponent(id)}${suffix}`
 const merge = (incoming) => {
   const byId = new Map(messages.value.map(m => [m.id, m]))
@@ -20,7 +22,7 @@ const scroll = async () => { await nextTick(); if (viewport.value) viewport.valu
 function failed(e) {
   error.value = messageError(e)
   if ([401, 403, 404, 410].includes(e?.statusCode || e?.status)) {
-    room.value = null; messages.value = []; members.value = []; draftImage.value = null
+    room.value = null; messages.value = []; members.value = []
     if ((e?.statusCode || e?.status) === 401) emit('unauthorized')
   }
 }
@@ -32,7 +34,7 @@ async function read(id, version) {
 }
 async function load() {
   const version = ++generation, id = props.roomId
-  room.value = null; messages.value = []; members.value = []; draft.value = ''; draftImage.value = null; error.value = ''; pending = null
+  room.value = null; messages.value = []; members.value = []; error.value = ''
   loading.value = true; sending.value = false; olderLoading.value = false
   try {
     const [detail, result, people] = await Promise.all([props.api(endpoint(id)), props.api(endpoint(id, '/messages')), props.api(endpoint(id, '/members'))])
@@ -78,15 +80,18 @@ async function send() {
   const text = draft.value.trim(), image = draftImage.value
   if ((!text && !image) || sending.value || !room.value?.canSend) return
   const version = generation, id = props.roomId
-  if (!pending || pending.text !== text || pending.image !== image) pending = { text, image, clientId: crypto.randomUUID() }
+  const savedDraft = startDraftSend()
+  if (!savedDraft) return
+  const pending = { text, image, clientId: savedDraft.value.clientId }
   sending.value = true; error.value = ''
   try {
     const message = await props.api(endpoint(id, '/messages'), { method: 'POST', body: pending })
+    clearDraft(savedDraft)
     if (version !== generation) return
-    merge([message]); draft.value = ''; draftImage.value = null; pending = null
+    merge([message])
     await scroll(); await read(id, version)
   } catch (e) { if (version === generation) failed(e) }
-  finally { if (version === generation) sending.value = false }
+  finally { finishDraftSend(savedDraft); if (version === generation) sending.value = false }
 }
 const time = value => new Date(value).toLocaleString('de-DE', { dateStyle: 'short', timeStyle: 'short' })
 watch(() => props.roomId, load, { immediate: true })
@@ -126,6 +131,6 @@ onBeforeUnmount(() => { ++generation; clearInterval(timer) })
       </div>
       </ChatReactions>
     </div>
-    <ChatComposer v-if="room" :key="roomId" v-model="draft" v-model:image="draftImage" :busy="sending" :disabled="!room.canSend" :placeholder="room.canSend ? 'Nachricht schreiben …' : 'Dieser Unterraum ist nur lesbar'" @send="send" />
+    <ChatComposer v-if="room" :key="roomId" v-model="draft" v-model:image="draftImage" :busy="sending || draftSending" :disabled="!room.canSend" :placeholder="room.canSend ? 'Nachricht schreiben …' : 'Dieser Unterraum ist nur lesbar'" @send="send" />
   </section>
 </template>
diff --git a/frontend/composables/useChatDraft.js b/frontend/composables/useChatDraft.js
new file mode 100644
index 00000000..0a56ace4
--- /dev/null
+++ b/frontend/composables/useChatDraft.js
@@ -0,0 +1,43 @@
+export function useChatDraft(roomKey, { persist = true } = {}) {
+    const auth = useAuthStore()
+    const temp = useTempStore()
+    const apiBase = useRuntimeConfig().public.apiBase
+    const localDraft = ref(null)
+    const key = computed(() => {
+        const room = toValue(roomKey), user = auth.user?.id || auth.user?.user_id
+        return toValue(persist) && room && user && auth.activeTenant
+            ? JSON.stringify([apiBase, user, String(auth.activeTenant), auth.profile?.id || '', room])
+            : null
+    })
+    watch([key, () => toValue(roomKey), () => auth.user?.id || auth.user?.user_id,
+        () => auth.activeTenant, () => auth.profile?.id], () => { localDraft.value = null }, { flush: 'sync' })
+    const current = () => key.value ? temp.getChatDraft(key.value) : localDraft.value
+    function update(patch) {
+        const value = { text: '', image: null, ...current(), ...patch, clientId: crypto.randomUUID() }
+        const next = value.text || value.image ? value : null
+        if (key.value) temp.setChatDraft(key.value, next)
+        else localDraft.value = next
+    }
+    const draft = computed({ get: () => current()?.text || '', set: text => update({ text }) })
+    const draftImage = computed({ get: () => current()?.image || null, set: image => update({ image }) })
+    const draftSending = computed(() => !!key.value && temp.isChatDraftSending(key.value))
+    const captureDraft = () => ({ key: key.value, value: current() })
+    function startDraftSend() {
+        if (draftSending.value) return null
+        const snapshot = captureDraft()
+        if (!snapshot.value) return null
+        if (snapshot.key) temp.startChatDraftSend(snapshot.key, snapshot.value.clientId)
+        return snapshot
+    }
+    function finishDraftSend(snapshot) {
+        if (snapshot.key) temp.finishChatDraftSend(snapshot.key, snapshot.value.clientId)
+    }
+    function clearDraft(snapshot) {
+        const saved = snapshot.key ? temp.getChatDraft(snapshot.key) : localDraft.value
+        // A late send response must only remove the draft that was actually sent.
+        if (!snapshot.value || saved?.clientId !== snapshot.value.clientId) return
+        if (snapshot.key) temp.setChatDraft(snapshot.key, null)
+        else localDraft.value = null
+    }
+    return { draft, draftImage, draftSending, captureDraft, clearDraft, startDraftSend, finishDraftSend }
+}
diff --git a/frontend/pages/communication/chat.vue b/frontend/pages/communication/chat.vue
index bfd7f196..15af1ca9 100644
--- a/frontend/pages/communication/chat.vue
+++ b/frontend/pages/communication/chat.vue
@@ -7,7 +7,7 @@ const router = useRouter()
 
 const baseRooms = ref([]), projectRooms = ref([]), directRooms = ref([]), collaborationRooms = ref([])
 const invitations = ref([]), invitationBusy = ref(''), collaborationError = ref(''), listError = ref('')
-const unreadRooms = ref({}), messages = ref([]), members = ref([]), draft = ref(''), draftImage = ref(null)
+const unreadRooms = ref({}), messages = ref([]), members = ref([])
 const requestedRoom = () => typeof route.query.room === 'string' ? route.query.room : 'allgemein'
 const activeRoomKey = ref(requestedRoom())
 const loading = ref(true), roomLoading = ref(false), sending = ref(false), creating = ref(false)
@@ -48,8 +48,9 @@ const groupedRooms = computed(() => ['Räume', 'Projekte', 'Direktnachrichten',
 const activeRoom = computed(() => visibleRooms.value.find(room => room.key === activeRoomKey.value) || null)
 const isCollaboration = computed(() => activeRoom.value?.source === 'collaboration')
 const isInternal = computed(() => activeRoom.value?.source === 'internal')
+const { draft, draftImage, draftSending, clearDraft, startDraftSend, finishDraftSend } = useChatDraft(() => isInternal.value ? activeRoomKey.value : '')
 
-function clearMessages() { messages.value = []; members.value = []; draft.value = ''; draftImage.value = null; syncAfterId = 0; roomLoading.value = false; sending.value = false }
+function clearMessages() { messages.value = []; members.value = []; syncAfterId = 0; roomLoading.value = false; sending.value = false }
 function mergeMessages(incoming) {
   const byId = new Map(messages.value.map(message => [message.id, message]))
   for (const message of incoming || []) byId.set(message.id, message)
@@ -210,14 +211,17 @@ async function respondToInvitation(id, accept) {
 async function sendMessage() {
   const text = draft.value.trim(), image = draftImage.value, request = selection()
   if ((!text && !image) || sending.value || !isInternal.value || !activeRoom.value?.exists) return
-  sending.value = true; draft.value = ''
+  const savedDraft = startDraftSend()
+  if (!savedDraft) return
+  sending.value = true
   try {
     const message = await $api(nativeEndpoint(request.key, '/messages'), { method: 'POST', body: { text, ...(image ? { image } : {}) } })
+    clearDraft(savedDraft)
     if (!currentSelection(request)) return
-    draftImage.value = null; mergeMessages([message]); await markRead(request); await scrollToBottom(request)
+    mergeMessages([message]); await markRead(request); await scrollToBottom(request)
   } catch (error) {
-    if (currentSelection(request)) { draft.value = text; toast.add({ title: errorMessage(error), color: 'error' }) }
-  } finally { if (currentSelection(request)) sending.value = false }
+    if (currentSelection(request)) toast.add({ title: errorMessage(error), color: 'error' })
+  } finally { finishDraftSend(savedDraft); if (currentSelection(request)) sending.value = false }
 }
 async function pollMessages() {
   if (pollBusy || loading.value || roomLoading.value || document.hidden || !isInternal.value || !activeRoom.value?.exists) return
@@ -386,7 +390,7 @@ onBeforeUnmount(() => {
           </ChatReactions>
         </div>
 
-        <ChatComposer :key="`${session}:${activeRoomKey}`" v-model="draft" v-model:image="draftImage" :busy="sending" :disabled="!activeRoom?.exists || roomLoading" @send="sendMessage" />
+        <ChatComposer :key="`${session}:${activeRoomKey}`" v-model="draft" v-model:image="draftImage" :busy="sending || draftSending" :disabled="!activeRoom?.exists || roomLoading" @send="sendMessage" />
       </main>
 
       <aside v-if="!isCollaboration" class="hidden min-h-0 overflow-y-auto border-l border-gray-200 p-4 lg:block">
diff --git a/frontend/stores/temp.js b/frontend/stores/temp.js
index 3ab82838..ecdb6303 100644
--- a/frontend/stores/temp.js
+++ b/frontend/stores/temp.js
@@ -10,6 +10,71 @@ export const useTempStore = defineStore('temp', () => {
     const pages = ref({})
     const settings = ref({})
 
+    // Drafts stay local: temp_config is also returned in tenant profile lists.
+    const chatDrafts = ref({})
+    const sendingChatDrafts = ref({})
+    const loadedChatDrafts = new Set()
+    const draftStoragePrefix = 'fedeo:chat-draft:v1:'
+    const toast = useToast()
+    let draftStorageWarningShown = false
+
+    function getChatDraft(key) {
+        if (!loadedChatDrafts.has(key)) {
+            loadedChatDrafts.add(key)
+            try {
+                const saved = JSON.parse(sessionStorage.getItem(draftStoragePrefix + key) || 'null')
+                if (saved && typeof saved.text === 'string' && typeof saved.clientId === 'string'
+                    && saved.text.length <= 10000 && (!saved.image || (
+                        typeof saved.image.name === 'string' && typeof saved.image.dataUrl === 'string'
+                        && saved.image.dataUrl.length <= 480000
+                        && /^data:image\/(jpeg|png|webp);base64,[A-Za-z0-9+/=]+$/.test(saved.image.dataUrl)
+                    ))) chatDrafts.value[key] = saved
+            } catch { /* Disabled storage or an invalid entry must not block the chat. */ }
+        }
+        return chatDrafts.value[key] || null
+    }
+
+    function setChatDraft(key, draft) {
+        loadedChatDrafts.add(key)
+        if (draft) chatDrafts.value[key] = draft
+        else delete chatDrafts.value[key]
+        try {
+            if (draft) sessionStorage.setItem(draftStoragePrefix + key, JSON.stringify(draft))
+            else sessionStorage.removeItem(draftStoragePrefix + key)
+        } catch {
+            // Do not restore an older version after a failed storage update.
+            try { sessionStorage.removeItem(draftStoragePrefix + key) } catch {}
+            if (!draftStorageWarningShown) {
+                draftStorageWarningShown = true
+                toast.add({ title: 'Entwurf nur vorübergehend gespeichert', description: 'Der Browserspeicher ist voll oder gesperrt. Bis zum Neuladen bleibt dein Entwurf im Chat erhalten.', color: 'warning' })
+            }
+        }
+    }
+
+    function isChatDraftSending(key) {
+        return !!sendingChatDrafts.value[key]
+    }
+
+    function startChatDraftSend(key, clientId) {
+        sendingChatDrafts.value[key] = clientId
+    }
+
+    function finishChatDraftSend(key, clientId) {
+        if (sendingChatDrafts.value[key] === clientId) delete sendingChatDrafts.value[key]
+    }
+
+    watch(() => auth.user?.id || auth.user?.user_id, (user, previous) => {
+        if (!previous || user === previous) return
+        chatDrafts.value = {}
+        sendingChatDrafts.value = {}
+        loadedChatDrafts.clear()
+        try {
+            for (const key of Object.keys(sessionStorage)) {
+                if (key.startsWith(draftStoragePrefix)) sessionStorage.removeItem(key)
+            }
+        } catch { /* Storage may be unavailable. In-memory drafts are still cleared. */ }
+    }, { flush: 'sync' })
+
     const storeTempConfig = async () => {
         const config = {
             searchStrings: searchStrings.value,
@@ -92,6 +157,11 @@ export const useTempStore = defineStore('temp', () => {
     }
 
     return {
+        getChatDraft,
+        setChatDraft,
+        isChatDraftSending,
+        startChatDraftSend,
+        finishChatDraftSend,
         setStoredTempConfig,
         searchStrings,
         modifySearchString,
diff --git a/frontend/tests/chat-collaboration.test.cjs b/frontend/tests/chat-collaboration.test.cjs
index 79bf8d98..ccf7be67 100644
--- a/frontend/tests/chat-collaboration.test.cjs
+++ b/frontend/tests/chat-collaboration.test.cjs
@@ -3,6 +3,7 @@ const assert = require('node:assert/strict')
 const fs = require('node:fs')
 const vm = require('node:vm')
 const vue = require('vue')
+const { createDraftHarness } = require('./helpers/chat-drafts.cjs')
 
 const settle = () => new Promise(setImmediate)
 const deferred = () => {
@@ -33,6 +34,7 @@ function fixture(override = () => undefined) {
 
 function setup(api = fixture(), query = {}) {
   const auth = vue.reactive({ user: { id: 'user-1' }, activeTenant: '1' })
+  const drafts = createDraftHarness({ auth })
   const route = vue.reactive({ query })
   const calls = [], toasts = [], timers = new Map()
   const listeners = new Map()
@@ -47,6 +49,7 @@ function setup(api = fixture(), query = {}) {
     ref: vue.ref, reactive: vue.reactive, computed: vue.computed, watch: vue.watch, nextTick: vue.nextTick,
     useToast: () => ({ add: item => toasts.push(item) }),
     useAuthStore: () => auth, useRoute: () => route,
+    useChatDraft: drafts.useChatDraft,
     useRouter: () => ({ replace: async location => { route.query = location.query } }),
     useNuxtApp: () => ({ $api: (url, options) => { calls.push({ url, options }); return api(url, options) } }),
     onMounted: handler => { mount = handler }, onBeforeUnmount: handler => { unmount = handler },
@@ -54,7 +57,7 @@ function setup(api = fixture(), query = {}) {
     clearInterval: id => timers.delete(id), document,
   })
   scope.run(() => vm.runInContext(source, context))
-  return { auth, route, calls, toasts, timers, listeners, document, mount, close: () => { unmount(); scope.stop() }, run: code => vm.runInContext(code, context) }
+  return { auth, route, calls, toasts, timers, listeners, document, mount, drafts, close: () => { unmount(); scope.stop(); drafts.close() }, run: code => vm.runInContext(code, context) }
 }
 
 test('only member rooms enter normal chat, with separate keys, groups and unread counts', async t => {
@@ -377,3 +380,69 @@ test('native image-only sends retain the draft after an error and clear it after
   assert.equal(ui.run('draftImage.value'), null)
   assert.ok(ui.calls.some(c => c.options?.body?.image?.name === 'Bild'))
 })
+
+test('native drafts survive switching chats, hiding a room and reloading its history', async t => {
+  const ui = setup(fixture(url => url.endsWith('/project-rooms') ? { rooms: [{ key: 'project_1', exists: true, type: 'project' }] } : undefined))
+  t.after(ui.close)
+  ui.mount()
+  await settle()
+  ui.run('draft.value = "  Hallo\\nWelt 👋  "; draftImage.value = { dataUrl: "data:image/webp;base64,AAAA", name: "Skizze" }')
+  await ui.run('selectRoom(decoratedRooms.value.find(r => r.key === "project_1"))')
+  assert.equal(ui.run('draft.value'), '')
+  assert.equal(ui.run('draftImage.value'), null)
+  ui.run('draft.value = "Projektentwurf"')
+  await ui.run('selectRoom(decoratedRooms.value.find(r => r.key === "allgemein"))')
+  assert.equal(ui.run('draft.value'), '  Hallo\nWelt 👋  ')
+  assert.equal(ui.run('draftImage.value.name'), 'Skizze')
+  await ui.run('loadActiveRoom()')
+  assert.equal(ui.run('draft.value'), '  Hallo\nWelt 👋  ')
+  await ui.run('setRoomHidden(activeRoom.value, true)')
+  assert.equal(ui.run('draft.value'), 'Projektentwurf')
+  await ui.run('setRoomHidden(hiddenRooms.value[0], false)')
+  assert.equal(ui.run('draft.value'), '  Hallo\nWelt 👋  ')
+})
+
+test('failed sends retain the exact draft after switching away, and late success clears only the sent room', async t => {
+  const pending = deferred()
+  let fail = true
+  const ui = setup(fixture((url, options) => {
+    if (url.endsWith('/messages') && options?.method === 'POST') {
+      if (fail) throw { data: { message: 'Offline' } }
+      return pending.promise
+    }
+  }))
+  t.after(ui.close)
+  ui.mount()
+  await settle()
+  ui.run('draft.value = "  Noch nicht fertig\\n  "')
+  await ui.run('sendMessage()')
+  assert.equal(ui.run('draft.value'), '  Noch nicht fertig\n  ')
+  fail = false
+  const sending = ui.run('sendMessage()')
+  await ui.run('selectRoom(decoratedRooms.value.find(r => r.source === "collaboration"))')
+  pending.resolve({ id: 2, body: 'Noch nicht fertig' })
+  await sending
+  await ui.run('selectRoom(decoratedRooms.value.find(r => r.key === "allgemein"))')
+  assert.equal(ui.run('draft.value'), '')
+  assert.equal(Object.keys(ui.drafts.storage).length, 0)
+})
+
+test('editing a room after returning to a pending send preserves the new draft', async t => {
+  const pending = deferred()
+  const ui = setup(fixture((url, options) => url.endsWith('/messages') && options?.method === 'POST' ? pending.promise : undefined))
+  t.after(ui.close)
+  ui.mount()
+  await settle()
+  ui.run('draft.value = "Vorheriger Entwurf"')
+  const sending = ui.run('sendMessage()')
+  await ui.run('selectRoom(decoratedRooms.value.find(r => r.source === "collaboration"))')
+  await ui.run('selectRoom(decoratedRooms.value.find(r => r.key === "allgemein"))')
+  assert.equal(ui.run('draftSending.value'), true)
+  await ui.run('sendMessage()')
+  assert.equal(ui.calls.filter(({ url, options }) => url.endsWith('/messages') && options?.method === 'POST').length, 1)
+  ui.run('draft.value = "Weitergeschrieben"')
+  pending.resolve({ id: 2, body: 'Vorheriger Entwurf' })
+  await sending
+  assert.equal(ui.run('draft.value'), 'Weitergeschrieben')
+  assert.equal(ui.run('draftSending.value'), false)
+})
diff --git a/frontend/tests/chat-drafts.test.cjs b/frontend/tests/chat-drafts.test.cjs
new file mode 100644
index 00000000..e1d7e4f0
--- /dev/null
+++ b/frontend/tests/chat-drafts.test.cjs
@@ -0,0 +1,123 @@
+const { test } = require('node:test')
+const assert = require('node:assert/strict')
+const vue = require('vue')
+const { createDraftHarness, memoryStorage } = require('./helpers/chat-drafts.cjs')
+const image = { dataUrl: 'data:image/webp;base64,AAAA', name: 'Skizze.webp' }
+
+test('text and image drafts survive room changes and a browser reload in the same session', t => {
+  const storage = memoryStorage(), first = createDraftHarness({ storage })
+  t.after(first.close)
+  const room = vue.ref('allgemein'), composer = first.useChatDraft(room)
+  composer.draft.value = '  Hallo\nWelt 👋  '
+  composer.draftImage.value = image
+  room.value = 'project_1'
+  assert.equal(composer.draft.value, '')
+  assert.equal(composer.draftImage.value, null)
+  composer.draft.value = 'Projektentwurf'
+  room.value = 'allgemein'
+  assert.equal(composer.draft.value, '  Hallo\nWelt 👋  ')
+  assert.equal(composer.draftImage.value.name, image.name)
+
+  const reloaded = createDraftHarness({ storage })
+  t.after(reloaded.close)
+  const restored = reloaded.useChatDraft('allgemein')
+  assert.equal(restored.draft.value, composer.draft.value)
+  assert.equal(restored.draftImage.value.dataUrl, image.dataUrl)
+  assert.equal(restored.captureDraft().value.clientId, composer.captureDraft().value.clientId)
+  assert.equal(reloaded.useChatDraft('project_1').draft.value, 'Projektentwurf')
+  assert.equal(first.calls.length, 0)
+})
+
+test('tenant and profile scopes cannot read each other; logout removes the session drafts', t => {
+  const ui = createDraftHarness()
+  t.after(ui.close)
+  const composer = ui.useChatDraft('allgemein')
+  composer.draft.value = 'Privater Entwurf'
+  ui.auth.activeTenant = '2'
+  assert.equal(composer.draft.value, '')
+  composer.draft.value = 'Mandant 2'
+  ui.auth.activeTenant = '1'
+  assert.equal(composer.draft.value, 'Privater Entwurf')
+  ui.auth.profile = { id: 'other-profile' }
+  assert.equal(composer.draft.value, '')
+  ui.auth.profile = { id: 'profile-1' }
+  assert.equal(composer.draft.value, 'Privater Entwurf')
+  ui.auth.user = { id: 'another-user' }
+  assert.equal(composer.draft.value, '')
+  assert.equal(Object.keys(ui.storage).length, 0)
+  composer.draft.value = 'Neuer Benutzer'
+  ui.auth.user = null
+  assert.equal(composer.draft.value, '')
+  assert.equal(Object.keys(ui.storage).length, 0)
+})
+
+test('successful sends remove only the captured version, even after changing rooms', t => {
+  const ui = createDraftHarness()
+  t.after(ui.close)
+  const room = vue.ref('allgemein'), composer = ui.useChatDraft(room)
+  composer.draft.value = 'Gesendet'
+  const sent = composer.captureDraft()
+  room.value = 'project_1'
+  composer.draft.value = 'Noch nicht gesendet'
+  composer.clearDraft(sent)
+  assert.equal(composer.draft.value, 'Noch nicht gesendet')
+  room.value = 'allgemein'
+  assert.equal(composer.draft.value, '')
+  composer.draftImage.value = image
+  const older = composer.captureDraft()
+  composer.draft.value = 'Neuer Text zum Bild'
+  composer.clearDraft(older)
+  assert.equal(composer.draft.value, 'Neuer Text zum Bild')
+  assert.equal(composer.draftImage.value.name, image.name)
+  composer.clearDraft(composer.captureDraft())
+  assert.equal(composer.draft.value, '')
+  assert.equal(composer.draftImage.value, null)
+})
+
+test('empty drafts are removed and never enter the shared profile temp_config', async t => {
+  const ui = createDraftHarness()
+  t.after(ui.close)
+  const composer = ui.useChatDraft('direct_user-2')
+  composer.draft.value = 'Geheim'
+  ui.store.modifySearchString('contacts', 'Beispiel')
+  assert.equal(JSON.stringify(ui.calls).includes('Geheim'), false)
+  ui.store.setStoredTempConfig({ settings: { density: 'compact' } })
+  assert.equal(composer.draft.value, 'Geheim')
+  composer.draft.value = ''
+  assert.equal(Object.keys(ui.storage).length, 0)
+})
+
+test('guest conversations never reuse internal drafts and keep temporary text through a retry', t => {
+  const ui = createDraftHarness()
+  t.after(ui.close)
+  ui.useChatDraft('collaboration:one').draft.value = 'Interner Entwurf'
+  const room = vue.ref('collaboration:one'), guest = ui.useChatDraft(room, { persist: false })
+  assert.equal(guest.draft.value, '')
+  guest.draft.value = 'Gastentwurf'
+  assert.equal(guest.draft.value, 'Gastentwurf')
+  room.value = 'collaboration:two'
+  assert.equal(guest.draft.value, '')
+  assert.equal(Object.values(ui.storage).some(value => value.includes('Gastentwurf')), false)
+})
+
+test('corrupt or unavailable browser storage does not prevent writing or sending', t => {
+  const storage = memoryStorage(), initial = createDraftHarness({ storage })
+  t.after(initial.close)
+  initial.useChatDraft('allgemein').draft.value = 'Alt'
+  storage[Object.keys(storage)[0]] = 'invalid json'
+  const corrupt = createDraftHarness({ storage })
+  t.after(corrupt.close)
+  assert.equal(corrupt.useChatDraft('allgemein').draft.value, '')
+  const blocked = createDraftHarness({ storage: {
+    getItem() { throw Error('Blocked') }, setItem() { throw Error('Quota exceeded') }, removeItem() { throw Error('Blocked') },
+  } })
+  t.after(blocked.close)
+  const composer = blocked.useChatDraft('allgemein')
+  composer.draft.value = 'Im Speicher'
+  composer.draftImage.value = image
+  assert.equal(composer.draft.value, 'Im Speicher')
+  assert.equal(composer.draftImage.value.name, image.name)
+  assert.equal(blocked.toasts.length, 1)
+  composer.clearDraft(composer.captureDraft())
+  assert.equal(composer.draft.value, '')
+})
diff --git a/frontend/tests/chat-media.test.cjs b/frontend/tests/chat-media.test.cjs
index ef0a3215..5b5cdf68 100644
--- a/frontend/tests/chat-media.test.cjs
+++ b/frontend/tests/chat-media.test.cjs
@@ -3,6 +3,7 @@ const assert = require('node:assert/strict')
 const fs = require('node:fs')
 const vm = require('node:vm')
 const vue = require('vue')
+const { createDraftHarness } = require('./helpers/chat-drafts.cjs')
 const settle = () => new Promise(setImmediate)
 const deferred = () => { let resolve; return { promise: new Promise(done => { resolve = done }), resolve: value => resolve(value) } }
 
@@ -89,3 +90,62 @@ test('image display rejects external URLs and ignores responses after a room cha
   await ui.run('load()')
   assert.equal(ui.run('dataUrl.value'), 'data:image/webp;base64,AAAA')
 })
+
+function collaborationApi(onSend) {
+  return async (url, options) => {
+    if (options?.method === 'POST' && url.endsWith('/messages')) return onSend(options.body)
+    if (url.endsWith('/messages')) return { messages: [], hasMore: false }
+    if (url.endsWith('/members')) return { members: [] }
+    if (url.endsWith('/read')) return {}
+    return { canSend: true, name: 'Partnerchat' }
+  }
+}
+
+test('collaboration drafts retain text, images and the retry ID when reopening after a failed send', async t => {
+  const drafts = createDraftHarness(), attempts = []
+  t.after(drafts.close)
+  let fail = true
+  const props = { roomId: 'shared', base: '/api/collaboration', api: collaborationApi(body => {
+    attempts.push(body)
+    if (fail) throw { data: { message: 'Offline' } }
+    return { id: 'message-1', seq: 1, own: true, clientId: body.clientId, body: body.text }
+  }) }
+  const first = setup('CollaborationRoom', props, { useChatDraft: drafts.useChatDraft })
+  await settle()
+  first.run('draft.value = "  Partnerentwurf\\n  "; draftImage.value = { dataUrl: "data:image/webp;base64,AAAA", name: "Plan" }')
+  await first.run('send()')
+  assert.equal(first.run('draft.value'), '  Partnerentwurf\n  ')
+  assert.equal(first.run('draftImage.value.name'), 'Plan')
+  await first.run('load()')
+  assert.equal(first.run('draft.value'), '  Partnerentwurf\n  ')
+  first.close()
+  const second = setup('CollaborationRoom', props, { useChatDraft: drafts.useChatDraft })
+  t.after(second.close)
+  await settle()
+  assert.equal(second.run('draft.value'), '  Partnerentwurf\n  ')
+  fail = false
+  await second.run('send()')
+  assert.equal(attempts[0].clientId, attempts[1].clientId)
+  assert.equal(second.run('draft.value'), '')
+  assert.equal(second.run('draftImage.value'), null)
+  assert.equal(Object.keys(drafts.storage).length, 0)
+})
+
+test('collaboration send completion after unmount does not erase a newer draft in the same room', async t => {
+  const drafts = createDraftHarness(), pending = deferred()
+  t.after(drafts.close)
+  const props = { roomId: 'shared', base: '/api/collaboration', api: collaborationApi(() => pending.promise) }
+  const first = setup('CollaborationRoom', props, { useChatDraft: drafts.useChatDraft })
+  await settle()
+  first.run('draft.value = "Gesendet"')
+  const sending = first.run('send()')
+  first.close()
+  const second = setup('CollaborationRoom', props, { useChatDraft: drafts.useChatDraft })
+  t.after(second.close)
+  await settle()
+  second.run('draft.value = "Neuer Entwurf"')
+  pending.resolve({ id: 'message-1', seq: 1, body: 'Gesendet' })
+  await sending
+  assert.equal(second.run('draft.value'), 'Neuer Entwurf')
+  assert.equal(second.run('messages.value.length'), 0)
+})
diff --git a/frontend/tests/helpers/chat-drafts.cjs b/frontend/tests/helpers/chat-drafts.cjs
new file mode 100644
index 00000000..f5a10e70
--- /dev/null
+++ b/frontend/tests/helpers/chat-drafts.cjs
@@ -0,0 +1,36 @@
+const fs = require('node:fs')
+const vm = require('node:vm')
+const { randomUUID } = require('node:crypto')
+const vue = require('vue')
+
+function memoryStorage() {
+  const storage = Object.create(null)
+  Object.defineProperties(storage, {
+    getItem: { value: key => storage[key] ?? null },
+    setItem: { value: (key, value) => { storage[key] = value } },
+    removeItem: { value: key => { delete storage[key] } },
+  })
+  return storage
+}
+
+function createDraftHarness({ auth = vue.reactive({ user: { id: 'user-1' }, activeTenant: '1', profile: { id: 'profile-1' } }), storage = memoryStorage() } = {}) {
+  const scope = vue.effectScope(), toasts = [], calls = []
+  const context = vm.createContext({ ...vue, crypto: { randomUUID }, sessionStorage: storage,
+    defineStore: (_, setup) => setup,
+    useAuthStore: () => auth,
+    useRuntimeConfig: () => ({ public: { apiBase: 'https://api.example.test' } }),
+    useToast: () => ({ add: toast => toasts.push(toast) }),
+    useNuxtApp: () => ({ $api: async (url, options) => { calls.push({ url, options }) } }),
+  })
+  const storeSource = fs.readFileSync(`${__dirname}/../../stores/temp.js`, 'utf8').replace(/^import .*$/mg, '').replace('export const', 'const')
+  const store = scope.run(() => vm.runInContext(`${storeSource}\nuseTempStore()`, context))
+  context.useTempStore = () => store
+  const composable = fs.readFileSync(`${__dirname}/../../composables/useChatDraft.js`, 'utf8').replace('export function', 'function')
+  vm.runInContext(composable, context)
+  return { auth, storage, store, calls, toasts,
+    useChatDraft: (key, options) => scope.run(() => context.useChatDraft(key, options)),
+    close: () => scope.stop(),
+  }
+}
+
+module.exports = { createDraftHarness, memoryStorage }