diff --git a/apps/desktop/src/plugins/hermes-bots/plugin.js b/apps/desktop/src/plugins/hermes-bots/plugin.js
index 8f4b6d65ba..df8b4cdbd7 100644
--- a/apps/desktop/src/plugins/hermes-bots/plugin.js
+++ b/apps/desktop/src/plugins/hermes-bots/plugin.js
@@ -6203,6 +6203,10 @@ async function renameGroupChat(oldName, newName, members) {
   const all = { ...$groupChats.get() }
   const room = all[oldName]
 
+  if (room) {
+    migrateGroupComposerDraft(groupComposerDraftKey(oldName, room), groupComposerDraftKey(next, room))
+  }
+
   delete all[oldName]
 
   if (room) {
@@ -11301,11 +11305,131 @@ function GroupClarifyCard({ entry, members }) {
   })
 }
 
+// Group composer drafts are window-local UI state. They must survive pane
+// parking/re-registration and owner switches, but must never enter shared room
+// metadata (where another Desktop would see half-typed text or attachment
+// bytes). Current rooms key by immutable roomId; legacy rooms fall back to the
+// display name until they are upgraded.
+const groupComposerDrafts = new Map()
+
+function emptyGroupComposerDraft() {
+  return { activeReplyThread: null, main: '', pendingAttachments: {}, replies: {}, revision: 0 }
+}
+
+function groupComposerDraftKey(group, room) {
+  return groupChatRoomKey(group, room)
+}
+
+function groupComposerDraftSnapshot(key) {
+  return groupComposerDrafts.get(key) || emptyGroupComposerDraft()
+}
+
+function updateGroupComposerDraft(key, mutate) {
+  const current = groupComposerDraftSnapshot(key)
+  const next = mutate({
+    ...current,
+    pendingAttachments: Object.fromEntries(
+      Object.entries(current.pendingAttachments || {}).map(([thread, attachments]) => [
+        thread,
+        [...(attachments || [])]
+      ])
+    ),
+    replies: { ...(current.replies || {}) }
+  })
+
+  next.revision = current.revision + 1
+  groupComposerDrafts.delete(key)
+  groupComposerDrafts.set(key, next)
+
+  return next
+}
+
+function restoreGroupComposerDraft(key, expectedRevision, snapshot) {
+  const current = groupComposerDraftSnapshot(key)
+
+  if (current.revision !== expectedRevision) {
+    return null
+  }
+
+  const restored = {
+    ...snapshot,
+    pendingAttachments: Object.fromEntries(
+      Object.entries(snapshot.pendingAttachments || {}).map(([thread, attachments]) => [
+        thread,
+        [...(attachments || [])]
+      ])
+    ),
+    replies: { ...(snapshot.replies || {}) },
+    revision: current.revision + 1
+  }
+
+  groupComposerDrafts.set(key, restored)
+
+  return restored
+}
+
+function clearGroupComposerDraft(key) {
+  groupComposerDrafts.delete(key)
+}
+
+function migrateGroupComposerDraft(oldKey, newKey) {
+  if (oldKey === newKey || !groupComposerDrafts.has(oldKey)) {
+    return
+  }
+
+  if (!groupComposerDrafts.has(newKey)) {
+    groupComposerDrafts.set(newKey, groupComposerDrafts.get(oldKey))
+  }
+
+  groupComposerDrafts.delete(oldKey)
+}
+
 function GroupChatWorkspace({ group, members, onBack, visible = true }) {
   const rooms = useValue($groupChats)
   const allMeta = useValue($botMeta)
   const room = rooms[group] || { log: [], running: false }
-  const [draft, setDraft] = useState('')
+  const composerKey = groupComposerDraftKey(group, room)
+  const composerKeyRef = useRef(composerKey)
+  const [composerDraft, setComposerDraft] = useState(() => groupComposerDraftSnapshot(composerKey))
+
+  if (composerKeyRef.current !== composerKey) {
+    migrateGroupComposerDraft(composerKeyRef.current, composerKey)
+    composerKeyRef.current = composerKey
+  }
+
+  const updateComposerDraft = mutate => {
+    const next = updateGroupComposerDraft(composerKeyRef.current, mutate)
+    setComposerDraft(next)
+
+    return next
+  }
+
+  const draft = composerDraft.main || ''
+  const replyDrafts = composerDraft.replies || {}
+  const replyThread = composerDraft.activeReplyThread || null
+  const pendingImages = composerDraft.pendingAttachments || {}
+  const setDraft = value =>
+    updateComposerDraft(current => ({
+      ...current,
+      main: typeof value === 'function' ? value(current.main || '') : value
+    }))
+  const setReplyDrafts = value =>
+    updateComposerDraft(current => ({
+      ...current,
+      replies: typeof value === 'function' ? value(current.replies || {}) : value
+    }))
+  const setReplyThread = value =>
+    updateComposerDraft(current => ({
+      ...current,
+      activeReplyThread:
+        typeof value === 'function' ? value(current.activeReplyThread || null) : value
+    }))
+  const setPendingImages = value =>
+    updateComposerDraft(current => ({
+      ...current,
+      pendingAttachments:
+        typeof value === 'function' ? value(current.pendingAttachments || {}) : value
+    }))
   const [confirmDisband, setConfirmDisband] = useState(false)
   const [settingsOpen, setSettingsOpen] = useState(false)
   // Click-to-disambiguate: which log entry is showing its speaker's full
@@ -11318,12 +11442,9 @@ function GroupChatWorkspace({ group, members, onBack, visible = true }) {
   // `replyThread` is the thread whose reply box currently owns the composer
   // (null = the main composer, which STARTS a new thread).
   const [openThreads, setOpenThreads] = useState({})
-  const [replyThread, setReplyThread] = useState(null)
-  const [replyDrafts, setReplyDrafts] = useState({})
   // Pending image attachments per composer: `null` thread key = the main
   // composer, otherwise the reply box of that thread. Data URLs, already
   // downscaled — they ride the send into every responding member's session.
-  const [pendingImages, setPendingImages] = useState({})
 
   // Scroll anchoring (#89835): rooms used to open at scroll position 0 and
   // stay there while replies streamed in. Scroll the bottom sentinel into
@@ -11385,11 +11506,6 @@ function GroupChatWorkspace({ group, members, onBack, visible = true }) {
     setPendingImages(prev => ({ ...prev, [key]: [...(prev[key] || []), ...picked] }))
   }
 
-  const clearImages = thread => {
-    const key = thread ?? 'main'
-    setPendingImages(prev => ({ ...prev, [key]: [] }))
-  }
-
   const removeImage = (thread, index) => {
     const key = thread ?? 'main'
     setPendingImages(prev => ({ ...prev, [key]: (prev[key] || []).filter((_, i) => i !== index) }))
@@ -11579,8 +11695,12 @@ function GroupChatWorkspace({ group, members, onBack, visible = true }) {
       return
     }
 
-    setDraft('')
-    clearImages(null)
+    const before = groupComposerDraftSnapshot(composerKeyRef.current)
+    const cleared = updateComposerDraft(current => ({
+      ...current,
+      main: '',
+      pendingAttachments: { ...(current.pendingAttachments || {}), main: [] }
+    }))
     // Main composer = START A NEW THREAD with the whole group (Slack shape).
     // Full descriptors ride into the turn loop: remote members keep their
     // connection fields so their turns route to their own machines.
@@ -11588,6 +11708,12 @@ function GroupChatWorkspace({ group, members, onBack, visible = true }) {
 
     if (minted) {
       setOpenThreads(prev => ({ ...prev, [minted]: true }))
+    } else {
+      const restored = restoreGroupComposerDraft(composerKeyRef.current, cleared.revision, before)
+
+      if (restored) {
+        setComposerDraft(restored)
+      }
     }
   }
 
@@ -11599,12 +11725,25 @@ function GroupChatWorkspace({ group, members, onBack, visible = true }) {
       return
     }
 
-    setReplyDrafts(prev => ({ ...prev, [thread]: '' }))
-    clearImages(thread)
+    const before = groupComposerDraftSnapshot(composerKeyRef.current)
+    const cleared = updateComposerDraft(current => ({
+      ...current,
+      pendingAttachments: { ...(current.pendingAttachments || {}), [thread]: [] },
+      replies: { ...(current.replies || {}), [thread]: '' }
+    }))
     // Reply box = CONTINUE this thread; the member turns it triggers are
     // scoped to it.
-    sendToGroupChat(group, memberDescriptors(), text, thread, images)
-    setOpenThreads(prev => ({ ...prev, [thread]: true }))
+    const sent = sendToGroupChat(group, memberDescriptors(), text, thread, images)
+
+    if (sent) {
+      setOpenThreads(prev => ({ ...prev, [thread]: true }))
+    } else {
+      const restored = restoreGroupComposerDraft(composerKeyRef.current, cleared.revision, before)
+
+      if (restored) {
+        setComposerDraft(restored)
+      }
+    }
   }
 
   /** Pending-attachment chips + the picker for one composer (thread = null →
@@ -12040,6 +12179,7 @@ function GroupChatWorkspace({ group, members, onBack, visible = true }) {
         doneLabel: 'Disbanded',
         onClose: () => setConfirmDisband(false),
         onConfirm: async () => {
+          clearGroupComposerDraft(composerKeyRef.current)
           await disbandGroupChat(group, members)
           host.notify({ kind: 'success', message: `Disbanded “${group}”` })
         }
diff --git a/apps/desktop/src/plugins/hermes-bots/tests/group-chat-identity-edit.test.mjs b/apps/desktop/src/plugins/hermes-bots/tests/group-chat-identity-edit.test.mjs
index c96b4ada0e..775c4ae536 100644
--- a/apps/desktop/src/plugins/hermes-bots/tests/group-chat-identity-edit.test.mjs
+++ b/apps/desktop/src/plugins/hermes-bots/tests/group-chat-identity-edit.test.mjs
@@ -26,7 +26,9 @@ test('source contract: settings dialog edits name and picture after creation', (
 test('source contract: rename re-keys the room AND local memberships, keeps sessions', () => {
   // The room record moves wholesale under the new key (sessions included, so
   // members keep resuming their per-group sessions by stored sid).
-  assert.match(pluginSource, /const room = all\[oldName\]\s*\n\s*\n?\s*delete all\[oldName\]/)
+  assert.match(pluginSource, /const room = all\[oldName\][\s\S]{0,320}?delete all\[oldName\]/)
+  // Window-local composer drafts follow the immutable room identity too.
+  assert.match(pluginSource, /migrateGroupComposerDraft\(groupComposerDraftKey\(oldName, room\), groupComposerDraftKey\(next, room\)\)/)
   // Local members' canonical groups lists swap old → new via ui_meta.
   assert.match(pluginSource, /botGroups\(meta\)\.map\(g => \(g === oldName \? next : g\)\)/)
   // Collisions are rejected, not silently suffixed — rename is explicit intent.
diff --git a/apps/desktop/src/plugins/hermes-bots/tests/group-composer-drafts.test.mjs b/apps/desktop/src/plugins/hermes-bots/tests/group-composer-drafts.test.mjs
new file mode 100644
index 0000000000..6c4f0d5706
--- /dev/null
+++ b/apps/desktop/src/plugins/hermes-bots/tests/group-composer-drafts.test.mjs
@@ -0,0 +1,106 @@
+import assert from 'node:assert/strict'
+import { readFileSync } from 'node:fs'
+import test from 'node:test'
+import vm from 'node:vm'
+
+const source = readFileSync(new URL('../plugin.js', import.meta.url), 'utf8')
+
+function between(start, end) {
+  const from = source.indexOf(start)
+  const to = source.indexOf(end, from)
+
+  assert.notEqual(from, -1, `missing ${start}`)
+  assert.notEqual(to, -1, `missing ${end}`)
+
+  return source.slice(from, to)
+}
+
+function load() {
+  const context = { Map, Object }
+  const roomKey = between('function groupChatRoomKey(', '/** Lift any historical projection shape')
+  const drafts = between('const groupComposerDrafts = new Map()', 'function GroupChatWorkspace(')
+
+  vm.runInNewContext(
+    `${roomKey}\n${drafts}\nglobalThis.drafts = {
+      clearGroupComposerDraft,
+      groupComposerDraftKey,
+      groupComposerDraftSnapshot,
+      migrateGroupComposerDraft,
+      restoreGroupComposerDraft,
+      updateGroupComposerDraft
+    }`,
+    context
+  )
+
+  return context.drafts
+}
+
+test('workspace retirement and re-registration restore the exact room draft', () => {
+  const drafts = load()
+  const key = drafts.groupComposerDraftKey('Launch room', { roomId: 'room-1' })
+  const attachment = { data: 'data:image/png;base64,abc', kind: 'image', name: 'plan.png' }
+
+  drafts.updateGroupComposerDraft(key, state => ({
+    ...state,
+    activeReplyThread: 'thread-1',
+    main: 'main draft',
+    pendingAttachments: { main: [attachment], 'thread-1': [attachment] },
+    replies: { 'thread-1': 'reply draft' }
+  }))
+
+  // Dropping the component reference simulates pane retirement. A fresh
+  // registration reads the same module-scope, roomId-qualified snapshot.
+  const remounted = drafts.groupComposerDraftSnapshot(key)
+
+  assert.equal(remounted.main, 'main draft')
+  assert.equal(remounted.replies['thread-1'], 'reply draft')
+  assert.equal(remounted.activeReplyThread, 'thread-1')
+  assert.equal(remounted.pendingAttachments.main[0].name, 'plan.png')
+})
+
+test('legacy name-keyed drafts migrate when an immutable room id appears', () => {
+  const drafts = load()
+  const legacy = drafts.groupComposerDraftKey('Launch room', {})
+  const current = drafts.groupComposerDraftKey('Renamed room', { roomId: 'room-1' })
+
+  drafts.updateGroupComposerDraft(legacy, state => ({ ...state, main: 'keep me' }))
+  drafts.migrateGroupComposerDraft(legacy, current)
+
+  assert.equal(drafts.groupComposerDraftSnapshot(current).main, 'keep me')
+  assert.equal(drafts.groupComposerDraftSnapshot(legacy).main, '')
+})
+
+test('a failed send cannot overwrite text entered after the optimistic clear', () => {
+  const drafts = load()
+  const key = 'id:room-1'
+
+  drafts.updateGroupComposerDraft(key, state => ({ ...state, main: 'send this' }))
+  const before = drafts.groupComposerDraftSnapshot(key)
+  const cleared = drafts.updateGroupComposerDraft(key, state => ({ ...state, main: '' }))
+
+  drafts.updateGroupComposerDraft(key, state => ({ ...state, main: 'newer typing' }))
+
+  assert.equal(drafts.restoreGroupComposerDraft(key, cleared.revision, before), null)
+  assert.equal(drafts.groupComposerDraftSnapshot(key).main, 'newer typing')
+})
+
+test('disband removes only that room draft', () => {
+  const drafts = load()
+
+  drafts.updateGroupComposerDraft('id:a', state => ({ ...state, main: 'a' }))
+  drafts.updateGroupComposerDraft('id:b', state => ({ ...state, main: 'b' }))
+  drafts.clearGroupComposerDraft('id:a')
+
+  assert.equal(drafts.groupComposerDraftSnapshot('id:a').main, '')
+  assert.equal(drafts.groupComposerDraftSnapshot('id:b').main, 'b')
+})
+
+test('GroupChatWorkspace owns composer state through the room draft store', () => {
+  const workspace = between('function GroupChatWorkspace(', '/** Live closers for group-chat MAIN-window tabs')
+
+  assert.match(workspace, /groupComposerDraftKey\(group, room\)/)
+  assert.match(workspace, /restoreGroupComposerDraft\(composerKeyRef\.current, cleared\.revision, before\)/)
+  assert.match(workspace, /clearGroupComposerDraft\(composerKeyRef\.current\)/)
+  assert.doesNotMatch(workspace, /useState\(''\).*?draft/)
+  assert.doesNotMatch(workspace, /useState\(\{\}\).*?replyDrafts/)
+})