diff --git a/apps/desktop/src/app/chat/composer/empty-composer.test.ts b/apps/desktop/src/app/chat/composer/empty-composer.test.ts
new file mode 100644
index 00000000000..4e5146c174d
--- /dev/null
+++ b/apps/desktop/src/app/chat/composer/empty-composer.test.ts
@@ -0,0 +1,71 @@
+import { describe, expect, it } from 'vitest'
+
+import { composerPlainText, normalizeComposerEditorDom, RICH_INPUT_SLOT } from './rich-editor'
+
+function editor(): HTMLDivElement {
+  const el = document.createElement('div')
+
+  el.dataset.slot = RICH_INPUT_SLOT
+  el.contentEditable = 'true'
+  document.body.append(el)
+
+  return el
+}
+
+/** Whatever emptied it — Delete, cut, Chromium's own selection-delete — the
+ *  normalizer lands on the same DOM. */
+function emptied(): HTMLDivElement {
+  const el = editor()
+
+  el.append(document.createTextNode('hello'))
+  el.replaceChildren()
+  normalizeComposerEditorDom(el)
+
+  return el
+}
+
+describe('an emptied composer reads as empty', () => {
+  it('keeps the placeholder <br> so the contenteditable holds its height', () => {
+    // The scaffolding is deliberate: a childless contenteditable collapses to a
+    // sliver in Chromium. It just must not read as content.
+    expect(emptied().innerHTML).toBe('<br>')
+  })
+
+  it('reads that editor as empty, not as a newline', () => {
+    expect(composerPlainText(emptied())).toBe('')
+  })
+
+  it('reads a truly childless editor as empty', () => {
+    expect(composerPlainText(editor())).toBe('')
+  })
+
+  it('still reads a real Shift+Enter line break as a newline', () => {
+    const el = editor()
+
+    el.append(document.createTextNode('one'), document.createElement('br'), document.createTextNode('two'))
+
+    expect(composerPlainText(el)).toBe('one\ntwo')
+  })
+
+  it('still reads a trailing break after text as a newline', () => {
+    const el = editor()
+
+    el.append(document.createTextNode('one'), document.createElement('br'))
+
+    expect(composerPlainText(el)).toBe('one\n')
+  })
+
+  it('only treats the EDITOR\u2019s lone <br> as scaffolding, not a nested one', () => {
+    // A lone <br> inside some other element is a real line break; the exemption
+    // is scoped to the editor root by its slot marker. (The block wrapper adds
+    // its own trailing newline — unchanged behavior, asserted so the exemption
+    // can't quietly widen to nested nodes.)
+    const el = editor()
+    const inner = document.createElement('div')
+
+    inner.append(document.createElement('br'))
+    el.append(document.createTextNode('one'), inner)
+
+    expect(composerPlainText(el)).toBe('one\n\n')
+  })
+})
diff --git a/apps/desktop/src/app/chat/composer/hooks/use-composer-draft.ts b/apps/desktop/src/app/chat/composer/hooks/use-composer-draft.ts
index 82464ffd5d4..b5bf87dc466 100644
--- a/apps/desktop/src/app/chat/composer/hooks/use-composer-draft.ts
+++ b/apps/desktop/src/app/chat/composer/hooks/use-composer-draft.ts
@@ -2,6 +2,7 @@ import { useAui, useAuiState, useComposerRuntime } from '@assistant-ui/react'
 import { type RefObject, useCallback, useEffect, useLayoutEffect, useRef, useState } from 'react'
 
 import { SLASH_COMMAND_RE } from '@/lib/chat-runtime'
+import { sanitizeComposerInput } from '@/lib/composer-input-sanitize'
 import { type ComposerAttachment, stashSessionDraft, takeSessionDraft } from '@/store/composer'
 import { isBrowsingHistory } from '@/store/composer-input-history'
 
@@ -21,7 +22,13 @@ import {
   releaseActiveComposer
 } from '../focus'
 import { type InlineRefInput, insertInlineRefsIntoEditor } from '../inline-refs'
-import { composerPlainText, placeCaretEnd, REF_RE, renderComposerContents } from '../rich-editor'
+import {
+  composerPlainText,
+  normalizeComposerEditorDom,
+  placeCaretEnd,
+  REF_RE,
+  renderComposerContents
+} from '../rich-editor'
 import { useComposerScope } from '../scope'
 import type { ChatBarProps } from '../types'
 
@@ -237,7 +244,13 @@ export function useComposerDraft({
       return draftRef.current
     }
 
-    const text = composerPlainText(editor)
+    // Same normalize-then-sanitize the rAF flush does. An emptied editor still
+    // holds the placeholder <br> that keeps the contenteditable from collapsing
+    // to a sliver, and that serializes as "\n" — so an editor the user just
+    // cleared would otherwise stash a one-newline draft and come back non-empty.
+    normalizeComposerEditorDom(editor)
+
+    const text = sanitizeComposerInput(composerPlainText(editor))
 
     if (text !== draftRef.current) {
       draftRef.current = text
diff --git a/apps/desktop/src/app/chat/composer/rich-editor.ts b/apps/desktop/src/app/chat/composer/rich-editor.ts
index 6285a4dcfd0..3b3ba5db2fa 100644
--- a/apps/desktop/src/app/chat/composer/rich-editor.ts
+++ b/apps/desktop/src/app/chat/composer/rich-editor.ts
@@ -480,6 +480,15 @@ export function composerPlainText(node: Node): string {
     return el.dataset.refText
   }
 
+  // An editor holding nothing but the placeholder <br> is EMPTY. That <br> is
+  // scaffolding normalizeComposerEditorDom adds so the contenteditable keeps
+  // its height — not a line the user typed. Reading it as "\n" is how a
+  // just-cleared composer stayed non-empty: the newline got stashed as the
+  // session's draft and painted back on return.
+  if (el.dataset.slot === RICH_INPUT_SLOT && el.childNodes.length === 1 && el.firstChild?.nodeName === 'BR') {
+    return ''
+  }
+
   if (el.tagName === 'BR') {
     return '\n'
   }