diff --git a/src/renderer/src/components/NewWorkspaceComposerCard.test.tsx b/src/renderer/src/components/NewWorkspaceComposerCard.test.tsx
index 16a7b82be..33fc74098 100644
--- a/src/renderer/src/components/NewWorkspaceComposerCard.test.tsx
+++ b/src/renderer/src/components/NewWorkspaceComposerCard.test.tsx
@@ -871,3 +871,42 @@ describe('NewWorkspaceComposerCard folder task source mode', () => {
     expect(recipeChanges).toEqual([null])
   })
 })
+
+describe('NewWorkspaceComposerCard note sizing', () => {
+  // Sizing is layout-driven (field-sizing) rather than a JS measure pass, and happy-dom
+  // has no layout engine, so these assert the class contract that produces the growth.
+  afterEach(() => {
+    act(() => current?.root.unmount())
+    current?.container.remove()
+    current = null
+  })
+
+  function findNoteTextarea(container: HTMLElement): HTMLTextAreaElement {
+    const label = [...container.querySelectorAll('label')].find(
+      (candidate) => candidate.textContent?.trim() === 'Note'
+    )
+    const textarea = label?.parentElement?.querySelector('textarea')
+    expect(textarea).toBeTruthy()
+    return textarea as HTMLTextAreaElement
+  }
+
+  it('sizes from the note value, so a PR prefill written straight to state still shows in full', () => {
+    // #10575: the prefill never fires an input event, so nothing but the value can drive height.
+    current = renderCard({
+      advancedOpen: true,
+      note: `PR #10575 — ${'a note title long enough to wrap over several lines '.repeat(3)}`
+    })
+
+    expect(findNoteTextarea(current.container).className).toContain('[field-sizing:content]')
+  })
+
+  it('keeps a note past the height cap readable instead of clipping it', () => {
+    current = renderCard({ advancedOpen: true, note: 'a'.repeat(4000) })
+
+    const { className } = findNoteTextarea(current.container)
+    expect(className).toContain('max-h-40')
+    expect(className).toContain('overflow-y-auto')
+    expect(className).toContain('scrollbar-sleek')
+    expect(className).not.toContain('overflow-hidden')
+  })
+})
diff --git a/src/renderer/src/components/NewWorkspaceComposerCard.tsx b/src/renderer/src/components/NewWorkspaceComposerCard.tsx
index f01350a6d..478494916 100644
--- a/src/renderer/src/components/NewWorkspaceComposerCard.tsx
+++ b/src/renderer/src/components/NewWorkspaceComposerCard.tsx
@@ -1001,18 +1001,15 @@ export default function NewWorkspaceComposerCard({
                   value={note}
                   onChange={(event) => onNoteChange(event.target.value)}
                   onPaste={handleNotePaste}
-                  onInput={(event) => {
-                    // Why: reset then size to content so short notes stay compact and long ones grow without a scrollbar until max-h clamps.
-                    const ta = event.currentTarget
-                    ta.style.height = 'auto'
-                    ta.style.height = `${ta.scrollHeight}px`
-                  }}
                   placeholder={translate(
                     'auto.components.NewWorkspaceComposerCard.090cfedeb4',
                     'Write a note'
                   )}
                   rows={1}
-                  className="w-full min-w-0 resize-none overflow-hidden rounded-md border border-input bg-transparent px-3 py-1.5 text-sm shadow-xs transition-[color,box-shadow] outline-none placeholder:text-muted-foreground focus-visible:border-ring focus-visible:ring-[3px] focus-visible:ring-ring/50 max-h-40"
+                  // Why (#10575): field-sizing:content grows the note with its value, so a PR/MR
+                  // prefill written straight to state sizes like typed text — an onInput measure
+                  // pass never saw it. Past the max-h clamp the sleek scrollbar keeps it readable.
+                  className="w-full min-w-0 resize-none overflow-y-auto scrollbar-sleek rounded-md border border-input bg-transparent px-3 py-1.5 text-sm shadow-xs transition-[color,box-shadow] outline-none placeholder:text-muted-foreground focus-visible:border-ring focus-visible:ring-[3px] focus-visible:ring-ring/50 [field-sizing:content] max-h-40"
                 />
               </div>