diff --git a/src/ink/termio/osc.test.ts b/src/ink/termio/osc.test.ts
index e9fbaf2c..d7a9cfd4 100644
--- a/src/ink/termio/osc.test.ts
+++ b/src/ink/termio/osc.test.ts
@@ -3,6 +3,8 @@ import { afterEach, beforeEach, describe, expect, mock, test } from 'bun:test'
 const originalEnv = { ...process.env }
 const originalPlatform = process.platform
 
+const generateTempFilePathMock = mock(() => '/tmp/openclaude-clipboard.txt')
+
 const execFileNoThrowMock = mock(
   async () => ({ code: 0, stdout: '', stderr: '' }),
 )
@@ -11,13 +13,22 @@ mock.module('../../utils/execFileNoThrow.js', () => ({
   execFileNoThrow: execFileNoThrowMock,
 }))
 
+mock.module('../../utils/tempfile.js', () => ({
+  generateTempFilePath: generateTempFilePathMock,
+}))
+
 async function importFreshOscModule() {
   return import(`./osc.ts?ts=${Date.now()}-${Math.random()}`)
 }
 
+async function flushClipboardCopy(): Promise<void> {
+  await new Promise(resolve => setTimeout(resolve, 0))
+}
+
 describe('Windows clipboard fallback', () => {
   beforeEach(() => {
     execFileNoThrowMock.mockClear()
+    generateTempFilePathMock.mockClear()
     process.env = { ...originalEnv }
     delete process.env['SSH_CONNECTION']
     delete process.env['TMUX']
@@ -34,6 +45,7 @@ describe('Windows clipboard fallback', () => {
     const { setClipboard } = await importFreshOscModule()
 
     await setClipboard('Привет мир')
+    await flushClipboardCopy()
 
     expect(execFileNoThrowMock.mock.calls.some(([cmd]) => cmd === 'clip')).toBe(
       false,
@@ -43,16 +55,28 @@ describe('Windows clipboard fallback', () => {
     ).toBe(true)
   })
 
-  test('passes the original Unicode text to the Windows copy command', async () => {
+  test('passes Windows clipboard text through a UTF-8 temp file instead of stdin', async () => {
     const { setClipboard } = await importFreshOscModule()
 
     await setClipboard('Привет мир')
+    await flushClipboardCopy()
 
     const windowsCall = execFileNoThrowMock.mock.calls.find(
       ([cmd]) => cmd === 'powershell',
     )
 
-    expect(windowsCall?.[2]).toMatchObject({ input: 'Привет мир' })
+    expect(windowsCall?.[2]).toMatchObject({
+      stdin: 'ignore',
+    })
+    expect(windowsCall?.[2]).not.toMatchObject({ input: 'Привет мир' })
+    expect(windowsCall?.[2]).not.toMatchObject({
+      env: expect.objectContaining({
+        OPENCLAUDE_CLIPBOARD_TEXT_B64: expect.any(String),
+      }),
+    })
+    expect(windowsCall?.[1]).toContain(
+      "$text = [System.IO.File]::ReadAllText('/tmp/openclaude-clipboard.txt', [System.Text.Encoding]::UTF8); Set-Clipboard -Value $text",
+    )
   })
 })
 
diff --git a/src/ink/termio/osc.ts b/src/ink/termio/osc.ts
index 59905432..5732b481 100644
--- a/src/ink/termio/osc.ts
+++ b/src/ink/termio/osc.ts
@@ -3,8 +3,10 @@
  */
 
 import { Buffer } from 'buffer'
+import { unlink, writeFile } from 'node:fs/promises'
 import { env } from '../../utils/env.js'
 import { execFileNoThrow } from '../../utils/execFileNoThrow.js'
+import { generateTempFilePath } from '../../utils/tempfile.js'
 import { BEL, ESC, ESC_TYPE, SEP } from './ansi.js'
 import type { Action, Color, TabStatusAction } from './types.js'
 
@@ -211,18 +213,32 @@ function copyNative(text: string): void {
       return
     }
     case 'win32':
-      // PowerShell's Set-Clipboard preserves Unicode text more reliably than
-      // clip.exe, which can mangle non-ASCII text under some Windows locales.
-      void execFileNoThrow(
-        'powershell',
-        [
-          '-NoProfile',
-          '-NonInteractive',
-          '-Command',
-          '$text = [Console]::In.ReadToEnd(); Set-Clipboard -Value $text',
-        ],
-        opts,
-      )
+      // Avoid piping non-ASCII text through the Windows stdin/codepage
+      // boundary. Write UTF-8 text to a temp file and let PowerShell read it
+      // directly as UTF-8 before calling Set-Clipboard.
+      void (async () => {
+        const tempPath = generateTempFilePath('openclaude-clipboard', '.txt')
+        const escapedTempPath = tempPath.replace(/'/g, "''")
+        try {
+          await writeFile(tempPath, text, { encoding: 'utf8' })
+          await execFileNoThrow(
+            'powershell',
+            [
+              '-NoProfile',
+              '-NonInteractive',
+              '-Command',
+              `$text = [System.IO.File]::ReadAllText('${escapedTempPath}', [System.Text.Encoding]::UTF8); Set-Clipboard -Value $text`,
+            ],
+            {
+              useCwd: false,
+              timeout: opts.timeout,
+              stdin: 'ignore',
+            },
+          )
+        } finally {
+          await unlink(tempPath).catch(() => {})
+        }
+      })().catch(() => {})
       return
   }
 }