diff --git a/src/main/runtime/agent-prompt-submission-runtime.test.ts b/src/main/runtime/agent-prompt-submission-runtime.test.ts
index 8b996b80874..711e887b5c5 100644
--- a/src/main/runtime/agent-prompt-submission-runtime.test.ts
+++ b/src/main/runtime/agent-prompt-submission-runtime.test.ts
@@ -676,8 +676,10 @@ describe('agent prompt submission runtime', () => {
     })
     const rejected = expect(submission).rejects.toThrow('request_aborted')
 
-    // Why: the settle delay is platform-dependent (1_500 on Windows); a hardcoded 500 aborts before the Enter there.
+    // Why: the submit delay is 1_500 on Windows (ConPTY); a hardcoded 500 aborts before the Enter there.
     await vi.advanceTimersByTimeAsync(AGENT_PROMPT_SUBMIT_DELAY_MS)
+    // Why: pin the phase boundary so drift fails here instead of as an empty post-abort array.
+    expect(writes.filter((data) => data === '\r')).toHaveLength(1)
     controller.abort()
     await vi.runAllTimersAsync()
 
diff --git a/src/main/runtime/agent-prompt-submission-windows-submit-delay.test.ts b/src/main/runtime/agent-prompt-submission-windows-submit-delay.test.ts
new file mode 100644
index 00000000000..fdb90700de1
--- /dev/null
+++ b/src/main/runtime/agent-prompt-submission-windows-submit-delay.test.ts
@@ -0,0 +1,100 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import type * as AgentPromptInjection from '../../shared/agent-prompt-injection'
+import { OrcaRuntimeService } from './orca-runtime'
+import { makeStore } from './runtime-rpc-worktree-store-fixtures'
+
+// Why: vi.mock factories are hoisted above module-scope consts, so the delay must be hoisted too.
+const { WINDOWS_SUBMIT_DELAY_MS } = vi.hoisted(() => ({ WINDOWS_SUBMIT_DELAY_MS: 1_500 }))
+const WORKTREE_PATH = '/tmp/worktree-a'
+
+// Why: AGENT_PROMPT_SUBMIT_DELAY_MS is frozen from process.platform at import, so the 1_500 ConPTY
+// path is otherwise unreachable on the Linux/macOS lanes that run this suite.
+vi.mock('../../shared/agent-prompt-injection', async (importOriginal) => ({
+  ...(await importOriginal<typeof AgentPromptInjection>()),
+  AGENT_PROMPT_SUBMIT_DELAY_MS: WINDOWS_SUBMIT_DELAY_MS
+}))
+
+vi.mock('../git/worktree', () => ({
+  listWorktrees: vi.fn().mockResolvedValue([
+    {
+      path: '/tmp/worktree-a',
+      head: 'abc',
+      branch: 'feature/prompt-verification',
+      isBare: false,
+      isMainWorktree: false
+    }
+  ]),
+  listWorktreesStrict: vi.fn().mockResolvedValue([
+    {
+      path: '/tmp/worktree-a',
+      head: 'abc',
+      branch: 'feature/prompt-verification',
+      isBare: false,
+      isMainWorktree: false
+    }
+  ])
+}))
+
+// Why: 'aider' is not a settlement agent, so submission takes the fixed-delay branch under test.
+async function createPromptRuntime(): Promise<{
+  runtime: OrcaRuntimeService
+  handle: string
+  writes: string[]
+}> {
+  const runtime = new OrcaRuntimeService(makeStore() as never)
+  const writes: string[] = []
+  runtime.setPtyController({
+    spawn: vi.fn().mockResolvedValue({ id: 'pty-prompt' }),
+    write: (_ptyId, data) => {
+      writes.push(data)
+      return true
+    },
+    kill: () => true,
+    getForegroundProcess: async () => null
+  })
+  const terminal = await runtime.createTerminal(`path:${WORKTREE_PATH}`, {
+    launchAgent: 'aider'
+  })
+  return { runtime, handle: terminal.handle, writes }
+}
+
+function countSubmits(writes: readonly string[]): number {
+  return writes.filter((data) => data === '\r').length
+}
+
+describe('agent prompt submission at the Windows submit delay', () => {
+  afterEach(() => vi.useRealTimers())
+
+  it('holds Enter until the full platform delay elapses', async () => {
+    vi.useFakeTimers()
+    const { runtime, handle, writes } = await createPromptRuntime()
+    const submission = runtime.sendTerminalAgentPrompt(handle, 'review this')
+    const stalled = expect(submission).rejects.toThrow('agent_prompt_stalled')
+
+    await vi.advanceTimersByTimeAsync(WINDOWS_SUBMIT_DELAY_MS - 1)
+    expect(countSubmits(writes)).toBe(0)
+    await vi.advanceTimersByTimeAsync(1)
+    expect(countSubmits(writes)).toBe(1)
+
+    await vi.runAllTimersAsync()
+    await stalled
+  })
+
+  it('does not send another Enter after cancellation during verification', async () => {
+    vi.useFakeTimers()
+    const controller = new AbortController()
+    const { runtime, handle, writes } = await createPromptRuntime()
+    const submission = runtime.sendTerminalAgentPrompt(handle, 'review this', {
+      signal: controller.signal
+    })
+    const rejected = expect(submission).rejects.toThrow('request_aborted')
+
+    await vi.advanceTimersByTimeAsync(WINDOWS_SUBMIT_DELAY_MS)
+    expect(countSubmits(writes)).toBe(1)
+    controller.abort()
+    await vi.runAllTimersAsync()
+
+    await rejected
+    expect(countSubmits(writes)).toBe(1)
+  })
+})