diff --git a/src/main/daemon/post-ready-flush-gate.test.ts b/src/main/daemon/post-ready-flush-gate.test.ts
index 6614f3fe79b..49379a53bad 100644
--- a/src/main/daemon/post-ready-flush-gate.test.ts
+++ b/src/main/daemon/post-ready-flush-gate.test.ts
@@ -83,4 +83,15 @@ describe('PostReadyFlushGate', () => {
     vi.advanceTimersByTime(POST_READY_FLUSH_DELAY_MS * 2)
     expect(onFlush).not.toHaveBeenCalled()
   })
+
+  it('isPending is true throughout the gate window and false once flush fires', () => {
+    expect(gate.isPending).toBe(false)
+    gate.arm()
+    expect(gate.isPending).toBe(true)
+    gate.notifyData()
+    expect(gate.isPending).toBe(true)
+    vi.advanceTimersByTime(POST_READY_FLUSH_DELAY_MS)
+    expect(gate.isPending).toBe(false)
+    expect(onFlush).toHaveBeenCalledTimes(1)
+  })
 })
diff --git a/src/main/daemon/post-ready-flush-gate.ts b/src/main/daemon/post-ready-flush-gate.ts
index a78442bdf2b..2e15b184068 100644
--- a/src/main/daemon/post-ready-flush-gate.ts
+++ b/src/main/daemon/post-ready-flush-gate.ts
@@ -28,6 +28,12 @@ export class PostReadyFlushGate {
 
   constructor(private readonly onFlush: () => void) {}
 
+  /** True between arm() and the actual flush firing. Callers should treat
+   *  input as still-queued during this window to preserve ordering. */
+  get isPending(): boolean {
+    return this.awaitingPromptDraw || this.postDataTimer !== null || this.fallbackTimer !== null
+  }
+
   /** Arm the gate after observing the shell-ready marker. Starts the
    *  wall-clock fallback; the flush fires when the fallback elapses or when
    *  notifyData() observes a subsequent PTY data chunk. */
diff --git a/src/main/daemon/session.test.ts b/src/main/daemon/session.test.ts
index 1fc7307778b..5191f77fd6b 100644
--- a/src/main/daemon/session.test.ts
+++ b/src/main/daemon/session.test.ts
@@ -178,29 +178,25 @@ describe('Session', () => {
   })
 
   describe('shell readiness gating', () => {
-    it('buffers writes during pending state', () => {
-      createSession({ shellReadySupported: true })
-      expect(session.shellState).toBe('pending')
-
-      session.write('buffered input')
-      expect(subprocess.written).toEqual([])
-    })
-
     // Why: regression guard for "claude claude" double-echo. The marker fires
     // from precmd before readline switches the PTY into raw mode; flushing
     // then lets the kernel re-echo the command under the prompt. Detailed
-    // timing behavior is covered by post-ready-flush-gate.test.ts; here we
-    // just verify Session wires the gate in (no write on the raw marker).
-    it('defers flush past the shell-ready marker to avoid kernel ECHO duplication', () => {
+    // timing behavior is covered by post-ready-flush-gate.test.ts.
+    // Also checks writes that arrive during the gate window keep their order
+    // — the gate continues to queue even though shellState is already 'ready'.
+    it('defers flush past the shell-ready marker and preserves write order', () => {
       createSession({ shellReadySupported: true })
-      session.write('claude\n')
+      expect(session.shellState).toBe('pending')
+
+      session.write('first\n')
       subprocess.simulateData('\x1b]777;orca-shell-ready\x07')
       expect(session.shellState).toBe('ready' satisfies ShellReadyState)
+      session.write('second\n')
       expect(subprocess.written).toEqual([])
 
       subprocess.simulateData('\r\nuser@host $ ')
       vi.advanceTimersByTime(30)
-      expect(subprocess.written).toEqual(['claude\n'])
+      expect(subprocess.written).toEqual(['first\n', 'second\n'])
     })
 
     it('transitions to timed_out after 15 seconds', () => {
diff --git a/src/main/daemon/session.ts b/src/main/daemon/session.ts
index 7ed9bf17019..4c398f5a2e0 100644
--- a/src/main/daemon/session.ts
+++ b/src/main/daemon/session.ts
@@ -106,7 +106,11 @@ export class Session {
       return
     }
 
-    if (this._shellState === 'pending') {
+    // Why: during the post-ready flush gate window (shellState is already
+    // 'ready' but the queue hasn't flushed yet) we must keep queuing. Writing
+    // directly would let fresh input race ahead of the buffered startup
+    // command, changing execution order.
+    if (this._shellState === 'pending' || this.postReadyFlushGate.isPending) {
       this.preReadyStdinQueue.push(data)
       return
     }