diff --git a/internal/agent/confirmation_handler.go b/internal/agent/confirmation_handler.go
index da2d583de3ff9a637a1d5c9e9f5fdfc54d5ca597..ceb5172ea679579acffbba6fc5811ab157414376 100644
--- a/internal/agent/confirmation_handler.go
+++ b/internal/agent/confirmation_handler.go
@@ -108,8 +108,11 @@ func (h *AsyncConfirmationHandler) AddSubAgentTool(toolName string) {
 
 // generateID generates a unique request ID
 func (h *AsyncConfirmationHandler) generateID() string {
+	h.mu.Lock()
 	h.nextID++
-	return fmt.Sprintf("confirm-%d-%d", time.Now().UnixNano(), h.nextID)
+	nextID := h.nextID
+	h.mu.Unlock()
+	return fmt.Sprintf("confirm-%d-%d", time.Now().UnixNano(), nextID)
 }
 
 // RequestConfirmation requests user confirmation for a tool call
@@ -623,4 +626,3 @@ func extractToolContent(toolCall *tools.ToolCall) string {
 	}
 	return ""
 }
-
diff --git a/internal/agent/confirmation_handler_id_test.go b/internal/agent/confirmation_handler_id_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..e1639640bb7ec12434c015e33c335b8bb6f8d5e3
--- /dev/null
+++ b/internal/agent/confirmation_handler_id_test.go
@@ -0,0 +1,37 @@
+package agent
+
+import (
+	"sync"
+	"testing"
+)
+
+func TestGenerateIDConcurrent(t *testing.T) {
+	const count = 1000
+	handler := NewAsyncConfirmationHandler(nil)
+	ids := make(chan string, count)
+	var wg sync.WaitGroup
+
+	for range count {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			ids <- handler.generateID()
+		}()
+	}
+	wg.Wait()
+	close(ids)
+
+	seen := make(map[string]struct{}, count)
+	for id := range ids {
+		if _, exists := seen[id]; exists {
+			t.Fatalf("duplicate confirmation ID generated: %s", id)
+		}
+		seen[id] = struct{}{}
+	}
+	if len(seen) != count {
+		t.Fatalf("generated %d unique IDs, want %d", len(seen), count)
+	}
+	if handler.nextID != count {
+		t.Fatalf("nextID = %d, want %d", handler.nextID, count)
+	}
+}