Add inline thinking mode helper

packages/cli/src/ui/utils/inlineThinkingMode.ts

@@ -0,0 +1,29 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import type { LoadedSettings } from '../../config/settings.js';
+
+export type InlineThinkingMode = 'off' | 'summary' | 'full';
+
+export function getInlineThinkingMode(
+  settings: LoadedSettings,
+): InlineThinkingMode {
+  const ui = settings.merged.ui;
+
+  if (ui?.showInlineThinkingFull) {
+    return 'full';
+  }
+
+  if (ui?.showInlineThinkingSummary) {
+    return 'summary';
+  }
+
+  if (ui?.showInlineThinking) {
+    return 'full';
+  }
+
+  return 'off';
+}