Function enforceThinkingPolicy

src/common/utils/thinking/policy.ts:241–276

(
  modelString: string,
  requested: ThinkingLevel,
  minimum?: ThinkingLevel | null
)

 * preserves the legacy capability-only behavior.
 */
export function enforceThinkingPolicy(
  modelString: string,
  requested: ThinkingLevel,
  minimum?: ThinkingLevel | null
): ThinkingLevel {
  const allowed = getAvailableThinkingLevels(modelString, minimum);

  if (allowed.includes(requested)) {
    return requested;
  }

  const orderedAllowed = [...allowed].sort(
    (left, right) => THINKING_LEVELS.indexOf(left) - THINKING_LEVELS.indexOf(right)
  );
  const minAllowed = orderedAllowed[0] ?? "off";
  const maxAllowed = orderedAllowed[orderedAllowed.length - 1] ?? minAllowed;
  const requestedIndex = THINKING_LEVELS.indexOf(requested);

  if (requestedIndex <= THINKING_LEVELS.indexOf(minAllowed)) {
    return minAllowed;
  }

  if (requestedIndex >= THINKING_LEVELS.indexOf(maxAllowed)) {
    return maxAllowed;
  }

  const closest = orderedAllowed.reduce((nearest, level) => {
    const nearestIndex = THINKING_LEVELS.indexOf(nearest);
    const levelIndex = THINKING_LEVELS.indexOf(level);
    return Math.abs(levelIndex - requestedIndex) < Math.abs(nearestIndex - requestedIndex)
      ? level
      : nearest;
  }, minAllowed);

  return closest;
}
/**
 * Resolve a parsed thinking input to a concrete ThinkingLevel for a given model.
 *