Function aliasMatchesParentTier

src/utils/model/agent.ts:110–122

* Check if a bare family alias (opus/sonnet/haiku) matches the parent model's * tier. When it does, the subagent inherits the parent's exact model string * instead of resolving the alias to a provider default. * * Prevents surprising downgrades: a Vertex user on Opus 4.6 (via /model) who * spaw

(alias: string, parentModel: string)

 * since they carry semantics beyond "same tier as parent".
 */
function aliasMatchesParentTier(alias: string, parentModel: string): boolean {
  const canonical = getCanonicalName(parentModel)
  switch (alias.toLowerCase()) {
    case 'opus':
      return canonical.includes('opus')
    case 'sonnet':
      return canonical.includes('sonnet')
    case 'haiku':
      return canonical.includes('haiku')
    default:
      return false
  }
}

export function getAgentModelDisplay(model: string | undefined): string {
  // When model is omitted, getDefaultSubagentModel() returns 'inherit' at runtime