Function parseUserSpecifiedModel

source code/utils/model/model.ts:447–508

(
  modelInput: ModelName | ModelAlias,
)

 * @param modelInput The model alias or name provided by the user.
 */
export function parseUserSpecifiedModel(
  modelInput: ModelName | ModelAlias,
): ModelName {
  const modelInputTrimmed = modelInput.trim()
  const normalizedModel = modelInputTrimmed.toLowerCase()

  const has1mTag = has1mContext(normalizedModel)
  const modelString = has1mTag
    ? normalizedModel.replace(/\[1m]$/i, '').trim()
    : normalizedModel

  if (isModelAlias(modelString)) {
    switch (modelString) {
      case 'opusplan':
        return getDefaultSonnetModel() + (has1mTag ? '[1m]' : '') // Sonnet is default, Opus in plan mode
      case 'sonnet':
        return getDefaultSonnetModel() + (has1mTag ? '[1m]' : '')
      case 'haiku':
        return getDefaultHaikuModel() + (has1mTag ? '[1m]' : '')
      case 'opus':
        return getDefaultOpusModel() + (has1mTag ? '[1m]' : '')
      case 'best':
        return getBestModel()
      default:
    }
  }

  // Opus 4/4.1 are no longer available on the first-party API (same as
  // Claude.ai) — silently remap to the current Opus default. The 'opus'
  // alias already resolves to 4.6, so the only users on these explicit
  // strings pinned them in settings/env/--model/SDK before 4.5 launched.
  // 3P providers may not yet have 4.6 capacity, so pass through unchanged.
  if (
    getAPIProvider() === 'firstParty' &&
    isLegacyOpusFirstParty(modelString) &&
    isLegacyModelRemapEnabled()
  ) {
    return getDefaultOpusModel() + (has1mTag ? '[1m]' : '')
  }

  if (process.env.USER_TYPE === 'ant') {
    const has1mAntTag = has1mContext(normalizedModel)
    const baseAntModel = normalizedModel.replace(/\[1m]$/i, '').trim()

    const antModel = resolveAntModel(baseAntModel)
    if (antModel) {
      const suffix = has1mAntTag ? '[1m]' : ''
      return antModel.model + suffix
    }

    // Fall through to the alias string if we cannot load the config. The API calls
    // will fail with this string, but we should hear about it through feedback and
    // can tell the user to restart/wait for flag cache refresh to get the latest values.
  }

  // Preserve original case for custom model names (e.g., Azure Foundry deployment IDs)
  // Only strip [1m] suffix if present, maintaining case of the base model
  if (has1mTag) {