Function getContextWindowForModel

src/utils/context.ts:51–98

(
  model: string,
  betas?: string[],
)

}

export function getContextWindowForModel(
  model: string,
  betas?: string[],
): number {
  // Allow override via environment variable (ant-only)
  // This takes precedence over all other context window resolution, including 1M detection,
  // so users can cap the effective context window for local decisions (auto-compact, etc.)
  // while still using a 1M-capable endpoint.
  if (
    process.env.USER_TYPE === 'ant' &&
    process.env.CLAUDE_CODE_MAX_CONTEXT_TOKENS
  ) {
    const override = parseInt(process.env.CLAUDE_CODE_MAX_CONTEXT_TOKENS, 10)
    if (!isNaN(override) && override > 0) {
      return override
    }
  }

  // [1m] suffix — explicit client-side opt-in, respected over all detection
  if (has1mContext(model)) {
    return 1_000_000
  }

  const cap = getModelCapability(model)
  if (cap?.max_input_tokens && cap.max_input_tokens >= 100_000) {
    if (
      cap.max_input_tokens > MODEL_CONTEXT_WINDOW_DEFAULT &&
      is1mContextDisabled()
    ) {
      return MODEL_CONTEXT_WINDOW_DEFAULT
    }
    return cap.max_input_tokens
  }

  if (betas?.includes(CONTEXT_1M_BETA_HEADER) && modelSupports1M(model)) {
    return 1_000_000
  }
  if (getSonnet1mExpTreatmentEnabled(model)) {
    return 1_000_000
  }
  if (process.env.USER_TYPE === 'ant') {
    const antModel = resolveAntModel(model)
    if (antModel?.contextWindow) {
      return antModel.contextWindow
    }
  }
  return MODEL_CONTEXT_WINDOW_DEFAULT
}

export function getSonnet1mExpTreatmentEnabled(model: string): boolean {
  if (is1mContextDisabled()) {