Function getErrorMessageIfRefusal

src/services/api/errors.ts:1182–1205

(
  stopReason: BetaStopReason | null,
  model: string,
)

}

export function getErrorMessageIfRefusal(
  stopReason: BetaStopReason | null,
  model: string,
): AssistantMessage | undefined {
  if (stopReason !== 'refusal') {
    return
  }

  logEvent('tengu_refusal_api_response', {})

  const baseMessage = getIsNonInteractiveSession()
    ? `${API_ERROR_MESSAGE_PREFIX}: Claude Code is unable to respond to this request, which appears to violate our Usage Policy (https://www.anthropic.com/legal/aup). Try rephrasing the request or attempting a different approach.`
    : `${API_ERROR_MESSAGE_PREFIX}: Claude Code is unable to respond to this request, which appears to violate our Usage Policy (https://www.anthropic.com/legal/aup). Please double press esc to edit your last message or start a new session for Claude Code to assist with a different task.`

  const modelSuggestion =
    model !== 'claude-sonnet-4-20250514'
      ? ' If you are seeing this refusal repeatedly, try running /model claude-sonnet-4-20250514 to switch models.'
      : ''

  return createAssistantAPIErrorMessage({
    content: baseMessage + modelSuggestion,
    error: 'invalid_request',
  })
}