Function filterWhitespaceOnlyAssistantMessages

src/utils/messages.ts:4875–4919

(
  messages: Message[],
)

  messages: Message[],
): Message[]
export function filterWhitespaceOnlyAssistantMessages(
  messages: Message[],
): Message[] {
  let hasChanges = false

  const filtered = messages.filter(message => {
    if (message.type !== 'assistant') {
      return true
    }

    const content = message.message.content
    // Keep messages with empty arrays (handled elsewhere) or that have real content
    if (!Array.isArray(content) || content.length === 0) {
      return true
    }

    if (hasOnlyWhitespaceTextContent(content)) {
      hasChanges = true
      logEvent('tengu_filtered_whitespace_only_assistant', {
        messageUUID:
          message.uuid as AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS,
      })
      return false
    }

    return true
  })

  if (!hasChanges) {
    return messages
  }

  // Removing assistant messages may leave adjacent user messages that need
  // merging (the API requires alternating user/assistant roles).
  const merged: Message[] = []
  for (const message of filtered) {
    const prev = merged.at(-1)
    if (message.type === 'user' && prev?.type === 'user') {
      merged[merged.length - 1] = mergeUserMessages(prev, message) // lvalue
    } else {
      merged.push(message)
    }
  }
  return merged
}

/**
 * Ensure all non-final assistant messages have non-empty content.