Function checkAndCompress

packages/node-runtime/src/ai/compression/compressor.ts:65–186

(
  aiChatId: string,
  config: CompressionConfig,
  systemPrompt: string,
  llmAdapter: CompressionLlmAdapter,
  convManager: AIChatManager,
  logger: CompressionLogger = defaultLogger
)

}

export async function checkAndCompress(
  aiChatId: string,
  config: CompressionConfig,
  systemPrompt: string,
  llmAdapter: CompressionLlmAdapter,
  convManager: AIChatManager,
  logger: CompressionLogger = defaultLogger
): Promise<CompressionResult> {
  if (!config.enabled) {
    return { compressed: false, reason: 'skipped_disabled' }
  }

  try {
    const contextWindow = llmAdapter.contextWindow || DEFAULT_CONTEXT_WINDOW
    const thresholdTokens = Math.floor(contextWindow * (config.tokenThresholdPercent / 100) * 0.95)

    const summary = convManager.getLatestSummary(aiChatId)

    let messages: Array<{ role: AIMessageRole; content: string; timestamp: number; contentBlocks?: ContentBlock[] }>
    if (summary) {
      const metaBlock = summary.contentBlocks?.find(
        (b): b is Extract<ContentBlock, { type: 'summary_meta' }> => b.type === 'summary_meta'
      )
      const boundary = metaBlock?.bufferBoundaryTimestamp ?? summary.timestamp
      messages = convManager.getMessagesAfterSummary(aiChatId, boundary - 1)
    } else {
      messages = convManager.getAllUserAssistantMessages(aiChatId)
    }

    const historyForTokenCount: Array<{ role: string; content: string }> = []
    if (summary) {
      historyForTokenCount.push({ role: 'assistant', content: summary.content })
    }
    for (const msg of messages) {
      historyForTokenCount.push({ role: msg.role, content: msg.content })
      // Persisted tool results are replayed as toolCall/toolResult pairs each
      // turn (see agent/history.ts), so they occupy real context and must be counted.
      for (const toolText of replayedToolResultTexts(msg.contentBlocks)) {
        historyForTokenCount.push({ role: 'tool', content: toolText })
      }
    }

    const currentTokens = countMessagesTokens(historyForTokenCount, systemPrompt)

    logger.info('Compression', `Token check: ${currentTokens} / ${thresholdTokens} (${contextWindow} window)`, {
      aiChatId,
      messageCount: messages.length,
      hasSummary: !!summary,
    })

    if (currentTokens < thresholdTokens) {
      return { compressed: false, reason: 'skipped_below_threshold', tokensBefore: currentTokens }
    }

    const bufferTokenBudget = Math.floor(contextWindow * (config.bufferSizePercent / 100))
    const { bufferMessages, messagesToCompress } = splitMessagesForCompression(messages, bufferTokenBudget)

    const MIN_MESSAGES_TO_COMPRESS = 3