`class Compactor`

Context compaction service. When the conversation grows past configurable thresholds, older messages are summarized into a condensed form and the original messages are dropped, keeping the context window manageable.

Definitions

`def should_compact?(messages, usage: nil)`

Check whether compaction should run based on current context state.

Implementation

def should_compact?(messages, usage: nil)
  return true if messages.size > @config[:message_threshold]
  return true if usage && (usage[:total] || 0) > @config[:token_threshold]
  false
end

`def compact(messages)`

Compact the message history by summarizing older messages.

Returns [summary_message, kept_messages] — the caller rebuilds the context from these.

Implementation

def compact(messages)
  total = messages.size
  keep_count = [@config[:retention_window], total].min
  return nil if total <= keep_count

  old_messages = messages[0...(total - keep_count)]
  recent_messages = messages[(total - keep_count)..]

  summary_text = summarize(old_messages)

  [summary_text, recent_messages]
end