Behaviour for compacting a session's conversation history.

Long-running agents accumulate messages that grow past the model's context window. A compactor receives the current message list and returns a shorter one — by dropping old turns, eliding large tool results, or replacing a prefix with a summary.

Compactors are pluggable just like Condukt.SessionStore. Pass one to start_link/1 and Condukt will apply it after each completed turn.

MyApp.Agent.start_link(
  compactor: Condukt.Compactor.Sliding
)

MyApp.Agent.start_link(
  compactor: {Condukt.Compactor.Sliding, keep: 30}
)

Compaction can also be triggered manually with Condukt.compact/1.

Built-in compactors

• Condukt.Compactor.Sliding — keeps the most recent N messages.
• Condukt.Compactor.ToolResultPrune — replaces old tool result payloads with a placeholder, preserving the surrounding reasoning structure.

Implementing a compactor

defmodule MyApp.MyCompactor do
  @behaviour Condukt.Compactor

  @impl true
  def compact(messages, _opts) do
    {:ok, Enum.take(messages, -10)}
  end
end

Telemetry

Each compaction emits a [:condukt, :compact, :stop] event with measurements %{duration, before, after} and metadata %{agent}.