# `Condukt.Compactor`
[🔗](https://github.com/tuist/condukt/blob/0.16.5/lib/condukt/compactor.ex#L1)

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}`.

# `compact`

```elixir
@callback compact(
  [Condukt.Message.t()],
  keyword()
) :: {:ok, [Condukt.Message.t()]} | {:error, term()}
```

# `compact`

Dispatches `compact/2` to the configured compactor module or `{module, opts}`
tuple. Default options are merged underneath the tuple's options.

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*Consult [api-reference.md](api-reference.md) for complete listing*