Trait BlockCompactionStrategy 

pub trait BlockCompactionStrategy: Send + Sync {
    // Required methods
    fn keep_first(
        &self,
        record: &LoopRecord,
        turn_map: &TurnMap,
        config: &CompactionConfig,
    ) -> Option<TurnRange>;
    fn keep_recent(
        &self,
        record: &LoopRecord,
        turn_map: &TurnMap,
        config: &CompactionConfig,
    ) -> Option<CompactedSection>;
    fn keep_compacted(
        &self,
        record: &LoopRecord,
        turn_map: &TurnMap,
        config: &CompactionConfig,
        is_most_recent: bool,
    ) -> Option<CompactedSection>;

    // Provided method
    fn compact(
        &self,
        record: &LoopRecord,
        config: &CompactionConfig,
        is_most_recent: bool,
    ) -> CompactionBlock { ... }
}

Strategy for creating non-destructive CompactionBlock overlays.

Three methods produce the three sections of a CompactionBlock:

• keep_first: turns kept verbatim from the start
• keep_recent: recent turns with truncated tool outputs
• keep_compacted: fully summarised section

The default compact() method assembles them. Override individual methods to customise specific sections (e.g. LLM-based summarisation for keep_compacted).

Required Methods

fn keep_first( &self, record: &LoopRecord, turn_map: &TurnMap, config: &CompactionConfig, ) -> Option<TurnRange>

Determine the keep_first section: turns kept verbatim from the start. Only called for the most recent loop.

fn keep_recent( &self, record: &LoopRecord, turn_map: &TurnMap, config: &CompactionConfig, ) -> Option<CompactedSection>

Create the keep_recent section: recent turns with truncated tool outputs. Only called for the most recent loop.

fn keep_compacted( &self, record: &LoopRecord, turn_map: &TurnMap, config: &CompactionConfig, is_most_recent: bool, ) -> Option<CompactedSection>

Create the keep_compacted section: fully summarised turns. For most recent loop: summarises the middle (between keep_first and keep_recent). For older loops: summarises the entire loop.

Implementations should aim to summarise ALL turns in the range within config.max_summary_tokens — e.g. shorter per-turn summaries or an LLM-generated holistic digest. The token budget is for the total output, not a per-turn limit.

Provided Methods

fn compact( &self, record: &LoopRecord, config: &CompactionConfig, is_most_recent: bool, ) -> CompactionBlock

Assemble a CompactionBlock from the three sections. Default implementation calls the three methods above.

Implementors

impl BlockCompactionStrategy for DefaultBlockCompaction