Struct Compactor 

pub struct Compactor {
    pub threshold_chars: usize,
    pub keep_recent_n: usize,
}

Configuration for LLM-driven transcript compaction.

Fields

threshold_chars: usize

Character-count threshold above which compaction is triggered. Defaults to usize::MAX (disabled).

keep_recent_n: usize

Number of most-recent messages to keep verbatim during compaction.

Implementations

impl Compactor

pub fn new(threshold_chars: usize) -> Self

Create a new compactor with the given threshold and default keep_recent_n (8).

pub fn keep_recent_n(self, n: usize) -> Self

Set the number of recent messages to preserve verbatim.

pub fn estimate_chars(transcript: &[Message]) -> usize

Estimate the prompt character count of a transcript.

This is a rough proxy for token count. The agent uses this to decide whether compaction is needed before the next LLM call.

pub async fn apply_to_transcript( &self, provider: &dyn LlmProvider, transcript: &mut Vec<Message>, ) -> Result<Option<(usize, usize)>>

Apply compaction in-place to transcript, returning (removed, summary_chars).

Finds the correct split point (never splits inside a tool-call pair), calls compact() to get the summary message, splices the transcript, and returns how many messages were removed and the summary char count.

Returns None when the transcript is too short to compact (< keep_recent_n + 2 messages).

pub async fn compact( &self, provider: &dyn LlmProvider, transcript: &[Message], ) -> Result<Message>

Compact the transcript: summarize older messages into a single system message, keeping the last keep_recent_n messages verbatim.

Returns the summary Message that should replace the older portion. The caller is responsible for splicing it into the transcript.

Trait Implementations

impl Clone for Compactor

fn clone(&self) -> Compactor

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Compactor

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Compactor

fn default() -> Self

Returns the “default value” for a type.