Struct AppendOnlyContext 

pub struct AppendOnlyContext { /* private fields */ }

Append-only context manager for the agent loop.

Separates immutable message history from pending tool results so that the byte prefix sent to the LLM never changes between turns. This maximizes provider-side KV cache / prompt caching.

Implementations

impl AppendOnlyContext

pub fn new(messages: Vec<Message>) -> Self

Create a new append-only context from existing messages.

pub fn empty() -> Self

Create an empty append-only context.

pub fn append(&mut self, msg: Message)

Append a message to the immutable history.

pub fn queue_tool_result(&mut self, msg: Message)

Queue a tool result for the next LLM turn.

pub fn finalize_turn(&mut self)

Fold pending tool results into the immutable history. Called at turn boundaries (after the LLM responds, before the next turn).

pub fn replace_history(&mut self, new_history: Vec<Message>)

Replace the entire history (used after compaction replaces messages). Pending tool results are discarded since compaction already folded them.

pub fn build_messages(&self) -> Vec<Message>

Build the full message list for the LLM: history + pending tool results.

pub fn history(&self) -> &[Message]

Get a reference to the immutable history.

pub fn pending_results(&self) -> &[Message]

Get a reference to the pending tool results.

pub fn len(&self) -> usize

Get the total message count (history + pending).

pub fn is_empty(&self) -> bool

Returns true if no messages exist.

pub fn sync_from(&mut self, external: &[Message]) -> usize

Sync from an external message list, appending only new messages.

This is needed when external code (e.g. the agent state) has a different view of the message list. Only messages beyond the current history length are appended.

Returns the number of newly appended messages.

pub fn into_messages(self) -> Vec<Message>

Consume self and return the underlying history vec.

Trait Implementations

impl Clone for AppendOnlyContext

fn clone(&self) -> AppendOnlyContext

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for AppendOnlyContext

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

Formats the value using the given formatter.