Struct ConversationHistory 

pub struct ConversationHistory { /* private fields */ }

Manages an ordered conversation history with role validation and token-budget-aware truncation.

Implementations

impl ConversationHistory

pub fn new() -> Self

Create a new empty conversation history.

pub fn len(&self) -> usize

Number of messages in the history.

pub fn is_empty(&self) -> bool

Whether the history is empty.

pub fn messages(&self) -> &[ChatMessage]

Access the messages.

pub fn push(&mut self, message: ChatMessage) -> Result<(), RoleValidationError>

Append a message with role alternation validation.

Rules:

• First message can be System, User, or Tool.
• System is only allowed as the first message.
• User must follow Assistant or be first.
• Assistant must follow User or Tool.
• Tool must follow Assistant or another Tool (parallel tool results).

pub fn token_count(&self) -> u32

Estimate the total token count of all messages.

pub fn truncate_to_budget(&mut self, budget: &TokenBudget, needed: u32) -> usize

Remove the oldest non-system messages until the token budget has enough remaining capacity for needed additional tokens.

If the history starts with a System message, it is always preserved. Messages are removed from the front (oldest first) until budget.try_reserve(needed) succeeds or only the system message remains.

Returns the number of messages removed.

pub fn into_request(self, system_prompt: impl Into<String>) -> LLMRequest

Convert the history into an LLMRequest with the given system prompt.

Always sets the request’s system field to system_prompt. Any System messages in the history are filtered out of the message list, since the system prompt is conveyed via the request’s system field. The request is created with a default temperature of 0.7.

Trait Implementations

impl Clone for ConversationHistory

fn clone(&self) -> ConversationHistory

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ConversationHistory

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

Formats the value using the given formatter.

impl Default for ConversationHistory

fn default() -> Self

Returns the “default value” for a type.