Struct LoopCheckpoint 

pub struct LoopCheckpoint {
    pub messages: Vec<LlmMessage>,
    pub custom_messages: Vec<Value>,
    pub pending_messages: Vec<LlmMessage>,
    pub pending_steering_messages: Vec<LlmMessage>,
    pub system_prompt: String,
    pub provider: String,
    pub model_id: String,
    pub created_at: u64,
    pub metadata: HashMap<String, Value>,
    pub state: Option<Value>,
    /* private fields */
}

A serializable snapshot of the agent loop’s in-flight state.

Captures everything needed to pause a running loop and resume it later: messages, pending injections, system prompt, model, and session state. Created by Agent::pause and consumed by Agent::resume.

Fields

messages: Vec<LlmMessage>

All context messages at the time of pause.

custom_messages: Vec<Value>

Serialized custom messages (envelopes with type and data fields).

pending_messages: Vec<LlmMessage>

Follow-up messages queued for injection into the next turn.

pending_steering_messages: Vec<LlmMessage>

Steering messages queued at the time of pause.

Older checkpoints without this field deserialize with an empty vec (backward compatible).

system_prompt: String

The system prompt active at the time of pause.

provider: String

Model provider name.

model_id: String

Model identifier.

created_at: u64

Unix timestamp when the checkpoint was created.

metadata: HashMap<String, Value>

Arbitrary metadata for application-specific use.

state: Option<Value>

Serialized session state snapshot (SessionState.data).

Implementations

impl LoopCheckpoint

pub fn new( system_prompt: impl Into<String>, provider: impl Into<String>, model_id: impl Into<String>, messages: &[AgentMessage], ) -> Self

Create a loop checkpoint from the current agent state.

Serializes CustomMessage variants that support serialization. Non-serializable custom messages are skipped with a warning.

pub fn with_state(self, state: Value) -> Self

Set the session state snapshot.

pub fn with_pending_messages(self, pending: Vec<LlmMessage>) -> Self

Set pending follow-up messages.

pub fn with_pending_steering_messages(self, pending: Vec<LlmMessage>) -> Self

Set pending steering messages.

pub fn with_pending_message_batch(self, pending: &[AgentMessage]) -> Self

Set pending follow-up messages from a full AgentMessage batch.

pub fn with_pending_steering_message_batch( self, pending: &[AgentMessage], ) -> Self

Set pending steering messages from a full AgentMessage batch.

pub fn with_metadata(self, key: impl Into<String>, value: Value) -> Self

Add metadata.

pub fn restore_messages( &self, registry: Option<&CustomMessageRegistry>, ) -> Vec<AgentMessage>

Restore all messages as AgentMessage values, preserving their original interleaved order.

If registry is None, custom messages are silently skipped.

pub fn restore_pending_messages( &self, registry: Option<&CustomMessageRegistry>, ) -> Vec<AgentMessage>

Restore pending follow-up messages as AgentMessage values.

pub fn restore_pending_steering_messages( &self, registry: Option<&CustomMessageRegistry>, ) -> Vec<AgentMessage>

Restore pending steering messages as AgentMessage values.

pub fn to_checkpoint(&self, id: impl Into<String>) -> Checkpoint

Convert this loop checkpoint into a standard Checkpoint for storage.

Trait Implementations

impl Clone for LoopCheckpoint

fn clone(&self) -> LoopCheckpoint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LoopCheckpoint

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for LoopCheckpoint

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for LoopCheckpoint

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.