Struct MessageEnvelope 

pub struct MessageEnvelope {
    pub id: Uuid,
    pub sender: Uuid,
    pub recipient: MessageTarget,
    pub payload: Payload,
    pub timestamp: DateTime<Utc>,
    pub ttl: Option<u32>,
    pub correlation_id: Option<Uuid>,
    pub trace_id: Option<Uuid>,
}

A message envelope that wraps any payload with routing metadata.

This is the universal message format used across all transports. Transports serialize/deserialize envelopes to their wire format.

Fields

id: Uuid

Unique message identifier.

sender: Uuid

The sender’s agent identity UUID.

recipient: MessageTarget

Who this message is addressed to.

payload: Payload

The message payload.

timestamp: DateTime<Utc>

When the message was created.

ttl: Option<u32>

Optional time-to-live (number of hops before the message is dropped).

correlation_id: Option<Uuid>

Optional correlation ID for request-response patterns.

trace_id: Option<Uuid>

Optional trace ID for cross-system event correlation.

Set this to the same UUID used by the originating TaskAgent so that network hops can be joined with audit log entries and A2A stream events.

Implementations

impl MessageEnvelope

pub fn direct( sender: Uuid, recipient: Uuid, payload: impl Into<Payload>, ) -> Self

Create a new envelope addressed to a specific agent.

pub fn broadcast(sender: Uuid, payload: impl Into<Payload>) -> Self

Create a new broadcast envelope.

pub fn topic( sender: Uuid, topic: impl Into<String>, payload: impl Into<Payload>, ) -> Self

Create a new topic-addressed envelope.

pub fn with_ttl(self, ttl: u32) -> Self

Set the TTL on this envelope.

pub fn with_correlation(self, correlation_id: Uuid) -> Self

Set a correlation ID for request-response tracking.

pub fn reply(&self, sender: Uuid, payload: impl Into<Payload>) -> Self

Create a reply envelope to this message.

The reply inherits the sender’s trace_id so the full request-response exchange shares one trace.

pub fn with_trace(self, trace_id: Uuid) -> Self

Attach a trace ID to this envelope (builder pattern).

Trait Implementations

impl Clone for MessageEnvelope

fn clone(&self) -> MessageEnvelope

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MessageEnvelope

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for MessageEnvelope

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for MessageEnvelope

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

where __S: Serializer,

Serialize this value into the given Serde serializer.