Struct AgentExecutionResult 

pub struct AgentExecutionResult {
    pub event: PipelineEvent,
    pub session_id: Option<String>,
}

Result of executing an agent.

Contains the pipeline event and optional session_id for session continuation.

Session ID Handling

When session_id is Some, the handler MUST emit a separate SessionEstablished event to the reducer. This is the proper way to handle session IDs in the reducer architecture - each piece of information is communicated via a dedicated event.

The handler should:

1. Process event through the reducer
2. If session_id.is_some(), emit SessionEstablished and process it

This two-event approach ensures:

• Clean separation of concerns (success vs session establishment)
• Proper state transitions in the reducer
• Session ID is stored in agent_chain.last_session_id for XSD retry reuse

Fields

event: PipelineEvent

The pipeline event from agent execution (success or failure).

session_id: Option<String>

Session ID from agent’s init event, for XSD retry session continuation.

When present, handler must emit SessionEstablished event separately.