# RFC-0011: Session Spawn Primitive

**Status:** Draft \| **Updated:** 2026-02-17

## Summary

Defines a deterministic syscall to spawn a child cognitive session from
a control-plane supervisor/router.

## API

`session_spawn(parent_session_id, request_id, target_agent, payload) -> child_session_id`

## Preconditions

-   Caller has `cap.session.spawn`.
-   Payload is recorded (or hashed) for auditability.
-   Spawn emits a `session_spawn` ledger event (RFC-0009).

## Postconditions

-   A child session exists with its own stream_id.
-   Parent stream contains `session_spawn` pointing to child session_id.
-   Child stream begins with a genesis event referencing parent spawn
    context.

## Security

-   Child inherits only explicit capabilities (no ambient authority).
-   Parent cannot read child internal chain-of-thought unless explicitly
    granted (separate capability).

## Observability

Record: - target_agent - payload_hash - resource limits (if any) -
parent/child linkage