children = await rlm.list_subagents()
child = next((item for item in children if item.active_session_id), None)
if child is not None:
    receipt = await agent_message.send(
        "Please inspect the latest result.",
        receiver_role="child",
        receiver_name=child.session_name,
    )
    # Keep the child until this follow-up finishes so its result remains observable.

API

await agent_observe.list_agents() (agent-observe skill) is the roster: it lists the parent, siblings, and children this skill can reach, active or not, with the relationship and sessionName that send takes as receiver_role and receiver_name.
await agent_message.send(message, receiver_role="parent" | "sibling" | "child", receiver_name=None) — sends one direct text message to one family member. Sending to an inactive or idle completed subagent wakes it and starts an ordinary follow-up turn in that same session and context. The child remains available only until its parent session closes. The daemon resolves receiver_role within the current agent family; receiver_name is required for siblings and children and omitted for the unique parent. send("all", message) broadcasts only to the family roster and returns {receipts: [...]} in roster order; successful entries are ordinary receipts and failed entries contain the target id and a short error. One failed delivery does not reject successful deliveries. Messages always use steering delivery so a busy target sees them during its active run. Returns a receipt with a deliveryStatus field: "delivered" means the message reached an idle target's context; "queued" means a steering message was accepted and will deliver when the target's current work allows (send does not block waiting for that). Delivered receipts carry deliveredAt, queued receipts carry queuedAt.

Safety

Do not delete a child immediately after send: delivered follow-ups may still be running and queued receipts have not run yet. Wait until observation shows the child is idle and its context is no longer needed before calling await rlm.delete_subagent(child).
Reach is limited to parent, siblings, and direct children; relay through an intermediate child instead of messaging grandchildren or cousins directly.
Sender identity is daemon-derived and cannot be spoofed from Python.
The daemon enforces message size, rate, and pending-queue limits before accepting delivery.

agent-message

Agent Message