/**
 * `agents mailboxes` — fleet comms: a read-only window onto the agent mailbox spool.
 *
 * The mailbox spool (`~/.agents/.history/mailbox/<id>/{inbox,processing,consumed}`)
 * is the transport under `agents message` / `agents feed` / `agents teams message`:
 * one box per logical agent (session UUID / teams agentId / loop runId). This
 * command surfaces which boxes exist, how much mail each holds, the messages that
 * flowed BETWEEN agents (including already-consumed ones), and — with `--watch` —
 * the live stream as it happens. Rendering rides the shared comms engine
 * (`lib/comms-render.ts`): masthead, sparkline, aggregate, graphEdges.
 *
 *   agents mailboxes                     overview: masthead + 24h sparkline + boxes + recent log
 *   agents mailboxes <id>                one box in full (inbox / processing / consumed)
 *   agents mailboxes --watch             live tail of cross-box traffic until ⌃C
 *   agents mailboxes --between <a> <b>   one relationship as a thread, either direction
 *   agents mailboxes --graph             who-talks-to-whom adjacency, busiest first
 *   --from/--to/--since                  filter the overview log and the --watch stream
 */
import type { Command } from 'commander';
export declare function registerMailboxesCommand(program: Command): void;
