mosaic comms: socket resolution is tool-owned (B2) (#1476)

Co-authored-by: marcie <[email protected]>

packages/mosaic/src/commands/comms.spec.ts

@@ -15,6 +15,17 @@ import { afterEach, describe, expect, it } from 'vitest';
 import { fleetCommsSendArgs, registerCommsCommand, tmuxSendArgs } from './comms.js';
 
 describe('arg translation', () => {
+  // B2 (2026-08-29): when --socket is omitted, the CLI forwards NO -L and
+  // agent-send.sh's own resolution governs (explicit -L > MOSAIC_TMUX_SOCKET
+  // > unique hit > ambiguity refusal). Forwarding a guessed default here
+  // would defeat that resolution and reintroduce the stale-twin defect.
+  it('omits -L entirely when --socket is not given (tool-owned resolution)', () => {
+    const args = tmuxSendArgs('orch-01', 'hello', {});
+    expect(args).toEqual(['-s', 'orch-01', '-m', 'hello']);
+    expect(args).not.toContain('-L');
+    expect(args.join(' ')).not.toContain('-L');
+  });
+
   it('tmux path: -s/-C/-L/-f/-m per agent-send.sh getopts', () => {
     expect(tmuxSendArgs('orch-01', 'hello', {})).toEqual(['-s', 'orch-01', '-m', 'hello']);
     expect(