Cross-model audit convergence reference for the plan-auditor and sync-auditor agents. Documents how to invoke the `audit_multi` MCP tool to fan a code review out across the codex and GLM (z.ai) backends in parallel, converge their verdicts with the in-session Claude verdict, and fold the resulting per-backend verdicts + disagreement flag into the audit output. The single skill both audit entry points load — no duplication.