# Agent projects expose limits of sandboxing for agent fleets > Source: > Published: 2026-07-07 11:30:00+00:00 CNCF Ambassador **Lin Sun** of Solo.io wrote on **July 7, 2026** that sandboxing alone is not enough to run large-scale AI agent fleets, contrasting the **Kubernetes SIG Apps** project `agent-sandbox` with a newer, still-standalone project called `agent-substrate`. Agent-sandbox provides identity, persistent storage, and lifecycle management for sandboxed agent pods; agent-substrate goes further by dynamically waking agents on invocation using lightweight sandboxes such as gVisor or Kata Containers, letting many agents share one worker pool instead of running as always-on pods. Sun's team is exploring integrating agent-substrate with `kagent` and `agentgateway`. For practitioners, the takeaway is that secure isolation and fleet-level operational efficiency are separate problems, and both need solving to run agents at scale.