Arun Arumugam

Themessteady

Sandboxes and limits for agents that act

As agents run code and spend money, containment is getting real engineering. Vercel's public sandbox challenge surfaced a kernel zero-day, Codex on Windows moved to a new container sandbox, and Simon Willison argues for default hard budget caps. Isolation and limits are becoming table stakes.

Feed

  1. VercelBlogSecurityFindings from the $1M Vercel Sandbox challengeAn open challenge to break out of Vercel's agent sandbox drew 1,285 reports, found a Linux kernel zero-day and paid $242K. Real data on how well agent isolation holds up.

  1. OpenAI DevelopersReleaseSecurityCodex on Windows gets a new sandbox built on Microsoft Execution ContainersFaster setup and stronger network enforcement for agents running code on Windows, which matters for safely letting agents act locally.

  1. Simon WillisonBlogAgentsWe are going to need default hard budget caps on pretty much everythingAs agents call paid APIs on their own, runaway bills become a real risk. Willison makes the case that hard spending limits should be on by default.