Vercel Sandbox Runs Multiple Agents Per Instance

Vercel now lets multiple agents share one Sandbox instance instead of spinning up a separate sandbox for each one, per the company's changelog. The @vercel/sandbox SDK adds support for multiple Linux users and groups. Each agent gets its own user account and a private home directory instead of one shared filesystem.

That kills a real cost for multi-agent pipelines built on Vercel. Isolating agents by filesystem used to mean paying for a full sandbox per agent, even for lightweight work.

Consolidating into one sandbox cuts both the compute cost and the cold-start delay of spinning up several instances at once.

The isolation isn't total by design. Vercel added a shared group alongside the per-agent users, so agents can pass files to each other on purpose. That's the right call for pipelines where one agent's output feeds directly into the next step.

It surfaced in coverage dated July 31, logged as a changelog entry on Vercel's site.

The isolation is Linux users and groups sharing one kernel, not separate virtual machines. That's a fine tradeoff for agents you control, less so for code you don't trust running in the same sandbox.