Give every agent in Herdr its own Vercel Sandbox
By Steven Van ·
Terminal coding agents like Claude Code, Codex, and OpenCode can now each run in their own isolated Vercel Sandbox, orchestrated from Herdr, a tmux-style…
Herdr, a tmux-style manager for running terminal coding agents side by side, now launches each agent in its own Vercel Sandbox instead of on the local machine. Nothing an agent runs or edits touches the user's computer: starting an agent uploads the project files into a new Sandbox, installs the agent there, and opens a pane connected to it, so several agents can run at once without slowing the machine down.
- Claude Code (2.1.220), Codex (0.146.0), and OpenCode (1.18.9) are verified and available by default.
- Every plugin action returns JSON, so starting an agent, checking its state, or applying its changes can be done by a script or another agent, not just from a pane.
- Safeguards: the plugin lists every file before the first upload, returns remote changes as a Git patch that's only applied when the user chooses, and requires typing DELETE to remove a Sandbox permanently.
To get started, install the plugin with herdr plugin install vercel-labs/herdr-vercel-sandbox-plugin, run vercel link in the target repository, then start an agent from Herdr's action menu. The first start is a dry run listing what would be uploaded; running it again creates the Sandbox and opens the agent. Usage is billed at standard Sandbox rates.
