Vercel Agent can now install private packages from npm and custom registries

What the update does

Until now, an agent working in a project that depends on private code could run into a basic obstacle: it could not fetch packages that sit behind authentication. Vercel says that is addressed. Vercel Agent can install private dependencies from npm as well as from custom registries.

The package managers npm, pnpm and classic Yarn are covered. According to Vercel, when they run inside Agent sessions they authenticate in the same way they do in Vercel builds. Teams that already have private packages working in their deployment pipeline should therefore find that the agent follows a familiar pattern.

How to set it up

Setup relies on shared environment variables. Vercel says users should add a shared environment variable for Development or Preview. Which variable to use depends on where the packages are hosted:

• NPM_TOKEN is for private packages hosted on registry.npmjs.org.
• NPM_RC is for configuring custom or multiple registries.

The split matters for teams with different needs. A team that only uses private packages from the public npm registry can supply a token. A team that pulls from a custom registry, or from several registries at once, can use NPM_RC to describe that configuration.

Vercel also specifies a scope limit. Vercel Agent reads only team-shared variables, not project-scoped ones. Anyone who has stored a registry token at the project level will need to define it as a shared variable at the team level for the agent to pick it up.

Credentials stay out of the agent's reach

Handing an automated agent registry credentials raises an obvious concern about exposure. Vercel states that credential values stay outside the sandbox, so "the agent cannot read them." The installation step can authenticate with the registry, while the agent itself has no access to the secret values.

Details on configuration are in Vercel's private dependencies documentation, which the changelog points to for further reading.

What it means for teams

For teams that depend on internal or paid packages, the change removes a gap that could limit what Vercel Agent is able to do in their projects. Because authentication works like it does in builds, and because secrets are kept out of the sandbox, teams can use the agent on codebases with private dependencies without changing how they manage package access.

The practical steps are limited: create a team-shared variable for Development or Preview, choose NPM_TOKEN or NPM_RC depending on the registry setup, and make sure the variable is not only defined at project scope.