One Account for the Whole Agent

For the last few months ConTree ran as a standalone early access program. You filled in a form, we minted a token, you pointed your code at our endpoint. That worked, but it was a parallel universe to the rest of Nebius: separate sign-up, separate token, separate bill.

That's the bit that changes today. ConTree now ships as Sandboxes inside Nebius Token Factory — the platform where Nebius already serves open-weight and frontier model inference and runs fine-tuning. Token Factory is generally available; Sandboxes is the new product inside it and is currently in beta.

For a typical agent loop — model proposes an action, sandbox runs it, the result feeds the next prompt — this means one account for both halves. One token, one dashboard, one support channel.

What's Inside the Sandboxes Beta

The product behind the name is the same ConTree you may already know:

  • Safe execution — every command runs in a dedicated microVM, isolated from the host and from other tenants.
  • Git-like branching — every run produces an immutable image you can fork from, run in parallel with others, and roll back to instantly.
  • Bring-your-own images via OCI registry import, or pick from a public catalogue of more than 39,000 pre-built SWE-bench environments ready to use.
  • Three clients, one API. Use the Python SDK for code, the MCP server for Claude Code / Claude Desktop / Codex, or the new contree-cli from a terminal or shell script.

contree-cli: a Third Way In

The most visible addition since the previous announcement is the command-line client. contree-cli is a stdlib-only Python package — nothing to pull in except itself — that talks to the same API the SDK and MCP server use.

pip install contree-cli
contree auth                            # one-time setup
eval $(contree use tag:ubuntu:latest)   # pick a base image for current session
contree run apt-get update -qq          # each run snapshots the result
contree session branch experiment       # branch the sandbox state
contree run -- make test
contree session checkout main           # switch back instantly

It's handy for ad-hoc work and as a building block in shell-based agent toolchains.

One Command for Local Agents

If you run a local coding agent — Claude Code, Codex, OpenCode, Cline, or Amp — contree-cli ships ready-made skills for all of them. A single command autodetects what's installed on your machine and drops the right files in the right places:

contree skill install

The agent then knows how to spin up sandboxes, branch state, and roll back without you wiring anything up by hand. Full reference at docs.contree.dev/cli.

How to Get Access

Head to tokenfactory.nebius.com/sandboxes/about. If you don't have a Nebius account yet, register or sign in via OAuth first — that takes a minute — then apply for the Sandboxes beta from the same page. Existing Nebius users skip straight to the apply step.

Approval flips the Sandboxes feature on for your project. There is no new token to issue: the Nebius API token you already have starts working against the ConTree endpoints, with the SDK, MCP server, and CLI. The Token Factory page also exposes an in-browser CLI you can use without installing anything.

Questions, migration help, or research collaboration: contree@nebius.com.

Migrating from the Early Access

If you already have a ConTree token from the old early access program, here is what to know:

  • Existing tokens keep working until they expire. After that, fresh tokens come exclusively from Token Factory — the old intake form no longer mints credentials.
  • The service endpoint is now https://api.tokenfactory.nebius.com/sandboxes. It is the default in the current CLI and SDK; you only need to update older clients you may have pinned.
  • Authorization is now Nebius IAM. Token Factory issues IAM tokens scoped to a project; the SDK, MCP server, and CLI all accept them. Legacy JWT tokens continue to work on the wire until they expire.
  • CLI users on 0.4.5 or earlier: upgrade to the latest contree-cli. The auth/env-var precedence was reworked (only contree auth reads CONTREE_TOKEN / CONTREE_URL / CONTREE_PROJECT and the NEBIUS_* aliases now), and the config moved to ~/.config/contree/auth.ini. The CLI migrates the old path automatically.

The shape of the HTTP API itself — resources, payloads, semantics — did not change. Neither did the SDK or MCP tool surfaces.