Tart and Lume

ushr supports Tart as its default macOS driver. Lume is a supported alternative driver.

Tart

Tart is the default driver on macOS hosts. ushr login installs it with Homebrew and checks for the runner image.

brew install openai/tools/tart

Tart's status

  • Cirrus Labs announced on 7 April 2026 that it joined OpenAI.
  • Tart moved to github.com/openai/tart, and OpenAI maintains it.
  • On 5 June 2026 Tart changed to the Functional Source License 1.1 (FSL-1.1-ALv2). Each Tart version becomes Apache-2.0 two years after its release.
  • The current release is 2.40.1 (30 September 2026), from the openai/tools Homebrew tap. The cirruslabs/cli tap stopped at 2.32.1, which uses the older Fair Source licence.

ushr continues to support Tart. To use Lume instead, move a host to Lume. The rest of ushr does not change.

Move a host to Lume

  • Install the lume CLI and put it on your PATH.
  • Create a base macOS VM in lume. It must accept SSH as the user admin.
  • Change the driver block in agent.yaml.
  • Restart the agent, then run ushr doctor.
driver:
  type: lume
  image: YOUR_LUME_BASE_VM
  capacity: 2

Restart the agent with ushr login (hosted) or ushr setup (self-hosted). Both offer to restart the service.

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