Unreal Labs has released Unreal Agent, a general-purpose agent harness written in Go and distributed under the MIT license. The company claims the harness can cut agent costs by up to 40 percent without reducing task performance. Its headline result is a 39 percent cost reduction against Codex plus Astra on Terminal-Bench 4.0, with a roughly equivalent pass rate.

Unreal Agent changes the orchestration layer around a language model. An agent harness manages prompts, tool calls, execution state, and results; it does not supply a new model. Unreal Labs attributes the reported savings to asynchronous tool execution, compact prompts, token-efficient outputs, and a deliberately small tool surface. The source, setup instructions, and examples are available in the GitHub repository, alongside a companion design post.

Async execution without polling

Long-running tools execute as asynchronous operations, which lets the model submit several independent calls during one turn. The coordinator tracks those operations and consumes their results as they complete. Users can also send new instructions while tools remain active, avoiding a forced wait for every command to finish.