May 15, 2026 · The Harbor Team
Starting today, you can verify Harbor tasks in a separate sandbox from the one used by the agent. In `task.toml`, you can specify artifacts to copy between the agent sandbox and verifier sandbox. Verifying in a separate sandbox: * enables different resource configurations or dependencies than the agent sandbox * lets users pre-bake dependencies into a verifier image to avoid flaky package installation * provides an additional security boundary between the agent and the verification process It also introduces constraints: * verification is limited to copied artifacts, not full container state such as running processes * tasks must explicitly write anything the verifier needs to an artifact path Separate verification works for both single-step and multi-step tasks. Multi-step tasks can opt into a separate verifier sandbox per step. To start using this feature, update the `create-task` skill: ```bash theme={"system"} npx skills add harbor-framework/harbor --skill create-task ``` Or add the following sections to your `task.toml`: ```toml theme={"system"} artifacts = ["/tmp/answer.json"] [verifier] environment_mode = "separate" ``` You can also configure the verifier sandbox: ```toml theme={"system"} artifacts = ["/tmp/answer.json"] [verifier] environment_mode = "separate" [verifier.environment] network_mode = "no-network" # baseline; [verifier].network_mode is an optional phase override cpus = 2 memory_mb = 4096 ``` Per-step verifier config uses `[steps.verifier]` and `[steps.verifier.environment]` with the same rules. Opting in treats the `tests/` directory as an environment directory, similar to `environment/`. As usual, we're excited to see what you build and welcome feedback!