# Host Shell Agent > Fix a failing Rust test suite by compiling and running it, inside a kernel-enforced boundary. Source: [Browse the complete example](https://github.com/everruns/everruns/tree/main/examples/host-shell-agent). Fix a failing Rust test suite by compiling and running it, through the [Host Shell](https://everruns.com/docs/capabilities/host-shell/) capability: real processes on this machine, bounded by a kernel policy. This is a real `gpt-6.1-sol` agent, not a scripted turn. ## What you learn How to give an agent the machine it is running on without giving it the machine: one execution capability, a kernel-enforced write and network boundary, and independent host assertions as the success condition. This is the example the sandboxed [Bashkit Shell](https://everruns.com/docs/capabilities/bashkit-shell/) cannot be. Compiling a crate and running its test binary needs a real toolchain and real child processes; an in-process interpreter over a virtual filesystem has neither. ## Scenario and expected outcome The bundled fixture is a small zero-dependency crate whose `chunk_count` drops the partial final chunk, so two tests fail. The agent must run the suite, read the failure, fix the source, and re-run until it passes. Before the agent starts, the example probes the same containment provider the capability uses and prints what it found: a write inside the workspace succeeds, a write outside it is refused by the kernel, an outbound socket is refused by the kernel. Not a description of the boundary, the boundary. After the turn, Rust code re-runs `cargo test` from the host and fails the process if the suite is still red, if an assertion was edited away, or if a test was marked `#[ignore]`. A confident model answer cannot make a red suite pass. ## Run it Clone the repository and run from its root: ```bash export OPENAI_API_KEY="your-key" cargo run -p everruns-host-shell-agent ``` Type the task interactively, or point it at a directory you keep: ```bash cargo run -p everruns-host-shell-agent -- --interactive cargo run -p everruns-host-shell-agent -- /tmp/chunker ``` With no directory, the fixture is materialized into a fresh temporary one and discarded afterwards. ## Requirements Kernel containment needs macOS, or Linux with Landlock ABI v3 fully enforced (Linux 6.2 or a backport). On a kernel that cannot enforce it, the provider fails closed and the example says so instead of running uncontained. On Linux the policy is applied by a helper process, and this example is its own: `main` routes a `__sandbox-exec` re-exec into the containment worker and names that through `SandboxLauncher::ReexecSelf`, which is what a single-binary embedder does. Nothing else needs to be on disk.