> ## Documentation Index
> Fetch the complete documentation index at: https://docs.anpord.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Harnesses, models, and sandboxes

> Choose what runs a case and where it runs

Each entry in `tasks` defines one variant:

```ts theme={null}
{ harness: "codex", model: "gpt-5.6-sol", provider: "daytona" }
```

| Field      | Purpose                               |
| ---------- | ------------------------------------- |
| `harness`  | Runs the agent and its tools          |
| `model`    | Selects the model used by the harness |
| `provider` | Supplies the sandbox                  |

Today, `harness` must be `codex`; Claude Code is not supported yet. The field stays explicit so future harnesses can use the same case format.

## Choose a model

Keep the model id in application or CI configuration. Use the catalogue when choosing or changing it:

```ts theme={null}
const { models } = await anpord.evals.models({ harness: "codex" });

for (const model of models) {
  console.log(model.id, model.displayName);
}
```

Model discovery is not required before `evals.start`. Available ids depend on the account configured on the server.

## Choose a sandbox

| Provider     | Availability                                          |
| ------------ | ----------------------------------------------------- |
| `daytona`    | Public API and dashboard                              |
| `e2b`        | Public API and dashboard                              |
| `upstash`    | Public API and dashboard                              |
| `modal`      | Public API and dashboard                              |
| `cloudflare` | Public API and dashboard                              |
| `vercel`     | Public API and dashboard                              |
| `local`      | Trusted dashboard development on a self-hosted server |

Each trial gets a separate workspace. Setup, agent work, and verification run in that workspace.

<Warning>
  `local` is not isolated from the server process. The public API and SDK do not accept it.
</Warning>

## Compare variants

Change one field at a time when you want to explain the difference:

```ts theme={null}
tasks: [
  { harness: "codex", model: "gpt-5.6-sol", provider: "daytona" },
  { harness: "codex", model: "gpt-5.6-terra", provider: "daytona" },
]
```

Changing the harness, harness version, model, or provider creates a new cell history and baseline.