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

# Sandboxes

> Where trials run: e2b, daytona, or modal.

Every trial runs in its own sandbox on one of three providers. Pick the provider per job with `-e`; the default is `daytona`. Once chosen, the provider is fixed for the job's life, and a resumed job inherits it.

* `e2b`: [E2B](https://e2b.dev/docs)
* `daytona`: [Daytona](https://www.daytona.io/docs), the default
* `modal`: [Modal](https://modal.com/docs)

```bash theme={null}
evolve run \
  -d terminal-bench-4@4.0 \
  -a codex \
  -m gpt-6-astra \
  -e modal \
  -l 5 \
  --watch
```

## Which tasks run where

Not every task can run on every provider, and the catalog says so before any money is spent. `evolve dataset show` lists a verdict per provider for every task.

```bash theme={null}
evolve dataset show terminal-bench-4@4.0
```

A verdict is `ok`, or refused with a reason. A GPU task carries a third form: `ok` with a note that the trial degrades to `modal`, the provider that reserves GPUs. Starting a job whose selected tasks include one that is refused on the chosen provider is rejected at creation with `provider_unsupported`, so nothing is spent on a trial that cannot execute.

Three refusals appear in the verdicts: multi-container tasks run on `e2b` and `daytona` only; a multi-container task under `no-network` runs nowhere, so declare `allowlist` or `public`; and a size above a provider's ceiling refuses on that provider.

| Provider  | Max vCPUs | Max memory | Disk                        |
| --------- | --------- | ---------- | --------------------------- |
| `e2b`     | 8         | 8192 MB    | fixed, 20 GB                |
| `daytona` | 4         | 8192 MB    | sized per task, up to 25 GB |
| `modal`   | 16        | 32768 MB   | fixed, 512 GB               |

Two limits show only when the sandbox is created, as an `INFRASTRUCTURE_ERROR` with the reason in the trial's failure detail. On `daytona` an `allowlist` holds one kind of entry: IP addresses and CIDRs for a single-container task (at most 10), hostnames for a multi-container task (at most 20, `*.` covering a domain). `e2b` and `modal` take both kinds.

Each provider keeps a box alive for at most its own plan's lifetime, 24 hours on `e2b` and `modal`. A timeout stretched past it fails the trial.

## GPU tasks

A task declares `gpus` and `gpu_types` in `[environment]`; `gpu_types` null means any type. GPU compute is paid by the platform; a GPU trial draws your credits for its model calls only. `modal` is the provider that reserves GPUs today, so a GPU task runs on `modal` whatever the job picked, and the trial records the move in `sandbox_provider_degrade`. A queued GPU trial past the fleet's `gpu_concurrency_cap` waits; a GPU count above `modal`'s ceiling is refused at import.

Every settled GPU trial states its compute as an estimate, `gpu_cost`, from the sandbox's lifetime at the provider's list price. It is a separate figure, never added to the model spend; the job sums it as `stats.gpu_cost_usd`. `evolve trial show` prints it as `gpu compute (est.)`, and `unpriced_reason` says why when no honest number exists.

## The analyzer's and the checker's sandbox

Trace analysis and task checks run in sandboxes too. `-e` on `evolve analyze` and on `evolve check`, and `--analyze-provider` on `evolve run`, pick the provider. Omitted, the platform's analysis default applies, `daytona`.