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

# Call decision models

> Call System One decision models such as TypeSafe's Jev through LLM Gateway 2.0 for typed answers with calibrated probabilities for routing and classification.

Decision models such as TypeSafe's Jev don't generate text. You send a piece of state and a set of typed questions, and the model returns a typed answer to each, with calibrated probabilities. Use them for routing, classification, gating, and guardrail checks where you need a fast, cheap, machine-readable answer.

## Question types

| Type | Returns |
| :- | :- |
| `noul` | The probability that a statement is true. |
| `choice` | One of up to 255 options. |
| `score` | A position on an ordered scale of 2 to 10 levels. |

## Add a provider

| Provider type | Use it for | Base URL |
| :- | :- | :- |
| TypeSafe (Jev) | TypeSafe's own API | Leave blank |
| System One compatible | Any other host of the same protocol, including OpenRouter, Vercel AI Gateway, Codiv, self-hosted OpenJev, and LiteLLM | The host's base URL, without `/v1` |

Model names differ by host, for example `jev-latest` on TypeSafe and `typesafe/jev-1.13` on OpenRouter. The built-in price book covers the Jev models.

## Call a decision alias

Send `POST /v1/systemone` with a decision alias as `model`. The TypeSafe software development kit (SDK) works if you set its `baseURL` to the gateway root.

In the Playground, picking a decision alias opens a decision editor where you build questions, see answers as probability distributions, and copy Python, TypeScript, or cURL snippets.

## What applies to decision aliases

Grants, budgets, bring your own token (BYOT) grants, tag headers, input guardrails on `state`, caching, and retries all apply. Streaming, fallback chains, and output guardrails don't.

A decision alias can't serve chat, responses, embeddings, or Claude Code, and returns a `400` if you try.

## Related

* [Control access, spend, and usage](/cloud/admin/platform-configuration/llm-gateway/access-and-spend): grant access to decision aliases and set budgets.
* [Configure guardrails and fallback routing](/cloud/admin/platform-configuration/llm-gateway/guardrails-and-fallback#guardrails): screen the `state` you send.


## Related topics

- [LLM Gateway 2.0](/cloud/platform-capabilities/features/llms/llm-gateway/index.md)
- [Getting started with Domino: Build a transaction review App](/cloud/platform-overview/getting-started-with-domino/index.md)
- [Set up LLM access](/cloud/platform-capabilities/features/llms/index.md)
- [Monitor model endpoints](/cloud/platform-capabilities/features/model-deployment/monitor-model-endpoints.md)