> ## Documentation Index > Fetch the complete documentation index at: https://docs.gloo.com/llms.txt > Use this file to discover all available pages before exploring further. # System One Decisions > POST /xds/v2/sys1 — ask structured questions about your application's state and get typed answers with probabilities. System One is a decision model. You send your application's current `state` and a set of `questions`, and it answers each one with a typed result you can check in code, such as a choice with a probability for every option. Use it when your application has to make a decision, for example routing, triage, moderation or picking the next step in a workflow, and you would otherwise have to parse free text. ## Prerequisites * A Gloo AI Studio account * Your API key from the [API Credentials page](https://docs.gloo.com/studio/manage-api-credentials.md) * **Authentication setup** - Complete the [Authentication Tutorial](https://docs.gloo.com/tutorials/authentication.md) first ## Quick start **URL:** `https://platform.ai.gloo.com/xds/v2/sys1` **Operation:** `POST` ```bash cURL theme={null} curl -X POST 'https://platform.ai.gloo.com/xds/v2/sys1' \ -H "Authorization: Bearer ${GLOO_API_KEY}" \ -H 'Content-Type: application/json' \ -d '{ "state": { "ticket": "I was charged twice for my subscription this month.", "customer_tier": "pro" }, "questions": { "category": { "type": "choice", "instructions": "Which team should handle this ticket?", "criteria": { "billing": "Payments, invoices, refunds, or charges.", "technical": "Bugs, errors, or how the product works.", "account": "Login, profile, or account settings." } }, "wants_refund": { "type": "noul", "instructions": "The customer is asking for their money back." } } }' ``` ```python Python theme={null} import os, requests resp = requests.post( "https://platform.ai.gloo.com/xds/v2/sys1", headers={"Authorization": f"Bearer {os.environ['GLOO_API_KEY']}"}, json={ "state": { "ticket": "I was charged twice for my subscription this month.", "customer_tier": "pro", }, "questions": { "category": { "type": "choice", "instructions": "Which team should handle this ticket?", "criteria": { "billing": "Payments, invoices, refunds, or charges.", "technical": "Bugs, errors, or how the product works.", "account": "Login, profile, or account settings.", }, }, "wants_refund": { "type": "noul", "instructions": "The customer is asking for their money back.", }, }, }, timeout=30, ) resp.raise_for_status() answers = resp.json()["answers"] print(answers["category"]["choice"], answers["wants_refund"]["noul"]) ``` ```javascript JavaScript theme={null} const resp = await fetch("https://platform.ai.gloo.com/xds/v2/sys1", { method: "POST", headers: { Authorization: `Bearer ${process.env.GLOO_API_KEY}`, "Content-Type": "application/json", }, body: JSON.stringify({ state: { ticket: "I was charged twice for my subscription this month.", customer_tier: "pro", }, questions: { category: { type: "choice", instructions: "Which team should handle this ticket?", criteria: { billing: "Payments, invoices, refunds, or charges.", technical: "Bugs, errors, or how the product works.", account: "Login, profile, or account settings.", }, }, wants_refund: { type: "noul", instructions: "The customer is asking for their money back.", }, }, }), }); if (!resp.ok) { throw new Error(`System One returned ${resp.status}: ${await resp.text()}`); } const { answers } = await resp.json(); console.log(answers.category.choice, answers.wants_refund.noul); ``` #### Example response ```json theme={null} { "id": "gen-dec-1793981370-uOwFt34AIeyibLNhYu26", "model": "typesafe/jev-1.13-20260917", "provider": "TypeSafe", "answers": { "category": { "type": "choice", "choice": "billing", "confidence": 1, "probabilities": { "account": 0, "billing": 1, "technical": 0 } }, "wants_refund": { "type": "noul", "noul": 0.66 } }, "usage": { "input_tokens": 386, "output_tokens": 58 } } ``` ## Question types | Type | Ask it when | `criteria` | Answer | | - | - | - | - | | `choice` | One of several options applies. | Required. Maps each option key to a description of when to pick it. | `choice`, `confidence` and `probabilities` | | `noul` | A statement is either true or false of the state. | Optional. | `noul`, the probability from 0 to 1 that the statement is true | ## Writing questions * Give each question a key that is unique in `questions`. The key appears again in `answers`. * Write `instructions` as the question for a `choice`, and as a statement that is true or false for a `noul`. * Write `choice` criteria that do not overlap, and add a fallback option such as `"other"` or `"none"` so the model does not have to force a choice. * Put everything the model needs in `state`. It can be a string, or a JSON object or array of related context. A structured object keeps separate facts separate. * Act on the numbers rather than on the top answer alone. For example, act automatically only above 0.9 and send anything lower to a person. Identical requests can return slightly different probabilities. ## Request parameters | Field | Type | Required | Description | | - | - | - | - | | `state` | string, object or array | Yes | The content System One reads to answer the questions. | | `questions` | object | Yes | Map of question key to question object. | | `questions..type` | string | Yes | `choice` or `noul`. | | `questions..instructions` | string | Yes | The question or statement to evaluate. | | `questions..criteria` | object | For `choice` | Map of option key to a description of when to pick it. | | `session_id` | string | No | Your session identifier, for correlation. Up to 256 characters. | | `user` | string | No | Your end-user reference. | | `trace` | object | No | Your trace data. | The service drops any other top-level field, including `assets`, so images are not accepted. You cannot select the model: Gloo AI chooses it, ignores any `model` you send, and returns the version that answered in the response. ## Response fields | Field | Type | Description | | - | - | - | | `id` | string | The identifier of this decision. | | `model` | string | The versioned model that answered. | | `provider` | string | The provider that served the model. | | `answers` | object | One entry for each key in your `questions`. | | `answers..type` | string | The question type. | | `answers..choice` | string | `choice` only. The option key the model picked. | | `answers..probabilities` | object | `choice` only. Option key to probability. | | `answers..confidence` | number | `choice` only. The model's confidence in its choice. This is a separate value from the chosen option's probability. | | `answers..noul` | number | `noul` only. The probability that the statement is true. | | `usage.input_tokens` | integer | Input tokens. | | `usage.output_tokens` | integer | Output tokens. | Responses are JSON, not a stream. ## Data retention System One requests are always sent with zero data retention required. You do not need to set anything, and no request field can turn it off. ## Pricing System One is billed to your [organization](https://docs.gloo.com/getting-started/glossary.md#organization) per token at the provider's list rate, with no markup. For the current model, TypeSafe Jev 1.13, that is \$0.042 per million input tokens with no charge for output tokens. The cost is not returned in `usage`. ## Errors Use the HTTP status to decide what to do. When Gloo refuses a request, the body looks like this: ```json theme={null} { "error": { "message": "state is required", "type": "invalid_request_error", "code": 1001, "fault": "client", "retryable": false } } ``` Missing or invalid credentials and errors from the provider use other shapes, so do not rely on these fields being present. | Status | Cause | Retry? | | - | - | - | | `400` | The body is not a single JSON object, `state` is missing, `questions` is not an object, or the provider rejected a question. | No. Fix the request. | | `401` | The API key is missing or not valid. | No. | | `402` | Your organization is out of credit. | Not until you add credit. | | `403` | The provider refused the content of the request, or your organization has no active billing account. | No. | | `413` | The request body is larger than 32 MB. | No. Reduce the size. | | `429` | Your organization reached its [spending limit](https://docs.gloo.com/studio/billing.md#spend-limits), or the provider is [rate limiting](https://docs.gloo.com/api-reference/general/limits.md) the model. If `error.type` is `billing_error`, it is the spending limit. Anything else is a rate limit. | Spending limit: not until it is resolved. Rate limit: yes, after the time in the `Retry-After` header if present, otherwise with backoff. | | `5xx` | The service or the provider is temporarily unavailable. | Yes, with backoff. | See the [error reference](https://docs.gloo.com/api-reference/general/errors.md) for general guidance. ## Next steps > [card] [API Reference: System One Decisions](https://docs.gloo.com/api-reference/system-one/v2.md) > > The full request and response schemas. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.