SystemOne

Call decision models via the SystemOne protocol: send business state plus typed questions (choice / noul / score) in one request and receive judgments with probability distributions in one forward pass—no free-form text. Built for ticket routing, content moderation, agent routing, and result verification.

POST/v1/systemone

Authorization

AuthorizationstringheaderRequired

HTTP: Bearer Auth

Security Scheme Type: http
HTTP Authorization Scheme: Bearer API_key. Used to authenticate your account. Manage keys under Metered & Packs > API Key Management.

Request Header

Content-Typeenum<string>Default: application/jsonRequired

Set the request body media type to application/json. Allowed value: application/json

Request Bodyapplication/json

statestring | object | arrayRequired

Business context to decide on: ticket text, a dialogue array, or a structured object. Non-string values are serialized (json.dumps) before inference.

questionsobjectRequired

Question map. Keys are caller-defined question IDs; values are question objects. At least one field is required.

questions.typestringRecommended

Question type: choice (single choice) / noul (yes-no) / score (ordinal scale/rating). If omitted, inferred from criteria.

questions.instructionsstringRecommended

Question description or rubric.

questions.criteriaobject | arrayType-dependent

choice / enum: { "option_id": "description" }, ordered by key, max 255; score: ascending level array or object (default 0..4, max 255); noul / boolean: optional, fixed true / false.

modelstringRequired

Model code; currently fixed to u2-decision

API limits and recommendations

No API limit on the number of questions (recommend ≤ 16; latency grows approximately linearly with the number of questions).
choice options ≤ 255 (recommend ≤ 26; too many options reduce model reasoning quality).
score options ≤ 255 (default 0..4).
Context limit: 131072 tokens; an overlong state will be truncated.

systemone response object

modelstring

Fixed to u2-decision.

answersobject

Answer map keyed by request question IDs; invalid or oversized fields may be missing.

answers.typeString

Matches the question type (choice / noul / score).

answers.choiceString

For choice questions: the selected option name.

answers.noulFloat

P(true)，∈ [0, 1]. A decision can use noul >= 0.5.

answers.scoreFloat

For score questions: the probability-weighted expected level index, which may fall between levels (e.g. 1.43).

answers.probabilitiesObject

Probability of each option / level (sums to 1).

answers.confidenceFloat

Confidence of this answer (returned for choice / score questions).

answers.legendObject

For score questions: level index → level description.

latency_msnumber

Inference latency in milliseconds.

SystemOne decisions

curl -X POST https://maas-api.unisound.com/v1/systemone \
  -H "Authorization: Bearer <api_key>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "u2-decision",
    "state": "Payment still not received 24 hours after checkout; the user cannot access core services and requests immediate handling.",
    "questions": {
      "department": {
        "type": "choice",
        "instructions": "Which team should handle this?",
        "criteria": {
          "billing": "Payment, refund, and billing issues",
          "technical": "Product failures and integration issues"
        }
      },
      "escalate": {
        "type": "noul",
        "instructions": "Should on-call staff be notified immediately?"
      },
      "severity": {
        "type": "score",
        "instructions": "How severe is this issue?",
        "criteria": [
          "Minor issue, no functional impact",
          "Partial impact with workarounds",
          "Core features unavailable, no workaround",
          "Severe business or security impact"
        ]
      }
    }
  }'

200

{
	"model": "u2-decision",
	"request_id": "4682848d-ba43-4e8b-9687-be6cbe4b17a6",
	"latency_ms": 322,
	"answers": {
		"department": {
			"type": "choice",
			"choice": "billing",
			"probabilities": {
				"billing": 0.893309,
				"technical": 0.106691
			},
			"confidence": 0.8933094143867493
		},
		"escalate": {
			"type": "noul",
			"noul": 0.9603611826896667
		},
		"severity": {
			"type": "score",
			"legend": {
				"0": "轻微问题，不影响功能",
				"1": "部分功能受影响，但存在替代方案",
				"2": "核心功能不可用，没有替代方案",
				"3": "造成严重业务或安全影响"
			},
			"probabilities": {
				"0": 0.001159,
				"1": 0.003149,
				"2": 0.98943,
				"3": 0.006263
			},
			"score": 2.000796,
			"confidence": 0.9894295334815979
		}
	},
	"usage": {
		"input_tokens": 335
	}
}