Jev Decisions

Create typed decisions with TypeSafe Jev

curl --request POST \
  --url https://nano-gpt.com/api/v1/decisions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "state": "<string>",
  "questions": {},
  "provider": {},
  "session_id": "<string>",
  "trace": {},
  "user": "<string>"
}
'

import requests

url = "https://nano-gpt.com/api/v1/decisions"

payload = {
    "state": "<string>",
    "questions": {},
    "provider": {},
    "session_id": "<string>",
    "trace": {},
    "user": "<string>"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    state: '<string>',
    questions: {},
    provider: {},
    session_id: '<string>',
    trace: {},
    user: '<string>'
  })
};

fetch('https://nano-gpt.com/api/v1/decisions', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://nano-gpt.com/api/v1/decisions",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'state' => '<string>',
    'questions' => [
        
    ],
    'provider' => [
        
    ],
    'session_id' => '<string>',
    'trace' => [
        
    ],
    'user' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://nano-gpt.com/api/v1/decisions"

	payload := strings.NewReader("{\n  \"state\": \"<string>\",\n  \"questions\": {},\n  \"provider\": {},\n  \"session_id\": \"<string>\",\n  \"trace\": {},\n  \"user\": \"<string>\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://nano-gpt.com/api/v1/decisions")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"state\": \"<string>\",\n  \"questions\": {},\n  \"provider\": {},\n  \"session_id\": \"<string>\",\n  \"trace\": {},\n  \"user\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://nano-gpt.com/api/v1/decisions")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"state\": \"<string>\",\n  \"questions\": {},\n  \"provider\": {},\n  \"session_id\": \"<string>\",\n  \"trace\": {},\n  \"user\": \"<string>\"\n}"

response = http.request(request)
puts response.read_body

{
  "model": "<string>",
  "answers": {},
  "usage": {
    "input_tokens": 1,
    "output_tokens": 1,
    "cost": 1
  },
  "id": "<string>",
  "provider": "<string>"
}

{
  "error": {
    "message": "<string>",
    "type": "<string>",
    "code": "<string>",
    "param": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "type": "<string>",
    "code": "<string>",
    "param": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "type": "<string>",
    "code": "<string>",
    "param": "<string>"
  }
}

POST

decisions

Create typed decisions with TypeSafe Jev

curl --request POST \
  --url https://nano-gpt.com/api/v1/decisions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "state": "<string>",
  "questions": {},
  "provider": {},
  "session_id": "<string>",
  "trace": {},
  "user": "<string>"
}
'

import requests

url = "https://nano-gpt.com/api/v1/decisions"

payload = {
    "state": "<string>",
    "questions": {},
    "provider": {},
    "session_id": "<string>",
    "trace": {},
    "user": "<string>"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    state: '<string>',
    questions: {},
    provider: {},
    session_id: '<string>',
    trace: {},
    user: '<string>'
  })
};

fetch('https://nano-gpt.com/api/v1/decisions', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://nano-gpt.com/api/v1/decisions",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'state' => '<string>',
    'questions' => [
        
    ],
    'provider' => [
        
    ],
    'session_id' => '<string>',
    'trace' => [
        
    ],
    'user' => '<string>'
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://nano-gpt.com/api/v1/decisions"

	payload := strings.NewReader("{\n  \"state\": \"<string>\",\n  \"questions\": {},\n  \"provider\": {},\n  \"session_id\": \"<string>\",\n  \"trace\": {},\n  \"user\": \"<string>\"\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://nano-gpt.com/api/v1/decisions")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"state\": \"<string>\",\n  \"questions\": {},\n  \"provider\": {},\n  \"session_id\": \"<string>\",\n  \"trace\": {},\n  \"user\": \"<string>\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://nano-gpt.com/api/v1/decisions")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"state\": \"<string>\",\n  \"questions\": {},\n  \"provider\": {},\n  \"session_id\": \"<string>\",\n  \"trace\": {},\n  \"user\": \"<string>\"\n}"

response = http.request(request)
puts response.read_body

{
  "model": "<string>",
  "answers": {},
  "usage": {
    "input_tokens": 1,
    "output_tokens": 1,
    "cost": 1
  },
  "id": "<string>",
  "provider": "<string>"
}

{
  "error": {
    "message": "<string>",
    "type": "<string>",
    "code": "<string>",
    "param": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "type": "<string>",
    "code": "<string>",
    "param": "<string>"
  }
}

{
  "error": {
    "message": "<string>",
    "type": "<string>",
    "code": "<string>",
    "param": "<string>"
  }
}

Overview

TypeSafe Jev is a decision model. Instead of generating prose, Jev answers named, typed questions about the state you provide:

choice selects one named option and returns a probability for every option.
score returns an expected score over an ordered rubric.
noul returns the probability that a yes/no statement is true.

For new HTTP integrations, use the native POST /api/v1/decisions endpoint. If you already use the official TypeSafe SDK, point it at NanoGPT’s POST /api/v1/systemone compatibility endpoint. Jev is also available through NanoGPT’s OpenAI-compatible Chat Completions and Responses APIs and the Anthropic-compatible Messages API.

Jev is currently available on https://nano-gpt.com, including the Decisions and System One endpoints and Jev requests through compatible chat APIs. The direct API host does not yet list Jev models or serve its dedicated routes. Use the website host for Jev until the direct host is updated.

Jev returns calibrated probabilities, not generated text. Use a chat model when you need an explanation or other free-form response.

Models

Model	Use
`typesafe/jev-1.13`	Pinned Jev 1.13 release for integrations that should not follow alias upgrades.
`typesafe/jev-latest`	Moving alias for the latest Jev release.

The System One compatibility endpoint also accepts the official SDK model names jev-1.13 and jev-latest. Use the typesafe/... names on the native Decisions and OpenAI/Anthropic-compatible endpoints.

Native Decisions API

Endpoint

POST https://nano-gpt.com/api/v1/decisions

Authenticate with either Authorization: Bearer YOUR_API_KEY or x-api-key: YOUR_API_KEY.

Example request

curl https://nano-gpt.com/api/v1/decisions \
  -H "Authorization: Bearer $NANOGPT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "typesafe/jev-1.13",
    "state": {
      "ticket": "I was charged twice and need this fixed before Friday.",
      "customer_tier": "business"
    },
    "questions": {
      "route": {
        "type": "choice",
        "instructions": "Which team should handle this ticket?",
        "criteria": {
          "billing": "Payments, invoices, refunds, or duplicate charges",
          "technical": "Product behavior, bugs, or integrations",
          "sales": "Plans, pricing, or purchasing"
        }
      },
      "urgency": {
        "type": "score",
        "instructions": "How urgent is the ticket?",
        "criteria": [
          "No time pressure",
          "Can wait several days",
          "Needs attention within one business day",
          "Immediate action is required"
        ]
      },
      "needs_human_review": {
        "type": "noul",
        "instructions": "Does this ticket need human review?",
        "criteria": {
          "true": "A person should review the case",
          "false": "Automation can safely handle the case"
        }
      }
    },
    "user": "customer_123"
  }'

const response = await fetch("https://nano-gpt.com/api/v1/decisions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.NANOGPT_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    model: "typesafe/jev-1.13",
    state: {
      ticket: "I was charged twice and need this fixed before Friday.",
      customer_tier: "business",
    },
    questions: {
      route: {
        type: "choice",
        instructions: "Which team should handle this ticket?",
        criteria: {
          billing: "Payments, invoices, refunds, or duplicate charges",
          technical: "Product behavior, bugs, or integrations",
          sales: "Plans, pricing, or purchasing",
        },
      },
      urgency: {
        type: "score",
        instructions: "How urgent is the ticket?",
        criteria: [
          "No time pressure",
          "Can wait several days",
          "Needs attention within one business day",
          "Immediate action is required",
        ],
      },
      needs_human_review: {
        type: "noul",
        instructions: "Does this ticket need human review?",
        criteria: {
          true: "A person should review the case",
          false: "Automation can safely handle the case",
        },
      },
    },
    user: "customer_123",
  }),
});

if (!response.ok) throw new Error(await response.text());
const decision = await response.json();
console.log(decision.answers);

import os
import requests

response = requests.post(
    "https://nano-gpt.com/api/v1/decisions",
    headers={
        "Authorization": f"Bearer {os.environ['NANOGPT_API_KEY']}",
        "Content-Type": "application/json",
    },
    json={
        "model": "typesafe/jev-1.13",
        "state": {
            "ticket": "I was charged twice and need this fixed before Friday.",
            "customer_tier": "business",
        },
        "questions": {
            "route": {
                "type": "choice",
                "instructions": "Which team should handle this ticket?",
                "criteria": {
                    "billing": "Payments, invoices, refunds, or duplicate charges",
                    "technical": "Product behavior, bugs, or integrations",
                    "sales": "Plans, pricing, or purchasing",
                },
            },
            "urgency": {
                "type": "score",
                "instructions": "How urgent is the ticket?",
                "criteria": [
                    "No time pressure",
                    "Can wait several days",
                    "Needs attention within one business day",
                    "Immediate action is required",
                ],
            },
            "needs_human_review": {
                "type": "noul",
                "instructions": "Does this ticket need human review?",
                "criteria": {
                    "true": "A person should review the case",
                    "false": "Automation can safely handle the case",
                },
            },
        },
        "user": "customer_123",
    },
    timeout=30,
)
response.raise_for_status()
print(response.json()["answers"])

Example response

{
  "id": "decision_...",
  "model": "typesafe/jev-1.13",
  "provider": "TypeSafe",
  "answers": {
    "route": {
      "type": "choice",
      "choice": "billing",
      "confidence": 0.97,
      "probabilities": {
        "billing": 0.97,
        "technical": 0.02,
        "sales": 0.01
      }
    },
    "urgency": {
      "type": "score",
      "score": 2.63,
      "confidence": 0.81,
      "legend": {
        "0": "No time pressure",
        "1": "Can wait several days",
        "2": "Needs attention within one business day",
        "3": "Immediate action is required"
      },
      "probabilities": {
        "0": 0.01,
        "1": 0.05,
        "2": 0.24,
        "3": 0.70
      }
    },
    "needs_human_review": {
      "type": "noul",
      "noul": 0.84
    }
  },
  "usage": {
    "input_tokens": 126,
    "output_tokens": 8
  }
}

noul is the probability of the true outcome. A score can be fractional because it is the expected value across the returned score distribution.

Question types

Type	Required fields	Answer
`choice`	`instructions` and a non-empty `criteria` object	`choice`, `confidence`, and `probabilities` keyed by the supplied labels
`score`	`instructions` and 2-10 ordered `criteria` entries	Fractional `score`, `confidence`, `legend`, and `probabilities` keyed from `0`
`noul`	`instructions`; optional `criteria.true` and `criteria.false` descriptions	`noul`, a probability from `0` to `1`

instructions and criterion descriptions can be strings, non-empty JSON objects, or non-empty arrays. A choice criterion may also be null when its label is self-explanatory. The top-level state can be a string, JSON object, or JSON array. Question names become keys in answers.

Request fields

Field	Type	Required	Description
`model`	string	Yes	`typesafe/jev-1.13` or `typesafe/jev-latest`.
`state`	string, object, or array	Yes	Application state for Jev to evaluate.
`questions`	object	Yes	One or more named `choice`, `score`, or `noul` questions.
`user`	string	No	Your end-user identifier, up to 256 characters.
`session_id`	string	No	Your session identifier, up to 256 characters.
`trace`	object	No	Caller-supplied trace metadata.
`provider`	object or null	No	Native Decisions routing controls. Usually omit this field.

The native provider object can contain endpoint-level order, only, ignore, allow_fallbacks, require_parameters, max_price, zdr, and data_collection controls. These names describe native Decisions endpoints such as TypeSafe; they are not NanoGPT provider IDs. API-key provider restrictions and zero-data-retention requirements still apply.

Official TypeSafe SDK

NanoGPT exposes POST /api/v1/systemone so the official TypeSafe JavaScript and Python SDKs can call Jev without changing their request types.

// npm install @typesafe-ai/sdk
import { choice, TypeSafeClient } from "@typesafe-ai/sdk";

const client = new TypeSafeClient({
  apiKey: process.env.NANOGPT_API_KEY!,
  baseURL: "https://nano-gpt.com/api",
  defaultModel: "jev-latest",
});

const result = await client.systemOne({
  state: { ticket: "I was charged twice. Please fix this." },
  questions: {
    route: choice("Which team should handle this ticket?", {
      billing: null,
      technical: null,
      sales: null,
    }),
  },
});

console.log(result.answers.route.choice);

# pip install typesafe-sdk
import os
from typesafe_sdk import Choice, TypeSafeClient

with TypeSafeClient(
    api_key=os.environ["NANOGPT_API_KEY"],
    base_url="https://nano-gpt.com/api",
    model="jev-latest",
) as client:
    result = client.system_one(
        state={"ticket": "I was charged twice. Please fix this."},
        questions={
            "route": Choice(
                instructions="Which team should handle this ticket?",
                criteria={
                    "billing": None,
                    "technical": None,
                    "sales": None,
                },
            ),
        },
    )

print(result.choices["route"].choice)

The SDK’s System One call is supported. The SDK’s model-list method is not, because NanoGPT’s /api/v1/models response uses the NanoGPT/OpenAI-compatible model-list shape rather than TypeSafe’s model-list shape.

OpenAI and Anthropic compatibility

Use these shapes when Jev must fit into an existing OpenAI- or Anthropic-compatible client. The answer object is returned as JSON text, so parse the returned string once.

Chat Completions

curl https://nano-gpt.com/api/v1/chat/completions \
  -H "Authorization: Bearer $NANOGPT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "typesafe/jev-latest",
    "messages": [
      {"role": "user", "content": "I was charged twice. Please fix this."}
    ],
    "stream": false,
    "response_format": {
      "type": "questions",
      "questions": {
        "billing": {
          "type": "noul",
          "instructions": "Is this request about billing?"
        }
      }
    }
  }'

Parse choices[0].message.content as JSON.

Responses API

curl https://nano-gpt.com/api/v1/responses \
  -H "Authorization: Bearer $NANOGPT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "typesafe/jev-latest",
    "input": "I was charged twice. Please fix this.",
    "stream": false,
    "store": false,
    "text": {
      "format": {
        "type": "questions",
        "questions": {
          "billing": {
            "type": "noul",
            "instructions": "Is this request about billing?"
          }
        }
      }
    }
  }'

Parse output_text as JSON. The same JSON text is also available in the assistant output item.

Anthropic Messages

curl https://nano-gpt.com/api/v1/messages \
  -H "x-api-key: $NANOGPT_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "typesafe/jev-latest",
    "max_tokens": 128,
    "messages": [
      {"role": "user", "content": "I was charged twice. Please fix this."}
    ],
    "stream": false,
    "output_config": {
      "format": {
        "type": "questions",
        "questions": {
          "billing": {
            "type": "noul",
            "instructions": "Is this request about billing?"
          }
        }
      }
    }
  }'

Parse content[0].text as JSON. max_tokens is accepted for Anthropic SDK compatibility but does not change Jev’s fixed typed output.

Limitations

Jev requests are deliberately narrower than chat generation requests:

Only non-streaming text input in user messages is supported on compatibility endpoints.
System, developer, assistant, tool, image, audio, video, and file input is not supported.
Tools, sampling controls, log probabilities, and reasoning generation controls are not supported.
Output-token-limit fields are accepted where an SDK requires them, but they do not change Jev’s fixed typed output.
BYOK and accountless x402 payments are not supported.
Standard NanoGPT or X-Provider provider pins are not supported. Use the native Decisions provider object only when you need endpoint-level routing controls.

Unsupported combinations return a 400 error instead of being silently ignored.

Authorizations

Authorization

string

header

required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Body

application/json

model

enum<string>

required

Available options:

typesafe/jev-1.13,

~typesafe/jev-latest,

typesafe/jev-latest

state

required

Application state to evaluate.

questions

object

required

Show child attributes

provider

object | null

Optional native Decisions endpoint-routing controls. These are not NanoGPT provider IDs.

session_id

string

Maximum string length: 256

trace

object

user

string

Maximum string length: 256

Response

Typed decisions response

model

string

required

answers

object

required

Show child attributes

usage

object

required

Show child attributes

string

provider

string

Get Started

Endpoint Examples

API Reference

Miscellaneous

Partner

Integrations

Overview

Models

Native Decisions API

Endpoint

Example request

Example response

Question types

Request fields

Official TypeSafe SDK

OpenAI and Anthropic compatibility

Chat Completions

Responses API

Anthropic Messages

Limitations

Authorizations

Body

Response

​Overview

​Models

​Native Decisions API

​Endpoint

​Example request

​Example response

​Question types

​Request fields

​Official TypeSafe SDK

​OpenAI and Anthropic compatibility

​Chat Completions

​Responses API

​Anthropic Messages

​Limitations

Authorizations

Body

Response

Overview

Models

Native Decisions API

Endpoint

Example request

Example response

Question types

Request fields

Official TypeSafe SDK

OpenAI and Anthropic compatibility

Chat Completions

Responses API

Anthropic Messages

Limitations