curl --request POST \
  --url https://direct.evolink.ai/v1/decisions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "gpt-6-luna-decisions",
  "input": "The package arrived with a broken screen.",
  "questions": [
    {
      "type": "predicate",
      "name": "damaged",
      "instructions": "Does the customer report a damaged item?"
    }
  ]
}
'

{
  "model": "gpt-6-luna",
  "answers": [
    {
      "type": "predicate",
      "name": "is_billing",
      "probability": 1
    },
    {
      "type": "choice",
      "name": "department",
      "choice": "billing",
      "probabilities": [
        {
          "value": "billing",
          "probability": 0.98
        },
        {
          "value": "technical",
          "probability": 0.01
        },
        {
          "value": "other",
          "probability": 0.01
        }
      ],
      "confidence": 0.97
    },
    {
      "type": "score",
      "name": "severity",
      "score": 1.34,
      "probabilities": [
        {
          "value": 0,
          "label": "Cosmetic",
          "probability": 0.04
        },
        {
          "value": 1,
          "label": "Workaround available",
          "probability": 0.58
        },
        {
          "value": 2,
          "label": "Fully blocked",
          "probability": 0.38
        }
      ],
      "confidence": 0.37
    }
  ],
  "usage": {
    "input_tokens": 426,
    "input_tokens_details": {
      "cached_tokens": 0,
      "cache_write_tokens": 0
    },
    "output_tokens": 0,
    "output_tokens_details": {
      "reasoning_tokens": 0
    },
    "total_tokens": 426
  }
}

Decisions API

GPT Decisions - Complete Parameter Reference

GPT-6 Luna Decisions (gpt-6-luna-decisions) evaluates text, images, or both and returns three types of structured answers: predicate returns the probability of “yes”, choice selects one of the supplied options, and score calculates a probability-weighted score over ordered levels
Synchronous API: all answers are returned in a single request; no streaming or task polling
The request body matches the OpenAI Decisions API: with the OpenAI SDK, point base_url to EvoLink. This endpoint also accepts the OpenAI model ID gpt-6-luna
Only input tokens are billed: output, cache reads, and cache writes are free. A minimum charge applies to each request; when a single input exceeds 272,000 tokens, the input price for the entire request is 2 times the standard rate. See Model pricing for current prices
Images must be inline base64 data URLs (data:image/...;base64,...); image URLs and file_id are not supported. Up to 128 images per request
This endpoint rejects unknown fields: do not send Chat Completions parameters such as stream, temperature, or max_tokens
Suitable for content classification, ticket routing, relevance checks, and rule-based scoring. For text generation or custom JSON structures, use the Responses API

POST

decisions

curl --request POST \
  --url https://direct.evolink.ai/v1/decisions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "gpt-6-luna-decisions",
  "input": "The package arrived with a broken screen.",
  "questions": [
    {
      "type": "predicate",
      "name": "damaged",
      "instructions": "Does the customer report a damaged item?"
    }
  ]
}
'

{
  "model": "gpt-6-luna",
  "answers": [
    {
      "type": "predicate",
      "name": "is_billing",
      "probability": 1
    },
    {
      "type": "choice",
      "name": "department",
      "choice": "billing",
      "probabilities": [
        {
          "value": "billing",
          "probability": 0.98
        },
        {
          "value": "technical",
          "probability": 0.01
        },
        {
          "value": "other",
          "probability": 0.01
        }
      ],
      "confidence": 0.97
    },
    {
      "type": "score",
      "name": "severity",
      "score": 1.34,
      "probabilities": [
        {
          "value": 0,
          "label": "Cosmetic",
          "probability": 0.04
        },
        {
          "value": 1,
          "label": "Workaround available",
          "probability": 0.58
        },
        {
          "value": 2,
          "label": "Fully blocked",
          "probability": 0.38
        }
      ],
      "confidence": 0.37
    }
  ],
  "usage": {
    "input_tokens": 426,
    "input_tokens_details": {
      "cached_tokens": 0,
      "cache_write_tokens": 0
    },
    "output_tokens": 0,
    "output_tokens_details": {
      "reasoning_tokens": 0
    },
    "total_tokens": 426
  }
}

BaseURL: The default BaseURL is https://direct.evolink.ai, which has better support for text models and long-lived connections. https://api.evolink.ai is the primary endpoint for multimodal services and serves as a fallback address for text models.

Model ID is exclusive to this endpoint: gpt-6-luna-decisions can only be used on /v1/decisions. Using it on Chat Completions, Responses, or other endpoints returns 400 model_endpoint_mismatch. For conversation or text generation, use gpt-6-luna with Chat Completions or the Responses API.

Choosing a question type

Type	Suitable questions	How to use the result
`predicate`	Yes/no questions, such as whether a message is a complaint or an image shows damage	`probability` is the probability of “yes”; set your own threshold and treat values above it as a match
`choice`	Select one of several mutually exclusive categories, such as the department to route a ticket to	`choice` is the selected option; consider human review when `confidence` is low
`score`	Evaluate ordered levels, such as issue severity	`score` is the probability-weighted level score (indices start at 0) and may be fractional

You can include multiple independent questions in one request; they share the same input. If a later question depends on an earlier answer, split them into two requests.

Difference from Chat Completions / Responses: This endpoint only accepts model, input, questions, and safety_identifier. Any additional field returns 400 unknown_parameter; images must be base64 data URLs; streaming is not supported.

Authorizations

Authorization

string

header

required

##All endpoints require Bearer Token authentication##

Get an API Key:

Visit the API Key management page to get your API Key

Add it to the request header:

Authorization: Bearer YOUR_API_KEY

Body

application/json

model

enum<string>

required

Model ID. Use gpt-6-luna-decisions; this endpoint also accepts the OpenAI model ID gpt-6-luna. Both have identical behavior and billing; usage and billing records are attributed to gpt-6-luna-decisions.

gpt-6-luna-decisions is only available on this endpoint. Using it on Chat Completions, Responses, or other endpoints returns 400 model_endpoint_mismatch.

Available options:

gpt-6-luna-decisions,

gpt-6-luna

Example:

"gpt-6-luna-decisions"

input

required

The shared basis for all decisions: a text string or an array of user messages, which can contain text and inline images.

Example:

"I was charged twice for my order."

questions

object[]

required

Questions to evaluate; at least 1 is required. Questions are independent and can mix different types; question name values must be unique within a request.

Type	Purpose	Main result
`predicate`	Check whether a condition holds	`probability`: probability that it holds (0 to 1)
`choice`	Select one of the supplied options	`choice`: the selected option
`score`	Score on ordered levels	`score`: probability-weighted level score

If a later question depends on an earlier answer, split them into two requests.

Minimum array length: 1

Option 1
Option 2
Option 3

Show child attributes

safety_identifier

string

Optional. Your own end-user identifier (an opaque string), forwarded unchanged to the model provider for abuse detection

Response

One answer per question, in the same order as the questions in the request

model

string

The model that actually performed the decisions

Example:

"gpt-6-luna"

answers

object[]

One answer per question, in the same order as the questions in the request. Use name to match the question and type to distinguish answer types

Option 1
Option 2
Option 3
Option 4

Show child attributes

usage

object

Token usage. Only input tokens are billed on this endpoint: output, cache reads, and cache writes are free. A minimum charge applies to each request; when a single input exceeds 272,000 tokens, the input price for the entire request is 2 times the standard rate. See Model pricing for current prices.

Show child attributes

Image Series

Video Series

Audio Series

Text Series

Account Management

Task Management

File Management

GPT Decisions - Complete Parameter Reference

Authorizations

Body

Response