---
title: "Create a decision"
method: POST
path: "/v1/decisions"
tags: ["Decisions"]
---

# Create a decision

`POST /v1/decisions`

## Request

- Base URL: `https://api.inceptionlabs.ai`
- URL: `https://api.inceptionlabs.ai/v1/decisions`
- Auth: HTTP bearer

Evaluate named questions against a shared state with Mercury Decide. Supports binary probability (`noul`), categorical choice, and ordinal score questions. Returns answers and token usage. Streaming is not supported.

Images: put chat-style parts such as `{"type": "image_url", "image_url": {"url": "data:image/png;base64,..."}}` anywhere in `state` or a question's `instructions` (not in `criteria`). Images must be base64 PNG, JPEG, WebP, or GIF data URLs (remote URLs are not supported), at most 10 MiB each and 16 per upstream request. The complete JSON request, including base64 encoding, is also subject to the gateway's whole-request body limit (20 MiB by default).

## Request body

- DecisionRequest
  - `model` string, required
  - `state` union, required
    - string
    - object
    - JsonValue[]
      - unknown
  - `questions` object, required

## Response `200`

Successful Response

- DecisionResponse
  - `model` string, required
  - `answers` object, required
  - `usage` DecisionUsage, required
    - `input_tokens` integer, required
    - `output_tokens` integer, required

## Other responses

- `401`: Unauthorized — missing or invalid API key.
- `402`: Payment Required — billing inactive or quota exceeded.
- `404`: Not Found — model not available for this account.
- `413`: Payload Too Large — decision request body exceeds the size limit.
- `422`: Unprocessable Entity — invalid decision request.
- `429`: Too Many Requests — rate limit exceeded.
- `500`: Internal Server Error.
- `502`: Bad Gateway — invalid response from the decision service.
- `503`: Service Unavailable — decision service is unavailable.
- `504`: Gateway Timeout — decision service timed out.

## Changes

- **2026-11-03** `9d854458fa76`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/inceptionlabs/apis/inception-api/changes/v1/decisions/post.md)

---

[API](https://skmtc.dev/inceptionlabs/apis/inception-api.md) - [All operations](https://skmtc.dev/inceptionlabs/apis/inception-api/llms.txt) - [OpenAPI document](https://skmtc.dev/inceptionlabs/apis/inception-api/revisions/9d854458fa76?raw)