> ## Documentation Index
> Fetch the complete documentation index at: https://docs.zerogpu.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# gpt-5.6-luna

> Model details for gpt-5.6-luna. Cost-optimized generation with adjustable reasoning effort and a 272K-token context window.

> OpenAI's GPT-5.6 Luna is the cost-optimized model of the GPT-5.6 family, served on ZeroGPU for cost-sensitive, high-volume workloads. It supports adjustable reasoning effort, function calling, and structured outputs across a 272,000-token context window.

**References:** [Terms](https://openai.com/policies/services-agreement/) • [Privacy](https://zerogpu.ai/privacy-policy)


## OpenAPI

````yaml api-reference/openapi/playgrounds/gpt-5_6-luna.openapi.json POST /responses
openapi: 3.1.0
info:
  title: gpt-5.6-luna playground
  version: '1.0'
  description: >-
    Interactive playground for **gpt-5.6-luna**.

    Model is always `gpt-5.6-luna` on this page (shown in the form, not
    editable).

    Use the **request example** selector to switch use cases (JSON, NER, PII,
    etc.).

    Authentication: `x-api-key` (required) and `x-project-id` (optional).
servers:
  - url: https://api.zerogpu.ai/v1
    description: Production
security:
  - ApiKey: []
paths:
  /responses:
    post:
      tags:
        - gpt-5.6-luna
      summary: 'gpt-5.6-luna: Responses'
      operationId: createResponse_gpt-5_6-luna
      parameters:
        - name: x-project-id
          in: header
          required: false
          schema:
            type: string
          description: >-
            Optional project identifier. Scopes the request to a specific
            project when provided.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              allOf:
                - $ref: '#/components/schemas/CreateResponseRequest'
                - type: object
                  properties:
                    model:
                      type: string
                      const: gpt-5.6-luna
                      default: gpt-5.6-luna
                      example: gpt-5.6-luna
                      description: >-
                        Model identifier (fixed for this playground). Use
                        request examples to change use cases.
            examples:
              default:
                summary: Default
                value:
                  input: Hello!
                  model: gpt-5.6-luna
      responses:
        '200':
          description: Success
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Response'
        '400':
          description: Bad request
        '401':
          description: Unauthorized
        '403':
          description: Forbidden
        '420':
          description: Insufficient quota
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '500':
          description: Internal server error
components:
  schemas:
    CreateResponseRequest:
      type: object
      required:
        - model
        - input
      properties:
        model:
          type: string
          const: gpt-5.6-luna
          default: gpt-5.6-luna
          example: gpt-5.6-luna
          description: >-
            Model identifier (fixed for this playground). Use request examples
            to change use cases.
        input:
          type: string
          minLength: 1
          format: textarea
          maxLength: 131072
          description: Multi-line text or document content to send to the model.
        instructions:
          type: string
        max_tokens:
          type: integer
          minimum: 1
          example: 800
          description: Maximum number of tokens to generate in the response.
        metadata:
          type: object
          additionalProperties: true
    Response:
      type: object
      additionalProperties: true
    ErrorResponse:
      type: object
      additionalProperties: true
  securitySchemes:
    ApiKey:
      type: apiKey
      in: header
      name: x-api-key

````