Opper AI Functions API

openapi: 3.2.0
info:
  description: Schema-driven generative API that orchestrates LLM-powered workflows.
  title: Task Functions API
  version: 3.0.0
servers:
- description: Production
  url: https://api.opper.ai
- description: Local development
  url: http://localhost:8080
security:
- BearerAuth: []
tags:
- description: Schema-driven function management and execution
  name: Functions
paths:
  /v3/realtime:
    get:
      description: 'Model-driven, scriptless realtime WebSocket endpoint. Open a WS connection, send a `session.start` event with `config.model` set to an Opper realtime model id (e.g. `openai/gpt-realtime-2`); the server resolves the provider from the model registry and connects upstream. Requires a project-scoped runtime API key (server-side) OR an ephemeral ticket minted via `POST /v3/realtime-sessions` (browser-side, passed as `?ticket=` or `Sec-WebSocket-Protocol: opper-ticket.`). Sessions are bounded by per-project concurrency, max duration, and idle timeout caps; billing flushes every 30 seconds with synchronous balance enforcement.'
      operationId: realtimeAdhocWebSocket
      responses:
        '101':
          description: Switching Protocols – WebSocket connection established
        '400':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Bad request
        '401':
          description: Unauthorized - missing or invalid API key
        '500':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Internal server error
      summary: Realtime WebSocket (ad-hoc)
      tags:
      - Functions
  /v3/realtime-sessions:
    post:
      description: Server-to-server endpoint that mints a short-lived, single-use ticket the browser uses to open a `/v3/realtime` WebSocket. Browsers cannot set an `Authorization` header on a WebSocket constructor, so the customer's backend authenticates with its normal API key here and returns the ticket to the browser. Fields in `config` are bound to the ticket and cannot be overridden by the browser at session.start — pre-bind `model` at minimum so a leaked ticket can't be redirected to a more expensive model. To lock a field to its zero value (e.g. force `output_transcription` off), include the field name in `locked_fields`; non-listed zero values stay open for the browser to fill in.
      operationId: createRealtimeSession
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/RealtimeSessionRequest'
        required: true
      responses:
        '200':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RealtimeSessionResponse'
          description: Successful response
        '400':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Bad request
        '401':
          description: Unauthorized - missing or invalid API key
        '500':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Internal server error
      summary: Mint realtime ephemeral ticket
      tags:
      - Functions
  /v3/realtime/{name}:
    get:
      description: WebSocket endpoint for realtime voice agent communication. The client must send an HTTP Upgrade request; a successful connection returns 101 Switching Protocols. OpenAPI 3.1 does not natively support WebSocket, so this is documented descriptively.
      operationId: realtimeWebSocket
      parameters:
      - description: Function name
        in: path
        name: name
        required: true
        schema:
          type: string
      responses:
        '101':
          description: Switching Protocols – WebSocket connection established
        '400':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Bad request
        '401':
          description: Unauthorized - missing or invalid API key
        '500':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
          description: Internal server error
      summary: Realtime WebSocket
      tags:
      - Functions
components:
  schemas:
    ErrorResponse:
      properties:
        error:
          properties:
            code:
              type: string
            details:
              description: Any value
            message:
              type: string
          required:
          - code
          - message
          type: object
        meta:
          type: object
      required:
      - error
      type: object
    RealtimeSessionRequest:
      properties:
        config:
          properties:
            input_audio_format:
              type: string
            input_transcription:
              type: boolean
            input_transcription_model:
              type: string
            instructions:
              type: string
            modalities:
              items:
                type: string
              type: array
            model:
              type: string
            output_audio_format:
              type: string
            output_transcription:
              type: boolean
            reasoning_effort:
              type: string
            temperature:
              type: number
            tools:
              items:
                properties:
                  description:
                    type: string
                  name:
                    type: string
                  parameters:
                    type: object
                required:
                - name
                type: object
              type: array
            transcription_custom_vocabulary:
              items:
                type: string
              type: array
            transcription_language_codes:
              items:
                type: string
              type: array
            transcription_mode:
              type: string
            translation_echo_target_language:
              type: boolean
            translation_target_language:
              type: string
            turn_detection:
              properties:
                eagerness:
                  type: string
                prefix_padding_ms:
                  type: integer
                silence_duration_ms:
                  type: integer
                threshold:
                  type: number
                type:
                  type: string
              required:
              - type
              type: object
            voice:
              type: string
          type: object
        locked_fields:
          items:
            type: string
          type: array
        ttl_seconds:
          type: integer
      type: object
    RealtimeSessionResponse:
      properties:
        client_secret:
          type: string
        expires_at:
          format: date-time
          type: string
        ws_url:
          type: string
      required:
      - client_secret
      - expires_at
      type: object
  securitySchemes:
    BearerAuth:
      bearerFormat: API Key
      description: API key authentication. Pass your API key as a Bearer token.
      scheme: bearer
      type: http
    MCPBearer:
      description: Delegated user OAuth access token for the Opper MCP resource. Obtain through advertised OAuth authorization; runtime and management service keys are not accepted.
      scheme: bearer
      type: http
    ManagementBearer:
      bearerFormat: Management API Key
      description: Management API authentication. Pass an `op-mak-…` management token as a Bearer token. Runtime `op-…` API keys are rejected with 403 — they belong on the data-plane endpoints. Mint a management key from the platform UI under Settings → API keys.
      scheme: bearer
      type: http