Windows ML API

openapi: 3.1.0
info:
  title: Microsoft Windows 10 Windows ML API
  description: >-
    API for integrating trained machine learning models into Windows applications
    using the ONNX format. Based on the Windows.AI.MachineLearning namespace,
    Windows ML evaluates models locally on the device using hardware acceleration
    with DirectX 12. Key classes include LearningModel, LearningModelSession,
    LearningModelBinding, and LearningModelEvaluationResult.
  version: 1.0.0
  contact:
    name: Microsoft Developer Support
    url: https://learn.microsoft.com/en-us/windows/ai/windows-ml/
  license:
    name: Microsoft Software License
    url: https://www.microsoft.com/en-us/legal/terms-of-use
externalDocs:
  description: Windows ML API Reference
  url: https://learn.microsoft.com/en-us/windows/ai/windows-ml/api-reference
servers:
  - url: https://api.windows.com
    description: Windows Platform API
paths:
  /ml/models:
    get:
      operationId: listMLModels
      summary: Microsoft Windows 10 List loaded ML models
      description: >-
        Retrieves the list of currently loaded machine learning models. Each
        model is loaded via the LearningModel class from ONNX format files and
        provides metadata including the model author, name, domain, description,
        version, and input/output features.
      tags:
        - Models
      responses:
        '200':
          description: Successful retrieval of loaded models
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/LearningModel'
    post:
      operationId: loadMLModel
      summary: Microsoft Windows 10 Load a machine learning model
      description: >-
        Loads an ONNX machine learning model using LearningModel.LoadFromFilePath
        or LearningModel.LoadFromStream. The loaded model can then be used to
        create evaluation sessions. Supports ONNX versions 1.2 and 1.3.
      tags:
        - Models
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/LoadModelRequest'
      responses:
        '201':
          description: Model loaded successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/LearningModel'
        '400':
          description: Invalid model file or format
        '415':
          description: Unsupported model format (must be ONNX)
  /ml/models/{modelId}:
    get:
      operationId: getMLModel
      summary: Microsoft Windows 10 Get model details
      description: >-
        Retrieves detailed information about a loaded model including its
        input features (ILearningModelFeatureDescriptor), output features,
        metadata properties, and device capabilities.
      tags:
        - Models
      parameters:
        - name: modelId
          in: path
          required: true
          description: Unique identifier for the loaded model
          schema:
            type: string
      responses:
        '200':
          description: Successful retrieval of model details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/LearningModelDetail'
        '404':
          description: Model not found
    delete:
      operationId: unloadMLModel
      summary: Microsoft Windows 10 Unload a machine learning model
      description: >-
        Unloads a machine learning model by calling LearningModel.Close,
        releasing all associated resources and terminating any active sessions.
      tags:
        - Models
      parameters:
        - name: modelId
          in: path
          required: true
          description: Unique identifier for the model
          schema:
            type: string
      responses:
        '204':
          description: Model unloaded successfully
        '404':
          description: Model not found
  /ml/sessions:
    post:
      operationId: createMLSession
      summary: Microsoft Windows 10 Create an evaluation session
      description: >-
        Creates a LearningModelSession for evaluating a loaded model. The session
        binds the model to a LearningModelDevice (CPU, DirectX, or
        DirectXHighPerformance) for hardware-accelerated inference.
      tags:
        - Sessions
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CreateSessionRequest'
      responses:
        '201':
          description: Session created successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/LearningModelSession'
        '400':
          description: Invalid session configuration
        '404':
          description: Model not found
  /ml/sessions/{sessionId}/evaluate:
    post:
      operationId: evaluateMLModel
      summary: Microsoft Windows 10 Evaluate model with input data
      description: >-
        Evaluates the model with bound input data using LearningModelSession.Evaluate.
        Input features are bound via a LearningModelBinding, and results are
        returned as a LearningModelEvaluationResult containing output tensors,
        maps, sequences, or images.
      tags:
        - Evaluation
      parameters:
        - name: sessionId
          in: path
          required: true
          description: Unique identifier for the evaluation session
          schema:
            type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/EvaluationRequest'
      responses:
        '200':
          description: Evaluation completed successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/EvaluationResult'
        '400':
          description: Invalid input bindings
        '404':
          description: Session not found
  /ml/devices:
    get:
      operationId: listMLDevices
      summary: Microsoft Windows 10 List available ML devices
      description: >-
        Retrieves the list of available LearningModelDevice options for
        model evaluation, including CPU, DirectX GPU, and DirectXHighPerformance
        targets.
      tags:
        - Devices
      responses:
        '200':
          description: Successful retrieval of available devices
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/LearningModelDevice'
components:
  schemas:
    LearningModel:
      type: object
      description: A loaded ONNX machine learning model (LearningModel class)
      properties:
        id:
          type: string
          description: Unique model identifier
        name:
          type: string
          description: Model name from metadata
        author:
          type: string
          description: Model author from metadata
        domain:
          type: string
          description: Model domain from metadata
        description:
          type: string
          description: Model description from metadata
        version:
          type: integer
          description: Model version
        inputFeatureCount:
          type: integer
          description: Number of input features
        outputFeatureCount:
          type: integer
          description: Number of output features
      required:
        - id
        - name
    LearningModelDetail:
      type: object
      description: Detailed model information
      properties:
        id:
          type: string
        name:
          type: string
        author:
          type: string
        domain:
          type: string
        description:
          type: string
        version:
          type: integer
        inputFeatures:
          type: array
          items:
            $ref: '#/components/schemas/FeatureDescriptor'
        outputFeatures:
          type: array
          items:
            $ref: '#/components/schemas/FeatureDescriptor'
        metadata:
          type: object
          additionalProperties:
            type: string
          description: Key-value metadata from the ONNX model
    FeatureDescriptor:
      type: object
      description: Describes an input or output feature of a model (ILearningModelFeatureDescriptor)
      properties:
        name:
          type: string
          description: Feature name
        description:
          type: string
          description: Feature description
        kind:
          type: string
          enum:
            - Tensor
            - Sequence
            - Map
            - Image
          description: The kind of feature (TensorFeatureDescriptor, ImageFeatureDescriptor, etc.)
        isRequired:
          type: boolean
          description: Whether the feature is required
        shape:
          type: array
          items:
            type: integer
          description: Tensor shape dimensions (for tensor features)
        tensorDataType:
          type: string
          enum:
            - Float
            - Float16
            - Double
            - Int8
            - UInt8
            - Int16
            - UInt16
            - Int32
            - UInt32
            - Int64
            - UInt64
            - String
            - Boolean
          description: Data type for tensor features
      required:
        - name
        - kind
    LoadModelRequest:
      type: object
      properties:
        filePath:
          type: string
          description: Path to the ONNX model file
        modelFormat:
          type: string
          enum:
            - ONNX
          description: Model format (currently only ONNX supported)
          default: ONNX
      required:
        - filePath
    CreateSessionRequest:
      type: object
      properties:
        modelId:
          type: string
          description: ID of the loaded model
        deviceKind:
          type: string
          enum:
            - Default
            - Cpu
            - DirectX
            - DirectXHighPerformance
            - DirectXMinPower
          description: The device to use for evaluation (maps to LearningModelDeviceKind)
          default: Default
      required:
        - modelId
    LearningModelSession:
      type: object
      description: An evaluation session (LearningModelSession class)
      properties:
        id:
          type: string
          description: Session identifier
        modelId:
          type: string
          description: Associated model identifier
        device:
          $ref: '#/components/schemas/LearningModelDevice'
    EvaluationRequest:
      type: object
      description: Input bindings for model evaluation
      properties:
        correlationId:
          type: string
          description: Correlation ID for tracking the evaluation
        bindings:
          type: object
          additionalProperties:
            type: object
          description: Map of feature names to their input values
      required:
        - bindings
    EvaluationResult:
      type: object
      description: Result of a model evaluation (LearningModelEvaluationResult)
      properties:
        correlationId:
          type: string
          description: Correlation ID from the request
        succeeded:
          type: boolean
          description: Whether evaluation succeeded
        errorStatus:
          type: integer
          description: Error code if evaluation failed
        outputs:
          type: object
          additionalProperties:
            type: object
          description: Map of output feature names to their values
    LearningModelDevice:
      type: object
      description: A device for model evaluation (LearningModelDevice class)
      properties:
        kind:
          type: string
          enum:
            - Default
            - Cpu
            - DirectX
            - DirectXHighPerformance
            - DirectXMinPower
          description: Device kind
        adapterId:
          type: string
          description: GPU adapter ID (for DirectX devices)
        name:
          type: string
          description: Device name
tags:
  - name: Devices
  - name: Evaluation
  - name: Models
  - name: Sessions