Advanced Features

API reference for constrained generation and function calling in the LEAP iOS SDK

GenerationOptions

Tune generation behavior with GenerationOptions.

public struct GenerationOptions {
  public var temperature: Float?
  public var topP: Float?
  public var minP: Float?
  public var repetitionPenalty: Float?
  public var jsonSchemaConstraint: String?
  public var functionCallParser: LeapFunctionCallParserProtocol?

  public init(
    temperature: Float? = nil,
    topP: Float? = nil,
    minP: Float? = nil,
    repetitionPenalty: Float? = nil,
    jsonSchemaConstraint: String? = nil,
    functionCallParser: LeapFunctionCallParserProtocol? = LFMFunctionCallParser()
  )
}

• Leave a field as nil to fall back to the defaults packaged with the model bundle.
• functionCallParser controls how tool-call tokens are parsed. LFMFunctionCallParser (the default) handles Liquid Foundation Model Pythonic function calling. Supply HermesFunctionCallParser() for Hermes/Qwen3 formats, or set the parser to nil to receive raw tool-call text in MessageResponse.chunk.
• jsonSchemaConstraint activates constrained generation. Use setResponseFormat(type:) to populate it from a type annotated with the @Generatable macro.

extension GenerationOptions {
  public mutating func setResponseFormat<T: GeneratableType>(type: T.Type) throws {
    self.jsonSchemaConstraint = try JSONSchemaGenerator.getJSONSchema(for: type)
  }
}

var options = GenerationOptions(temperature: 0.6, topP: 0.9)
try options.setResponseFormat(type: CityFact.self)

for try await response in conversation.generateResponse(
  message: user,
  generationOptions: options
) {
  // Handle structured output
}

LiquidInferenceEngineRunner exposes advanced utilities such as getPromptTokensSize(messages:addBosToken:) for applications that need to budget tokens ahead of time. These methods are backend-specific and may be elevated to the ModelRunner protocol in a future release.

Function Calling Types

public struct LeapFunction {
  public let name: String
  public let description: String
  public let parameters: [LeapFunctionParameter]
}

public struct LeapFunctionParameter {
  public let name: String
  public let type: LeapFunctionParameterType
  public let description: String
  public let optional: Bool
}

public indirect enum LeapFunctionParameterType: Codable, Equatable {
  case string(StringType)
  case number(NumberType)
  case integer(IntegerType)
  case boolean(BooleanType)
  case array(ArrayType)
  case object(ObjectType)
  case null(NullType)
}

The parameter type wrappers (StringType, NumberType, etc.) let you attach descriptions and enumerations so that JSON schemas accurately describe your tools. See the Function Calling guide for in-depth usage patterns.