ChatRequest class final

An immutable request to a chat model.

final request = ChatRequest(
  messages: [
    Message.system('You are a concise assistant.'),
    Message.user('What is the capital of France?'),
  ],
  temperature: 0.2,
  maxOutputTokens: 256,
);
Annotations
  • @immutable

Constructors

ChatRequest({required List<Message> messages, ToolSet? tools, ToolChoice toolChoice = ToolChoice.auto, double? temperature, double? topP, int? topK, int? maxOutputTokens, List<String> stopSequences = const <String>[], int? seed, ResponseFormat responseFormat = ResponseFormat.text, ReasoningEffort? reasoningEffort, double? frequencyPenalty, double? presencePenalty, String? user, Map<String, Object?> providerOptions = const <String, Object?>{}, Map<String, Object?> metadata = const <String, Object?>{}})
Creates a request.
ChatRequest.prompt(String prompt, {String? system, double? temperature, int? maxOutputTokens, ResponseFormat responseFormat = ResponseFormat.text})
Creates a single-turn request from a prompt.
factory

Properties

cacheKey → String
A stable fingerprint of everything that affects the answer.
no setter
frequencyPenalty → double?
Penalty for token frequency, -2 to 2.
final
hashCode → int
The hash code for this object.
no setterinherited
hasTools → bool
Whether any tools are offered.
no setter
maxOutputTokens → int?
Maximum completion tokens.
final
messages → List<Message>
The conversation, oldest first.
final
metadata → Map<String, Object?>
Application metadata, never sent to a provider.
final
presencePenalty → double?
Penalty for token presence, -2 to 2.
final
providerOptions → Map<String, Object?>
Provider-specific fields merged into the request body.
final
reasoningEffort → ReasoningEffort?
How much internal reasoning to spend.
final
requirements → Set<ModelCapabilityRequirement>
Capabilities this request requires of a model.
no setter
responseFormat → ResponseFormat
The shape the answer must take.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
seed → int?
Seed for reproducible sampling, where supported.
final
stopSequences → List<String>
Sequences that stop generation when produced.
final
temperature → double?
Sampling temperature, 0 to 2.
final
toolChoice → ToolChoice
How the model may use tools.
final
tools → ToolSet?
Tools the model may call, or null when none are offered.
final
topK → int?
Top-k sampling. Supported by Anthropic and Gemini, ignored by OpenAI.
final
topP → double?
Nucleus sampling threshold, 0 to 1.
final
user → String?
Opaque end-user identifier, forwarded for provider-side abuse detection.
final
wantsStructuredOutput → bool
Whether a structured answer was requested.
no setter

Methods

copyWith({List<Message>? messages, ToolSet? tools, ToolChoice? toolChoice, double? temperature, double? topP, int? topK, int? maxOutputTokens, List<String>? stopSequences, int? seed, ResponseFormat? responseFormat, ReasoningEffort? reasoningEffort, double? frequencyPenalty, double? presencePenalty, String? user, Map<String, Object?>? providerOptions, Map<String, Object?>? metadata}) → ChatRequest
Returns a copy with selected fields replaced.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
override
withMessages(Iterable<Message> additional) → ChatRequest
Returns a copy with additional messages appended.

Operators

operator ==(Object other) → bool
The equality operator.
inherited