promptLength method

@override Future<int?> promptLength(List<Document> docs, { InputValues inputs = const {}, })

Returns the prompt length (number of tokens) given the documents passed in.

This can be used by a caller to determine whether passing in a list of documents would exceed a certain prompt length. This useful when trying to ensure that the size of a prompt remains below a certain context limit.

• docs is the list of documents to combine.
• inputs is a map of other inputs to use in the combination.

Returns null if the combine method doesn't depend on the prompt length. Otherwise, the length of the prompt in tokens.

Implementation

@override
Future<int?> promptLength(
  final List<Document> docs, {
  final InputValues inputs = const {},
}) {
  final llmInputs = _getInputs(docs, inputs);
  final prompt = llmChain.prompt.formatPrompt(llmInputs);
  return llmChain.llm.countTokens(prompt);
}