Output Parsers

info

Conceptual Guide

Language models output text. But many times you may want to get more structured information than just text back. This is where output parsers come in.

Output parsers are structs that help structure language model responses. There are three main methods an output parser must implement:

// OutputParser is an interface for parsing the output of an LLM call.
type OutputParser[T any] interface {
    // Parse parses the output of an LLM call.
    Parse(text string) (T, error)
    // ParseWithPrompt parses the output of an LLM call with the prompt used.
    ParseWithPrompt(text string, prompt PromptValue) (T, error)
    // GetFormatInstructions returns a string describing the format of the output.
    GetFormatInstructions() string
    // Type returns the string type key uniquely identifying this class of parser
    Type() string
}