Composition

This notebook goes over how to compose multiple prompts together. This can be useful when you want to reuse parts of prompts. This can be done with a PipelinePrompt. A PipelinePrompt consists of two main parts:

• Final prompt: This is the final prompt that is returned
• Pipeline prompts: This is a list of tuples, consisting of a string name and a prompt template. Each prompt template will be formatted and then passed to future prompt templates as a variable with the same name.

import {
  PromptTemplate,
  PipelinePromptTemplate,
} from "@langchain/core/prompts";

const fullPrompt = PromptTemplate.fromTemplate(`{introduction}

{example}

{start}`);

const introductionPrompt = PromptTemplate.fromTemplate(
  `You are impersonating {person}.`
);

const examplePrompt =
  PromptTemplate.fromTemplate(`Here's an example of an interaction:
Q: {example_q}
A: {example_a}`);

const startPrompt = PromptTemplate.fromTemplate(`Now, do this for real!
Q: {input}
A:`);

const composedPrompt = new PipelinePromptTemplate({
  pipelinePrompts: [
    {
      name: "introduction",
      prompt: introductionPrompt,
    },
    {
      name: "example",
      prompt: examplePrompt,
    },
    {
      name: "start",
      prompt: startPrompt,
    },
  ],
  finalPrompt: fullPrompt,
});

const formattedPrompt = await composedPrompt.format({
  person: "Elon Musk",
  example_q: `What's your favorite car?`,
  example_a: "Telsa",
  input: `What's your favorite social media site?`,
});

console.log(formattedPrompt);

/*
  You are impersonating Elon Musk.

  Here's an example of an interaction:
  Q: What's your favorite car?
  A: Telsa

  Now, do this for real!
  Q: What's your favorite social media site?
  A:
*/

API Reference:

• PromptTemplate from @langchain/core/prompts
• PipelinePromptTemplate from @langchain/core/prompts