# How to add a custom prompt before form input?

**URL:** <https://community.openai.com/t/how-to-add-a-custom-prompt-before-form-input/692623>\
**Category:** API\
**Tags:** gpt-35-turbo, api\
**Created:** [March 21, 2024, 11:44am UTC](https://community.openai.com/t/how-to-add-a-custom-prompt-before-form-input/692623 "2024-03-21T11:44:24Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![dvlprxcii](https://sea2.discourse-cdn.com/openai1/user_avatar/community.openai.com/dvlprxcii/32/147528_2.png) [@dvlprxcii](https://community.openai.com/u/dvlprxcii)\
**Post date:** [March 21, 2024, 11:44am UTC](https://community.openai.com/t/how-to-add-a-custom-prompt-before-form-input/692623/1 "2024-03-21T11:44:24Z")

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I followed the Vercel AI SDK guide for OpenAI step-by-step,  
I’d like to send a fixed prompt before receiving user input. How can I achieve this?

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<div class="post-metadata">

**Author:** ![Diet](https://sea2.discourse-cdn.com/openai1/user_avatar/community.openai.com/diet/32/562749_2.png) [@Diet](https://community.openai.com/u/Diet)\
**Post date:** [March 21, 2024, 11:54am UTC](https://community.openai.com/t/how-to-add-a-custom-prompt-before-form-input/692623/2 "2024-03-21T11:54:32Z")

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Welcome to the community!

I imagine there are multiple guides out there - which one did you follow specifically?

Are you talking about instruct/completion mode or chat mode?

If I’m not mistaken, vercel just makes you use the vanilla openai libraries. the docs to that are here: [https://platform.openai.com/docs/api-reference/chat/create](https://platform.openai.com/docs/api-reference/chat/create)

long story short:

for instruct, your prompt is just a string. You can edit that string before sending it off.

for chat, you have a messages array. You can intercept and edit that array before sending it off to OpenAI.

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<div class="post-metadata">

**Author:** ![dvlprxcii](https://sea2.discourse-cdn.com/openai1/user_avatar/community.openai.com/dvlprxcii/32/147528_2.png) [@dvlprxcii](https://community.openai.com/u/dvlprxcii)\
**Post date:** [March 21, 2024, 12:05pm UTC](https://community.openai.com/t/how-to-add-a-custom-prompt-before-form-input/692623/4 "2024-03-21T12:05:37Z")

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I’ve been playing around with the Vercel SDK and checking out the OpenAI API. Specifically, I’ve been trying out the chat mode feature using Vercel and OpenAI, as explained in their documentation. I’ve been tinkering with the code to see what I can do with it.

```auto
import OpenAI from 'openai';
import { OpenAIStream, StreamingTextResponse } from 'ai';

// Create an OpenAI API client
const openai = new OpenAI({
  apiKey: process.env.OPENAI_API_KEY,
});

export const runtime = 'edge';

export async function POST(req: Request) {
  const { messages } = await req.json();

  const fixedPrompt = {
    role: 'system',
    content: 'give me a TL;DR of the following text: '
  };

  // Prepend the fixed prompt to the messages array
  const modifiedMessages = [fixedPrompt, ...messages];

  // Ask OpenAI for a streaming chat completion given the modified prompt
  const response = await openai.chat.completions.create({
    model: 'gpt-3.5-turbo',
    stream: true,
    messages: modifiedMessages,
  });

  // Convert the response into a friendly text-stream
  const stream = OpenAIStream(response);
  // Respond with the stream
  return new StreamingTextResponse(stream);
}

```

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<div class="post-metadata">

**Author:** ![Diet](https://sea2.discourse-cdn.com/openai1/user_avatar/community.openai.com/diet/32/562749_2.png) [@Diet](https://community.openai.com/u/Diet)\
**Post date:** [March 21, 2024, 12:15pm UTC](https://community.openai.com/t/how-to-add-a-custom-prompt-before-form-input/692623/5 "2024-03-21T12:15:39Z")

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Ah. Well, it generally looks ok, but I guess the prompt could use some work.

If you haven’t tried yet, a good testbench to get started is the playground:

[https://platform.openai.com/playground?mode=chat](https://platform.openai.com/playground?mode=chat)

there you can manually test how well your prompt works.

And if you’re a little lost on where to start with prompting, here’s the prompting guide from openai: [https://platform.openai.com/docs/guides/prompt-engineering](https://platform.openai.com/docs/guides/prompt-engineering)  
It contains a bunch of basic tricks to help you get started.