> ## Documentation Index
> Fetch the complete documentation index at: https://docs.auto.venki.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Prompt Metadata (Beta)

The basic setup described in [Quickstart](/quickstart) is the simplest way to get started and is recommended for most users.
However, it does not support prompt optimization.

It supports:

<Icon icon="check" /> Model routing, fallbacks and retries <br />
<Icon icon="check" /> Automatic model leaderboard <br />
<Icon icon="check" /> Finetuning & distillation <br />
<Icon icon="xmark" color="grey" /> Prompt optimization <br />

In order to perform prompt optimization, Auto must understand:

* What parts of a request **may** be optimized (eg: instructions to the LLM )
* What parts of a request **may not** be optimized (eg: inputs, previous chat messages)

Thus, you can provide metadata to Auto to help it understand how your request is structured.

## Marking optimizable segments

Use `markOptimizable` and `markInput` to denote the parts of your request that may be optimized. The Auto server removes these tags before submitting them to the LLM. `markOptimizable` and `markInput` are rather simple, they merely surround an input with an XML marker.

```ts theme={"system"}
const markOptimizable = (input: string) => `<_auto_optimizable>${input}</_auto_optimizable>`;
const markInput = (input: string) => `<_auto_input>${input}</_auto_input>`;
```

Here's a full example:

```typescript OpenAI SDK (.ts) theme={"system"}
const markOptimizable = (input: string) =>
  `<_auto_optimizable>${input}</_auto_optimizable>`;
const markInput = (input: string) =>
  `<_auto_input>${input}</_auto_input>`;

const messages = [
  {
    role: "system",
    // We mark this optimizable, because it's an instruction to the LLM
    content: markOptimizable("You are a helpful assistant that answers question."),
  },
  {
    role: "user",
    // We do not mark this optimizable, because it's a past chat message
    content: "How do I make a peanut butter and jelly sandwich?",
  },
  {
    role: "assistant",
    // We do not mark this optimizable, because it's a past chat message
    content: "To make a peanut butter and jelly sandwich, you need to follow these steps: 1. Spread peanut butter on one slice of bread. 2. Spread jelly on the other slice of bread. 3. Put the two slices of bread together.",
  },
  {
    role: "user",
   // This message has optimizable parts that should be changed
   // But it also has inputs that should not be changed
   content: markOptimizable(`Use the following documents to answer your question: 
    ${markInput(doc1)}
    ${markInput(doc2)}
    
    Please follow the following instructions: 
    - Be concise and to the point
    - Use the provided documents to answer the question
    - If the documents do not contain the answer, say so
    - If the answer is not clear, ask follow-up questions

    User query: ${markInput(userQuery)}`
    )
  },
]
```

If you find that you need to remove the tags from your request, eg: if you decide to send it to an LLM without using Auto,  you can use `removeMarkers` to do so.

```typescript OpenAI SDK (.ts) theme={"system"}
const markerRegex =
  /<_auto_optimizable>|<\/_auto_optimizable>|<_auto_input>|<\/_auto_input>/g;
const removePromptMarkers = (input: string) => input.replace(markerRegex, "");
```