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

# M300: Missing messages array

> Manifest error M300 fires when the /v1/chat/completions body has no messages array (missing, not an array, or empty). Returns HTTP 400.

## What you saw

```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
[🦚 Manifest M300] `messages` array is required.
See https://manifest.build/docs/errors/M300
```

## Why it happened

The OpenAI-compatible chat completions API requires a `messages` array with at least one entry. Manifest got a body where `messages` was missing, not an array, or empty.

## How to fix it

Send a body shaped like this:

```json theme={"theme":{"light":"github-light","dark":"github-dark"}}
{
  "model": "auto",
  "messages": [
    { "role": "user", "content": "Hello" }
  ]
}
```

The OpenAI SDK handles this for you. If you're hand-rolling the request, eyeball the JSON before posting.

## Related

* [M301: Messages array too long](/errors/M301)
* [API reference](/reference/api)
* [All error codes](/errors)