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

# Invalid expand

> An `expand` value is not a relation this route can expand.

This page is the resolution target of the RFC 9457 `type` URI on every `invalid_expand` problem body: `https://docs.get-exo.com/errors/invalid_expand`.

**HTTP status: `422` Unprocessable Content**.

```json theme={"theme":{"light":"github-light-default","dark":"github-dark-default"}}
{
  "type": "https://docs.get-exo.com/errors/invalid_expand",
  "title": "Invalid expand",
  "status": 422,
  "detail": "Unknown expand relation(s): sources.body. Valid values: sources.content.",
  "code": "invalid_expand",
  "requestId": "req_9f2c41ab7d0e5c18",
  "suggestedAction": "Request only supported relations: sources.content. Omit expand entirely to get the lean response.",
  "errors": [
    {
      "pointer": "#/expand",
      "field": "expand",
      "code": "unknown_expand_relation",
      "message": "'sources.body' is not an expandable relation on this route."
    }
  ]
}
```

## Why it happens

Responses are lean by default and grow only when you ask. Each route publishes its own set of expandable relations, and an unknown name fails loudly rather than being ignored.

`POST /v1/retrieve` supports one relation: `sources.content`, which replaces the 280-character snippet with the full stored text.

## How to fix it

* Read the valid values out of `detail` and `suggestedAction`. Both list exactly what the route supports.
* Omit `expand` to get the lean response.

## Related

* [`validation_error`](/errors/validation_error)
* [Errors](/platform/errors) for the envelope and the full catalogue