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

# Proxy Errors

> Common proxy error shapes and how to respond.

Kylon proxy endpoints return provider-compatible errors where practical. Shared proxy errors use a small JSON shape.

## Missing or invalid API key

```json theme={null}
{
  "error": "unauthorized",
  "message": "Missing API key"
}
```

or:

```json theme={null}
{
  "error": "unauthorized",
  "message": "Invalid API key"
}
```

Fix: pass a valid Kylon key using `x-api-key` or `Authorization: Bearer`.

## Missing provider access

```json theme={null}
{
  "error": "unauthorized",
  "message": "No access to the required skill. Please check the agent skill settings."
}
```

Fix: enable the required provider capability for the agent, or call an endpoint the agent is allowed to use.

## Missing request fields

Some endpoints validate required fields directly:

```json theme={null}
{
  "error": "Missing required fields: toolkit, method, url"
}
```

Fix: check the endpoint documentation and include the required fields.

## Payment required

```json theme={null}
{
  "error": "payment_required",
  "code": "payment_required",
  "message": "Workspace credits are unavailable or exhausted",
  "details": {}
}
```

Fix: add credits, reduce usage, or retry after a script-level limit resets.

## Provider errors

Buffered provider proxy routes generally return:

```json theme={null}
{
  "error": "proxy_error",
  "message": "Provider error message"
}
```

Model-compatible routes may return provider-shaped errors instead, such as OpenAI-style or Anthropic-style error objects.

## Retry guidance

| Status | Recommended action                                            |
| ------ | ------------------------------------------------------------- |
| `400`  | Fix the request shape or missing fields                       |
| `401`  | Check API key and provider access                             |
| `402`  | Check credits or script-level credit policy                   |
| `429`  | Back off and retry with jitter                                |
| `499`  | Client disconnected; retry if still needed                    |
| `5xx`  | Retry with exponential backoff if the operation is idempotent |