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

# Errors

> Handle stable error codes, machine-readable reasons, request paths, and provider failures.

Transformation and restoration failures are atomic: DataFog Core returns no
partially transformed result.

## Error fields

| Field                            | Meaning                                       |
| -------------------------------- | --------------------------------------------- |
| `code`                           | Stable top-level error category               |
| `reason`                         | Optional machine-readable detail              |
| `message`                        | Sanitized human-readable explanation          |
| `path`                           | Optional RFC 6901 request path                |
| `finding_index` / `findingIndex` | Optional index of an invalid supplied finding |

Error messages and metadata do not include matched PII, key material,
credentials, token payloads, or restored plaintext.

## Error codes

### Request validation

* `invalid_configuration`
* `invalid_finding`

### Key providers

* `key_provider_required`
* `key_not_found`
* `key_access_denied`
* `key_provider_unavailable`
* `invalid_key_material`
* `key_provider_error`

### Token providers and envelopes

* `token_provider_required`
* `invalid_token`
* `unsupported_token_version`
* `token_not_found`
* `token_expired`
* `token_access_denied`
* `invalid_token_material`
* `token_provider_unavailable`
* `token_provider_error`

### Capability and engine failures

* `unsupported_strategy`
* `internal_error`

## JavaScript example

```javascript theme={null}
try {
  scanAndTransform(text, config);
} catch (error) {
  if (error instanceof DataFogError) {
    console.error(error.code, error.path);
  }
}
```

## Python example

```python theme={null}
from datafog_core import DataFogConfigurationError

try:
    scan_and_transform(text, config)
except DataFogConfigurationError as error:
    print(error.code, error.reason, error.path)
```

<Tip>
  Branch on `code` and `reason`, not on the human-readable message.
</Tip>