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# LanguageModelSession.GenerationError

An error that may occur while generating a response.

```
enum GenerationError
```

## Topics

### Generation errors

[`LanguageModelSession.GenerationError.assetsUnavailable(_:)`](/documentation/FoundationModels/LanguageModelSession/GenerationError/assetsUnavailable(_:))

An error that indicates the assets required for the session are unavailable.

[`LanguageModelSession.GenerationError.decodingFailure(_:)`](/documentation/FoundationModels/LanguageModelSession/GenerationError/decodingFailure(_:))

An error that indicates the session failed to deserialize a valid generable type from model output.

[`LanguageModelSession.GenerationError.exceededContextWindowSize(_:)`](/documentation/FoundationModels/LanguageModelSession/GenerationError/exceededContextWindowSize(_:))

An error that signals the session reached its context window size limit.

[`LanguageModelSession.GenerationError.guardrailViolation(_:)`](/documentation/FoundationModels/LanguageModelSession/GenerationError/guardrailViolation(_:))

An error that indicates the system’s safety guardrails are triggered by content in a
prompt or the response generated by the model.

[`LanguageModelSession.GenerationError.rateLimited(_:)`](/documentation/FoundationModels/LanguageModelSession/GenerationError/rateLimited(_:))

An error that indicates your session has been rate limited.

[`LanguageModelSession.GenerationError.refusal(_:_:)`](/documentation/FoundationModels/LanguageModelSession/GenerationError/refusal(_:_:))

An error indicating that the model refused to answer.

[`LanguageModelSession.GenerationError.concurrentRequests(_:)`](/documentation/FoundationModels/LanguageModelSession/GenerationError/concurrentRequests(_:))

An error that happens if you attempt to make a session respond to a
second prompt while it’s still responding to the first one.

[`LanguageModelSession.GenerationError.unsupportedGuide(_:)`](/documentation/FoundationModels/LanguageModelSession/GenerationError/unsupportedGuide(_:))

An error that indicates a generation guide with an unsupported pattern was used.

[`LanguageModelSession.GenerationError.unsupportedLanguageOrLocale(_:)`](/documentation/FoundationModels/LanguageModelSession/GenerationError/unsupportedLanguageOrLocale(_:))

An error that indicates an error that occurs if the model is prompted to respond in a language
that it does not support.

[`Context`](/documentation/FoundationModels/LanguageModelSession/GenerationError/Context)

The context in which the error occurred.

[`Refusal`](/documentation/FoundationModels/LanguageModelSession/GenerationError/Refusal)

A refusal produced by a language model.

### Getting the error description

[`errorDescription`](/documentation/FoundationModels/LanguageModelSession/GenerationError/errorDescription)

A string representation of the error description.

### Getting the failure reason

[`failureReason`](/documentation/FoundationModels/LanguageModelSession/GenerationError/failureReason)

A string representation of the failure reason.

### Getting the recovery suggestion

[`recoverySuggestion`](/documentation/FoundationModels/LanguageModelSession/GenerationError/recoverySuggestion)

A string representation of the recovery suggestion.

## Relationships

### Conforms To

[`LocalizedError`](/documentation/Foundation/LocalizedError)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`Error`](/documentation/Swift/Error)

[`Sendable`](/documentation/Swift/Sendable)

---

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