Nemo engine

Default NeMo Guardrails engine implementation.

NemoGuardrailEngine(config=None)

Bases: GuardrailEngine

Default engine that keeps current NeMo Guardrails behavior.

This engine implements the GuardrailEngine protocol to provide NeMo Guardrails functionality for content safety checking.

Attributes:

Name	Type	Description
config	NemoGuardrailEngineConfig	Engine configuration specifying what content types to check.
rails	LLMRails | None	LLMRails instance.

Initializes a new instance of the NemoGuardrailEngine class.

Parameters:

Name	Type	Description	Default
config	NemoGuardrailEngineConfig | None	NemoGuardrailEngineConfig with both base and NeMo-specific settings.	None

check_input(content, **kwargs) async

Check input content for safety violations.

This method implements NeMo Guardrails checking for user input such as query content, context, or prompts before sending to LLM.

Parameters:

Name	Type	Description	Default
content	str	The input text to evaluate for safety.	required
**kwargs	Any	Additional engine-specific parameters.	{}

Returns:

Name	Type	Description
GuardrailResult	GuardrailResult	GuardrailResult indicating if content is safe, with reason if unsafe.

Raises:

Type	Description
RuntimeError	If the guardrail engine is not initialized.

check_output(content, **kwargs) async

Check output content for safety violations.

This method implements NeMo Guardrails checking for system output such as LLM responses, generated text, or static messages before showing to users.

Parameters:

Name	Type	Description	Default
content	str	The output text to evaluate for safety.	required
**kwargs	Any	Additional engine-specific parameters.	{}

Returns:

Name	Type	Description
GuardrailResult	GuardrailResult	GuardrailResult indicating if content is safe, with reason if unsafe.

Raises:

Type	Description
RuntimeError	If the guardrail engine is not initialized.

NemoGuardrailEngineConfig

Bases: BaseGuardrailEngineConfig

NeMo-specific configuration that extends base guardrail config.

This config inherits the basic guardrail_mode from BaseGuardrailEngineConfig and adds NeMo-specific settings for advanced guardrail functionality.

Attributes:

Name	Type	Description
lm_invoker	BaseLMInvoker | None	Invoker used by the NeMo adapter.
config_dict	dict[str, Any] | None	Legacy NeMo guardrails config dict (deprecated).
denial_phrases	list[str] | None	Phrases that indicate blocked content.
topic_safety_mode	TopicSafetyMode | str | None	Topic safety mode.
allowed_topics	list[str] | None	List of allowed topics for responses.
denied_topics	list[str] | None	List of denied topics for responses.
include_core_restrictions	bool | None	Whether to include core safety restrictions.
core_restriction_categories	list[str] | None	List of enabled core restriction categories.
colang_config	str | None	Optional Colang configuration string.
nemo_kwargs	dict[str, Any] | None	NeMo-specific kwargs.

from_model_config(model_id, credentials=None, config=None, **kwargs) classmethod

Create a NemoGuardrailEngineConfig from a model configuration.

Parameters:

Name	Type	Description	Default
model_id	str | ModelId	The model ID.	required
credentials	str | dict[str, Any] | None	The credentials for the model.	None
config	dict[str, Any] | None	The model configuration.	None
**kwargs	Any	Additional kwargs to pass to the constructor.	{}

Returns:

Name	Type	Description
NemoGuardrailEngineConfig	NemoGuardrailEngineConfig	The created NemoGuardrailEngineConfig.

init_guardrails_provider_registration()

Register global NeMo Guardrails chat provider once.

This avoids redundant registration per preset/component. Safe to call once during process initialization.

Returns:

Name	Type	Description
bool	bool	True if registration succeeded, False otherwise.