Custom Initialization

The config.py file contains initialization code that runs once at startup, before the LLMRails instance is fully initialized. Use it to register custom providers and set up shared resources.

When to Use config.py vs actions.py

Use Case	File	Reason
Register custom LLM provider	config.py	Must happen before LLMRails initialization
Register custom embedding provider	config.py	Must happen before LLMRails initialization
Initialize database connection	config.py	Shared resource, initialized once
Validate user input	actions.py	Called during request processing
Call external API	actions.py	Called during request processing
Custom guardrail logic	actions.py	Called from Colang flows

Configuration Sections

The Init Function

Define the init() function to initialize resources and register action parameters at startup.

The Init Function

Custom LLM Providers

Register custom text completion (BaseLLM) and chat models (BaseChatModel) for use with NeMo Guardrails.

Custom LLM Providers

Custom Embedding Providers

Register custom embedding providers for vector similarity search in NeMo Guardrails.

Custom Embedding Providers

Custom Configuration Data

Pass and access custom data from config.yml in your initialization code and actions.

Custom Configuration Data

Related Topics

• Custom Actions - Define callable actions in actions.py

• Model Configuration - Configure LLM models in config.yml