Retrieval-Augmented Generation (RAG)
Definition
Retrieval-augmented generation is an AI architecture that supplements a language model's response by first retrieving relevant documents from an external knowledge base and then using those documents as context for generating an answer. In legal applications, RAG grounds AI output in actual case law, statutes, and firm documents rather than relying solely on the model's training data.
A standard large language model generates answers based entirely on patterns learned during training. RAG adds a retrieval step: before the model generates a response, a search system finds the most relevant documents from a curated corpus and injects them into the model's context. The model then generates its answer based on this retrieved evidence.
For legal work, this architecture is transformative. Instead of asking a model what it remembers about a legal topic, RAG ensures the model is looking at actual case law, statutes, or internal firm documents when formulating its response. This dramatically reduces hallucination risk and allows the system to cite specific sources that the lawyer can verify.
The quality of a RAG system depends heavily on the retrieval layer. A system that retrieves irrelevant documents will produce poor answers regardless of how capable the language model is. Legal RAG systems must handle the nuances of legal citation, distinguish between binding and persuasive authority, and understand jurisdictional relevance. The embedding models and search algorithms used for retrieval must be tuned for legal language, which differs substantially from general English.
How Irys approaches this
Irys uses a multi-stage RAG pipeline that retrieves from both public legal databases and firm-specific knowledge, ranking results by jurisdictional relevance and authority weight before generating any response.
Related terms
Semantic Search in Legal
Semantic search is a search methodology that understands the meaning and intent behind a query rather than matching exact keywords. In legal research, semantic search allows lawyers to describe a legal issue in natural language and find relevant cases, statutes, and secondary sources even when they use different terminology than the query.
AI ConceptsAI Hallucination in Legal
An AI hallucination occurs when a language model generates text that appears authoritative but is factually incorrect, such as fabricating case citations, inventing statutes, or misrepresenting holdings. In legal practice, hallucinations carry professional responsibility implications because lawyers have a duty to verify the accuracy of every authority they cite.
AI ConceptsLarge Language Model (LLM)
A large language model is a neural network trained on vast text corpora that can understand and generate human language. LLMs power the natural language capabilities of legal AI tools, enabling them to read contracts, draft documents, answer research questions, and summarize complex legal materials in plain language.
AI ConceptsAI Context Window
The context window is the maximum amount of text an AI model can process in a single interaction, measured in tokens. A larger context window allows the model to consider more documents, longer contracts, or more extensive case histories simultaneously, which directly impacts the quality and completeness of its legal analysis.
See Retrieval-Augmented Generation (RAG) in action
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