OpenKL acts as a standardized, declarative middleware layer for LLM-to-knowledge-base retrieval.

OpenKL decouples the retrieval interface from specific database backends using declarative schemas. It translates natural language queries into structured execution plans across multiple vector and relational stores. This middleware approach abstracts the underlying storage complexity for LLM agents. However, this abstraction introduces a translation overhead that increases query latency. It also limits the use of vendor-specific database optimizations. The system relies heavily on the accuracy of its schema mapping engine to prevent retrieval failures.