ToolRegistry: A Protocol-Agnostic Tool Management Library for Function-Calling LLMs

Large Language Model (LLM) applications are increasingly relying on external tools to extend their capabilities beyond text generation. However, current tool integration approaches suffer from fragmentation, protocol limitations, and implementation complexity, leading to substantial development overhead. This paper presents ToolRegistry, a protocol-agnostic tool management system that has evolved from a single library into a modular three-package ecosystem: a core registry for tool management and execution, a server package providing protocol adapters (MCP, OpenAPI) and routing, and a hub package offering curated, production-tested tool implementations. Beyond the original contributions of unified registration, automated schema generation, and dual-mode concurrent execution, the ecosystem now includes an independent MCP client supporting four transport mechanisms, a web-based admin panel for runtime management, an event system for change propagation, and fine-grained tool lifecycle control. Our evaluation demonstrates that ToolRegistry achieves 60-80% reduction in tool integration code, up to 3.1x performance improvements through concurrent execution, and broad compatibility with OpenAI function calling standards. Real-world case studies show significant improvements in development efficiency and code maintainability across diverse integration scenarios. ToolRegistry is open-source and available atthis https URL, with comprehensive documentation atthis https URL.