KoboldCPP is a local large language model inference engine and GGUF model runner designed to execute quantized models on personal hardware. It functions as a multimodal AI server and API gateway, providing OpenAI-compatible endpoints that allow third-party clients to interact with locally hosted models.
The project distinguishes itself as an AI storytelling backend, featuring dedicated tools for long-form narrative management through persistent memory, world lore tracking, and character state management. It further extends its capabilities as a multimodal server capable of processing text, images, and audio using vision projectors and speech synthesis.
The system includes broad support for hardware acceleration via GPU-layer offloading and multi-GPU tensor splitting to handle large models. It incorporates advanced output control through grammar constraints and phrase banning, as well as grounded retrieval capabilities that connect models to local documents and web search.
The core runtime is implemented in C++ for high-performance memory management and hardware-level optimization.