JustVugg/colibri

Run frontier MoE models on hardware you already own — pure C, zero deps, experts streamed from disk. Tiny engine, immense model. 🐦

colibri is a tiny, pure-C engine that runs very large open-weights AI models (mixture-of-experts language models, a vision model, and decision models) on ordinary computers—no GPU required, though it can use one when available. Its core trick is that a huge model like GLM-5.2 (744B parameters) only activates a small fraction of its weights for each token, so colibri keeps the always-needed "dense" part in RAM and streams the rarely-used "expert" weights from disk on demand. This lets models that would normally need hundreds of GB of VRAM run on a machine with 8–16 GB of RAM and a fast NVMe drive.

How it works

  • Mixture-of-experts (MoE) models have many parallel "expert" sub-networks; only a few are used per token. colibri exploits this sparsity.
  • The dense layers (attention, shared experts, embeddings) stay resident in RAM. Routed experts are read from disk through a cache that learns which ones your conversations use.
  • If a GPU is present, it can hold the hottest experts and dense layers, accelerating inference. The engine supports Vulkan (any GPU with a Vulkan 1.2 driver) and CUDA (NVIDIA cards on Linux/Windows).
  • The engine is written in C, one file per model family, and is designed to be auditable and measurable—an open research platform.

What it runs

  • Language models: GLM-5.2/5.3, DeepSeek V4 Flash, Kimi K3 (2.8T params), Qwen3.6, Qwen3-Coder, OLMoE, and more.
  • Image generation: Qwen-Image-2.1.
  • Decision models (fast, single-answer classifiers): Laya, GLiNER2.5-Decide, Clef.
  • All models are open-weights and downloaded from Hugging Face.

Getting started

  • One-step installer for Windows, Linux, macOS: download, run START-HERE.bat or ./start-here.sh, answer one question (which model), and it detects your hardware, recommends a fitting model, builds/downloads the engine, downloads the model, and starts a local server with a browser dashboard.
  • The server exposes OpenAI- and Anthropic-compatible APIs, so you can plug it into existing tools.
  • An MCP server (coli mcp) lets AI coding assistants install and manage colibri programmatically.

Key features

  • Streaming from disk: models much larger than RAM run by reading experts on demand.
  • GPU acceleration: optional Vulkan or CUDA builds; the setup automatically picks the best backend for your hardware.
  • Transparent and measurable: every optimization is backed by reproducible benchmarks; the dashboard shows expert activation in real time.
  • Resumable downloads and a robust setup that handles missing packages, GPU driver issues, and disk space problems.

Hardware requirements

  • Minimum 8 GB RAM (16 GB+ recommended), 22 GB free disk for the smallest model, internet connection. A GPU is optional.
  • For large models, a fast NVMe SSD is crucial—disk speed limits token generation.

Why it matters colibri democratizes access to frontier-scale open models by making them run on hardware people already own, without sacrificing fidelity—it never silently changes model precision or routing semantics. It's a practical tool and a research platform for efficient MoE inference.

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