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.bator./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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