Cog is an open-source CLI and runtime for packaging machine learning models into production-ready Docker containers. It automatically generates HTTP inference servers with OpenAPI schema, handles GPU/CUDA/cuDNN compatibility, and provides a full weight management pipeline for large model artifacts. The project consists of a Go CLI (build, push, serve, predict, doctor, weights management), a Rust/PyO3 prediction server (coglet) with slot-based concurrency, a Python SDK for defining model interfaces (BaseRunner, Input, streaming), and a TypeScript playground UI. Key workflows include building OCI images from cog.yaml, pushing to registries, serving models via HTTP with SSE streaming, and managing model weights via content-addressed storage and lockfiles. The architecture is multi-language but cleanly separated, with well-defined protocols between components.