GR-MCP is a modern, extensible Machine Control Protocol (MCP) server for GNURadio that enables programmatic, automated, and AI-driven creation of GNURadio flowgraphs. Designed for seamless integration with Large Language Models (LLMs), automation frameworks, and custom clients, it empowers users to generate .grc files and control SDR workflows at scale. The server exposes a robust MCP API and supports building, editing, and saving flowgraphs from code or automation, making it easy to integrate GNURadio development into automated pipelines. Its modular, extensible architecture invites custom components and adapters, while the included example flowgraphs in the misc/ directory provide ready-to-run starting points. The project emphasizes testability, with comprehensive unit tests powered by pytest. Quickstart steps highlight Python >= 3.13, GNURadio (tested with GNURadio Companion v3.10.12.0), and UV-based virtual environments, including a sample client configuration to register the gr-mcp server for UV tooling. The project is in active development, with core functionality available and API/features continually evolving.