FoundationModels MCP Server

Overview

The FoundationModels MCP server bridges Apple’s on‑device language models with AI assistants that speak the Model Context Protocol. By exposing these models as an MCP endpoint, developers can embed secure, private text generation directly into their assistant workflows without relying on external cloud services. This solves the common problem of latency, privacy concerns, and data‑exposure risks that arise when sending user prompts to remote APIs.

At its core, the server wraps Apple’s Foundation Models framework in a lightweight command‑line executable. When an MCP client sends a generation request, the server forwards the prompt to the on‑device model and streams back the generated text. Because all computation happens locally, response times are typically sub‑second on Apple Silicon Macs, and no user data leaves the device. For developers building chatbots, creative writing tools, or internal knowledge bases, this guarantees compliance with strict data‑handling policies while still delivering high‑quality language generation.

Key capabilities include:

• On‑device inference: Utilizes the latest Apple Silicon neural engine for fast, low‑power generation.
• System instruction support: The environment variable allows the server to prepend a default context to every request, enabling consistent behavior across sessions.
• Debug logging: A simple flag () turns on verbose output, useful during development and troubleshooting.
• Graceful lifecycle management: Built with , the server can be started and stopped cleanly, making it suitable for long‑running assistant processes.

Typical use cases involve integrating the server into desktop AI assistants such as Claude Desktop, or any MCP‑compatible client. For instance, a developer can add the server to the assistant’s configuration file and then invoke it as an “internal” tool that never touches the network. This is ideal for enterprise environments, offline creative workstations, or privacy‑first applications where user text must never leave the local machine.

By offering a straightforward, standards‑based interface to Apple’s powerful language models, FoundationModels gives developers a reliable, low‑overhead option for secure text generation. Its tight coupling with macOS and Swift ecosystems also means minimal friction when adding or updating the server, making it a compelling choice for anyone looking to keep AI workflows entirely within their own infrastructure.