Simple Dart MCP Server

Overview

The Simple Dart MCP Server is a lightweight implementation of the Model Context Protocol written in Dart. It bridges AI assistants such as Claude with external services by exposing a set of resources, tools, prompts, and sampling endpoints over both standard input/output (stdio) and WebSocket transports. This dual‑transport design allows the server to be embedded in command‑line workflows or deployed as a network service, giving developers flexibility in how they integrate AI capabilities into their pipelines.

At its core, the server addresses the need for a minimal yet functional MCP host that can be quickly spun up without extensive configuration. By leveraging Dart’s async I/O and strong type system, the implementation keeps boilerplate to a minimum while still supporting the full MCP message schema. Developers can thus focus on defining domain‑specific tools or resources—such as database queries, file system operations, or external API calls—without wrestling with protocol details. The server’s design encourages reuse; the same codebase can serve as a local test harness or be exposed to remote clients over WebSocket for production use.

Key features include:

• Transport flexibility: Supports both stdio (ideal for local testing or CI environments) and WebSocket (for networked deployments), allowing the same binary to be used in diverse contexts.
• Protocol compliance: Implements the MCP message types and lifecycle events required by AI assistants, ensuring seamless communication without custom adapters.
• Extensibility hooks: Exposes a simple API for registering new tools or resources, enabling developers to add bespoke functionality (e.g., invoking a REST API, running shell commands) with minimal code.
• Community‑driven foundation: Builds upon the Dart MCP classes from an open‑source project, inheriting proven parsing and serialization logic while keeping the implementation lightweight.

Typical use cases include:

• Rapid prototyping: Quickly expose a local script or command as an MCP tool so that an AI assistant can invoke it during conversation.
• Continuous integration: Run the server in a CI pipeline via stdio to validate tool interactions before deploying to production.
• Edge deployment: Deploy the WebSocket variant on a local network device, allowing nearby AI assistants to access domain‑specific data or services without internet exposure.
• Educational demonstrations: Showcase how MCP works by integrating the server into teaching materials or workshops.

Because it is written in Dart, the Simple MCP Server can be compiled to native binaries for multiple platforms (Linux, macOS, Windows) or run on the JVM via Dart2JavaScript. This cross‑platform support gives teams that already use Dart for other services a familiar ecosystem, reducing onboarding friction. The server’s minimal footprint and clear API make it an ideal starting point for developers who need a dependable MCP host without the overhead of larger frameworks.