Arithmetic + Logic MCP Implementation

[Alexandre-Roussel48]

This pull request introduces the implementation of an Arithmetic + Logic MCP (Model Context Protocol) server in Scala 3 using ZIO and Circe. It establishes a modular, layered architecture for a JSON-RPC server over STDIO, providing arithmetic and logic tools for editor integrations such as VS Code with Copilot Agent Mode. The changes include project setup, a comprehensive README, the main application entrypoint, configuration and data models for the MCP protocol, error handling, and the initial routing and handler layers.

The most important changes are:

Project Setup & Documentation

• Added a detailed README.md describing the server's purpose, architecture, usage with Docker and VS Code, Copilot Agent Mode requirements, and testing approach.
• Added project build files: build.properties specifying sbt version and plugins.sbt adding the assembly plugin for packaging. [1] [2]

Core Application & Architecture

• Introduced the main application entrypoint in Main.scala, composing ZIO layers for configuration, session, tool registry, routing, and STDIO transport, and implementing the main loop for handling JSON-RPC messages.
• Defined the configuration layer in ServerConfig.scala, including server metadata and capabilities, exposed as a ZIO layer.

Protocol & Data Models

• Implemented JSON-RPC protocol data models: message envelopes (JsonRpcMessage.scala), error codes (JsonRpcError.scala), and request IDs (JsonRpcId.scala). [1] [2] [3]
• Added MCP protocol data models for initialization, capabilities, and tool invocation, including codecs for Circe serialization. [1] [2] [3]

Routing & Error Handling

• Added the initial routing and handler layers, including InitializeHandler.scala for handling initialization requests, and ErrorMapping.scala for mapping internal errors to JSON-RPC error responses. [1] [2]

These changes lay the foundation for a robust, testable MCP server providing arithmetic and logic tools over a standard protocol for editor integrations.

• Project Setup & Documentation:

  • Added detailed README.md and project build files (build.properties, plugins.sbt). [1] [2] [3]

• Core Application & Architecture:

  • Implemented Main.scala with ZIO layer composition and main server loop.
  • Provided configuration via ServerConfig.scala as a ZIO layer.

• Protocol & Data Models:

  • Defined JSON-RPC message, error, and ID models with Circe codecs. [1] [2] [3]
  • Added MCP protocol models for initialization, capabilities, and tools. [1] [2] [3]

• Routing & Error Handling:

  • Implemented InitializeHandler for initialization requests and ErrorMapping for error translation. [1] [2]