CSharpMCP Server

Overview

The CSharpMCP server is a specialized Model Context Protocol (MCP) endpoint that enables AI assistants to execute C# code snippets directly on the host machine using Roslyn, Microsoft’s .NET compiler platform. By exposing a set of lightweight tools—, , and —the server provides a safe, stateful environment for rapid prototyping, debugging, and data manipulation within an AI-driven workflow. Developers can seamlessly embed C# logic into conversational agents, allowing the assistant to perform complex calculations, transform data structures, or interact with .NET libraries without leaving the chat interface.

Problem Solved

Many AI assistants are limited to text-based responses or rely on external APIs for computation. When a developer needs to run native C# code, they typically have to switch contexts, invoke a separate compiler or REPL, and then feed results back into the assistant. CSharpMCP eliminates this friction by turning code execution into a first‑class MCP tool. It removes the need for manual compilation steps, handles state persistence across interactions, and integrates directly into the assistant’s prompt loop.

Core Capabilities

• RunAsync: Accepts a block of C# code and executes it asynchronously. The execution context is preserved, so variables declared in one turn are available in subsequent turns, mirroring a persistent REPL session. This is ideal for iterative development or exploratory data analysis.
• CleanExecuteContext: Resets the execution environment, clearing all stored variables and state. This tool is useful when starting a new task or isolating experiments to avoid cross‑talk between sessions.
• GetHistoryCode: Retrieves the accumulated code history, allowing the assistant or developer to review past executions, debug issues, or audit changes over time.

Real‑World Use Cases

• Rapid prototyping: Developers can draft algorithms or utility functions within a chat, test them instantly, and refine the logic on the fly.
• Educational tools: Instructors can demonstrate C# concepts interactively, letting students write and run code snippets directly in the conversation.
• Data transformation: AI assistants can pull data from a database, transform it with C# LINQ queries, and return results—all within the same dialogue.
• Automation scripts: Complex build or deployment scripts can be assembled and executed dynamically, reducing manual copy‑paste steps.

Integration with AI Workflows

Because CSharpMCP adheres to the MCP specification, any Claude or other MCP‑compatible assistant can invoke its tools without custom adapters. The server’s stateful nature aligns with the conversational context model, ensuring that variables and objects persist across turns. Developers can embed tool calls directly into prompts or let the assistant decide when to execute code, creating a fluid loop between natural language instructions and executable logic.

Unique Advantages

• Native Roslyn integration: Leveraging the full power of .NET’s compiler services means features like syntax highlighting, IntelliSense, and compile‑time diagnostics are available without extra libraries.
• Security awareness: The README explicitly warns that code runs locally, encouraging cautious use and highlighting the need for sandboxing or permission controls—an important consideration when exposing execution to untrusted input.
• Project reference support: By passing a compiled DLL as a startup parameter, the server automatically adds references to existing projects. This allows developers to tap into their own libraries and assemblies, extending the assistant’s capabilities beyond standard .NET packages.

In summary, CSharpMCP turns a local machine into an interactive, stateful C# execution engine that plugs cleanly into AI assistants. It bridges the gap between conversational AI and native code execution, empowering developers to build richer, more dynamic applications without leaving the chat environment.