Open Source C# Model Context Protocol (MCP) Servers

ModelContextProtocol.NET is a C# SDK that implements the Model Context Protocol (MCP), allowing developers to build MCP servers on the .NET platform. It supports standard input/output communication and provides a framework for tool integration. The SDK is compatible with Native AOT, enhancing performance and deployment flexibility. A calculator demo implementation is included to demonstrate its capabilities. Features under development include WebSocket support, resource management, and a prompt system. ​

Microsoft’s MCP Gateway is a reverse proxy and management layer for MCP servers that adds session-aware routing, lifecycle management, and scalable orchestration. It centralizes how clients connect to many MCP services, enabling multi-tenant isolation and consistent policies while keeping each service independently deployable. The architecture targets Kubernetes, with manifests and guidance for cluster-native scaling, health probes, and rollout strategies. It also includes local and Azure deployment recipes, making it straightforward to try on a laptop and then promote to cloud infrastructure. Core concepts—like session routing, server pools, and pluggable policies—are documented to help teams reason about stateful agent sessions at scale. By standardizing discovery and control, it reduces operational toil and improves reliability for agent platforms built on MCP.