Connecting Claude and Other LLMs to a Custom .NET MCP Server – A Production‑Ready Guide

Quick Answer connecting Claude and other LLMs to a custom .NET MCP server: Learn how to architect, secure, and optimize a custom .NET MCP server for Claude, Azure OpenAI, and other LLMs. Real‑world code, performance tricks, and production pitfalls included. Black-Box LLM Pitfalls When you bolt Claude, GPT‑4 or any other LLM straight into a .NET endpoint, the first 200 requests look great. But as soon as you hit a few hundred concurrent users, you start seeing a cascade of symptoms: 200‑plus millisecond latency, sporadic 429s, cache pollution, and a brittle tool‑calling pipeline that breaks on the slightest provider change. The root cause is that most quick‑starts treat the LLM as a black‑box HTTP call and ignore the Model Context Protocol (MCP), the contract that lets you swap providers, reuse KV caches, and enforce tenant isolation without touching business logic. Real‑World Example Consider a SaaS company that offers a knowledge‑base