Technical Guide

How to use Feature Flag MCP server in Asp.Net Core Project

Name: FeatBit
Rating: 4.8 (1500 reviews)
Author: FeatBit

A comprehensive guide to implementing feature flags in ASP.NET Core using FeatBit SDK with MCP server integration

📅 Updated October 2025⏱️ 15 min read🎯 Intermediate

Introduction

Feature flags are a powerful technique that allows you to toggle features on and off without deploying new code. This guide will walk you through setting up feature flags in your .NET project using FeatBit SDK, integrated with MCP (Model Context Protocol) server for enhanced development experience.

Table of Contents

1.Configure MCP Server

2.Use VS Code to Initialize FeatBit SDK in ASP.NET Core

3.Create API to Implement Feature Flags

4.Testing Your Feature Flag API

1Configure MCP Server

What is MCP Server?

Model Context Protocol (MCP) server provides a standardized way for AI assistants to access external tools and data sources.

The MCP server acts as a bridge between your development environment and external services, enabling seamless integration with feature flag management systems like FeatBit.

1Find FeatBit .NET SDK MCP Server on Context7

Navigate to Context7 and locate the FeatBit Server-Side SDK for .NET documentation. Context7 provides access to comprehensive SDK documentation and implementation guides.

Context7 Dashboard with FeatBit SDK

Screenshot showing Context7 interface loaded with FeatBit Server-Side SDK for .NET documentation

2Configure VS Code mcp.json file, add Context7 as MCP Server Provider

Add Context7 as a MCP server provider in your VS Code configuration to enable seamless integration with FeatBit .NET SDK documentation and tooling.

// mcp.json configuration

{
  "servers": {
    "github-mcp": {
      "type": "http",
      "url": "https://api.githubcopilot.com/mcp"
    },
    "context7": {
      "type": "http",
      "url": "https://mcp.context7.com/mcp",
      "headers": {
        "CONTEXT7_API_KEY": "{{YOUR_API_KEY}}"
      }
    }
  }
}

✅ Once configured, Context7 will provide real-time access to FeatBit SDK documentation, code completion support, and implementation guidance directly in your VS Code environment.

2Use VS Code to Initialize FeatBit SDK in ASP.NET Core

Automated Setup with VS Code Agent

Use VS Code's AI agent with Context7 MCP server to automatically initialize FeatBit SDK in your ASP.NET Core project

1Chat with VS Code Agent

Start by opening VS Code chat and providing a prompt that mentions Context7 to integrate FeatBit dotnet SDK into your ASP.NET Core project.

VS Code Chat Interface

Screenshot showing how to interact with VS Code agent using Context7

💬 "I need you to integrate FeatBit dotnet SDK into this asp.net core project. Please use context7's featbit/featbit-dotnet-sdk for reference."

2Wait for Agent to Run Automatically

The VS Code agent will communicate with the MCP server and perform the following automated steps:

2.1

Initialize Code

The agent will analyze your project structure and initialize the necessary FeatBit SDK integration code in your Program.cs file.

2.2

Add Configurations

Configuration files (appsettings.json, appsettings.Development.json) will be updated with FeatBit settings including EnvSecret, StreamingUri, and EventUrl.

2.3

Install Missing Packages

The agent will automatically run dotnet restore to install the FeatBit.ServerSdk package and any dependencies.

2.4

Build and Debug

Finally, the agent will run dotnet build to ensure there are no compilation errors and verify the integration is complete.

✅Integration Complete

Once the agent finishes, your ASP.NET Core project will be fully configured with FeatBit SDK and ready to use feature flags.

3Create API to Implement Feature Flags

Building Feature Flag API Endpoints

Create a new API that allows external services to retrieve feature flag values by providing user information

We'll create a new API to let external services retrieve a single feature flag value by providing user information (key, name, and custom properties). This API will expose different feature flag type endpoints such as boolean, string, number, and JSON string.

1Define the Prompt for VS Code Agent

The prompt is very simple. We ask the VS Code agent to help us create the feature flag API:

# Prompt for VS Code Agent

I need you to remove WeatherForecast api,

and create a new api, the main objective is to receive user key, name and customized properties, then call featbit sdk to get the evaluated feature flag value for the given user information.

i need you expose different feature flag type apis, such as boolean, string, number, json string.

note:
- use featbit feature flag
- use context7 as mcp server

2AI Learning from Context7 MCP Server

The VS Code agent learns from Context7 MCP server to implement the correct feature flag code and construct the API. Context7 provides the necessary documentation and examples for FeatBit .NET SDK, enabling the AI to generate accurate implementation.

💡 How it works: The AI agent uses the Context7 MCP server to access FeatBit SDK documentation, understanding the proper usage patterns and generating appropriate API code based on the requirements.

3Generated API Implementation Example

As a real code example, the AI helps us create an API "/api/featureflag/boolean" with the `EvaluateBooleanFlag` method. This method takes user information in the request body, then calls the `BoolVariation` function provided by the FeatBit .NET server SDK, and returns the feature flag evaluation details for the given user.

AI-Generated Feature Flag API Implementation

Screenshot showing the AI agent implementing feature flag API methods using FeatBit SDK

💻Complete Implementation Code

For the complete FeatureFlagController.cs implementation and all related code examples, visit our comprehensive GitHub repository. All code in this repository has been generated by VS Code Agent to ensure best practices and optimal implementation.

View Complete Code Repository

⚡ Generated by VS Code Agent | 🔧 Production Ready | 📚 Comprehensive Documentation

4Testing Your Feature Flag API

Testing Your Feature Flag API

Test the different feature flag endpoints to verify functionality

Test Boolean Flag Endpoint

# Test boolean feature flag
curl --location 'https://featgen-customer-ff-api-ecbdbgh9fzazaeep.westus-01.azurewebsites.net/api/FeatureFlag/boolean' \
--header 'Content-Type: application/json' \
--header 'Cookie: ARRAffinity=d242e3a14517086d5f3ad5ccb7ecac798999635e8e3f838b583f16ee6eb2d72b; ARRAffinitySameSite=d242e3a14517086d5f3ad5ccb7ecac798999635e8e3f838b583f16ee6eb2d72b' \
--data '{
    "UserKey": "project_1164",
    "Name": "project_1164",
    "FlagKey": "enable-agent-v2"
}'

Example Response

{
    "flagKey": "enable-agent-v2",
    "value": true,
    "userId": "project_1164",
    "evaluatedAt": "2025-10-14T07:55:19.0427215Z"
}

✅ Success Indicators

API returns feature flag values based on user context
Different flag types (boolean, string, number, JSON) work correctly
Custom properties are properly passed to FeatBit SDK
Evaluation reasons are returned for debugging
No errors in application logs

Conclusion

You've successfully implemented feature flags in your .NET project using FeatBit SDK with MCP server integration. This setup provides you with powerful capabilities to control feature rollouts, conduct A/B tests, and manage application behavior without deploying new code.