configuration

Q: How do I install configuration?

Run npx skills add https://github.com/codewithmukesh/dotnet-claude-kit --skill configuration in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/configuration/ (personal) or .claude/skills/configuration/ (project).

by codewithmukeshSecurity

Configuration patterns for .NET 10 applications. Covers the Options pattern, IOptionsSnapshot vs IOptions, secrets management, and environment-based configuration. Load this skill when setting up application configuration, managing secrets, binding configuration sections, or when the user mentions "configuration", "appsettings", "Options pattern", "IOptions", "IOptionsSnapshot", "secrets", "user secrets", "environment variables", "connection string", or "config binding".

Installs: 2.9K
Last 24h: +55
Trending rank: #3130
Security: Not audited

Install

Works with every agent the skills CLI supports.

npx skills add https://github.com/codewithmukesh/dotnet-claude-kit --skill configuration

01
Install
Run the command in your project. The CLI asks which agents to install for.
02
Describe the task
Ask your agent for something this skill covers. It loads configuration automatically when relevant.
03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.

SKILL.md

The instructions your agent reads when the skill is triggered.

Configuration

Core Principles

Options pattern always — Never read IConfiguration directly in services. Bind configuration sections to strongly-typed classes with validation.
Validate on startup — Use ValidateDataAnnotations() and ValidateOnStart() to catch misconfiguration before the first request.
Secrets never in source — Use user secrets in development, Azure Key Vault or environment variables in production. Never commit secrets to git.
Configuration layering — appsettings.json → appsettings.{Environment}.json → environment variables → user secrets. Later sources override earlier ones.

Patterns

Options Pattern

// Options class with validation attributes
public class DatabaseOptions
{
    public const string SectionName = "Database";

    [Required]
    public required string ConnectionString { get; init; }

    [Range(1, 100)]
    public int MaxRetryCount { get; init; } = 3;

    [Range(1, 60)]
    public int CommandTimeoutSeconds { get; init; } = 30;
}

// Registration with validation
builder.Services.AddOptions<DatabaseOptions>()
    .BindConfiguration(DatabaseOptions.SectionName)
    .ValidateDataAnnotations()
    .ValidateOnStart(); // Fails at startup if configuration is invalid

// appsettings.json
{
  "Database": {
    "ConnectionString": "",
    "MaxRetryCount": 3,
    "CommandTimeoutSeconds": 30
  }
}

Injecting Options

// IOptions<T> — singleton, read once at startup, doesn't change
public class OrderService(IOptions<DatabaseOptions> options)
{
    private readonly DatabaseOptions _db = options.Value;
}

// IOptionsSnapshot<T> — scoped, re-reads per request (for reloadable config)
public class OrderService(IOptionsSnapshot<DatabaseOptions> options)
{
    private readonly DatabaseOptions _db = options.Value;
}

// IOptionsMonitor<T> — singleton, actively watches for changes
public class BackgroundWorker(IOptionsMonitor<WorkerOptions> options)
{
    public void DoWork()
    {
        var current = options.CurrentValue; // Always latest
    }
}

Custom Validation (Complex Rules)

builder.Services.AddOptions<JwtOptions>()
    .BindConfiguration("Jwt")
    .Validate(options =>
    {
        if (string.IsNullOrEmpty(options.Key) || options.Key.Length < 32)
            return false;
        if (options.ExpirationMinutes <= 0)
            return false;
        return true;
    }, "JWT key must be at least 32 characters and expiration must be positive")
    .ValidateOnStart();

Azure Key Vault (Production)

// Program.cs — add Key Vault as a configuration source
if (builder.Environment.IsProduction())
{
    var keyVaultUri = new Uri(builder.Configuration["KeyVault:Uri"]!);
    builder.Configuration.AddAzureKeyVault(keyVaultUri, new DefaultAzureCredential());
}

Configuration for Multiple Environments

// Named options — different config per named instance
builder.Services.AddOptions<SmtpOptions>("internal")
    .BindConfiguration("Smtp:Internal");
builder.Services.AddOptions<SmtpOptions>("customer")
    .BindConfiguration("Smtp:Customer");

// Usage
public class EmailService(IOptionsSnapshot<SmtpOptions> options)
{
    public async Task SendInternalEmail(string to, string body)
    {
        var smtp = options.Get("internal");
        // ...
    }
}

Anti-patterns

Don't Read IConfiguration Directly

// BAD — stringly-typed, no validation, hard to test
public class OrderService(IConfiguration config)
{
    public void Process()
    {
        var timeout = int.Parse(config["Database:CommandTimeout"]!);
    }
}

// GOOD — strongly-typed options
public class OrderService(IOptions<DatabaseOptions> options)
{
    public void Process()
    {
        var timeout = options.Value.CommandTimeoutSeconds;
    }
}

Don't Put Secrets in appsettings.json

// BAD — committed to source control
{
  "Jwt": { "Key": "super-secret-key" },
  "Database": { "ConnectionString": "Server=prod;Password=secret" }
}

// GOOD — appsettings.json has defaults/structure only
{
  "Jwt": { "Key": "", "Issuer": "myapp", "Audience": "myapp" },
  "Database": { "ConnectionString": "" }
}
// Secrets provided via user-secrets (dev) or env vars / Key Vault (prod)

Don't Skip Startup Validation

// BAD — misconfiguration discovered at runtime
builder.Services.Configure<JwtOptions>(builder.Configuration.GetSection("Jwt"));

// GOOD — fail fast at startup
builder.Services.AddOptions<JwtOptions>()
    .BindConfiguration("Jwt")
    .ValidateDataAnnotations()
    .ValidateOnStart();

Decision Guide

Scenario	Recommendation
Binding config to class	Options pattern with `BindConfiguration`
Simple, immutable config	`IOptions<T>`
Config that changes per request	`IOptionsSnapshot<T>`
Background service watching config	`IOptionsMonitor<T>`
Development secrets	`dotnet user-secrets`
Production secrets	Azure Key Vault or environment variables
Validating config	`ValidateDataAnnotations()` + `ValidateOnStart()`
Multiple configs of same type	Named options with `IOptionsSnapshot<T>.Get(name)`

FAQ

What does the configuration skill do?

How do I install configuration?

Run npx skills add https://github.com/codewithmukesh/dotnet-claude-kit --skill configuration in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/configuration/ (personal) or .claude/skills/configuration/ (project).

Which AI agents can use configuration?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Is configuration safe to install?

No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.

Who maintains configuration?

It is published by codewithmukesh in codewithmukesh/dotnet-claude-kit. It has 2,868 recorded installs.