Adding an article and an agent skill, to add Entra ID to an aspire app

.github/skills/README.md

@@ -0,0 +1,121 @@
+# AI Coding Assistant Skills for Microsoft.Identity.Web
+
+This folder contains **Skills** - specialized knowledge modules that help AI coding assistants provide better assistance for specific scenarios.
+
+## What Are Skills?
+
+Skills are an **open standard** for sharing domain-specific knowledge with AI coding assistants. They are markdown files with structured guidance that AI assistants use when helping with specific tasks. Unlike general instructions, skills are **scenario-specific** and activated when the assistant detects relevant context (keywords, file patterns, or explicit requests).
+
+### Supported AI Assistants
+
+Skills work with multiple AI coding assistants that support the open skills format:
+
+- **GitHub Copilot** - Native support in VS Code, Visual Studio, GitHub Copilot CLI,  and other IDEs
+- **Claude** (Anthropic) - Via Claude for VS Code extension and Claude Code
+- **Other assistants** - Any AI tool that follows the skills convention
+
+## Available Skills
+
+| Skill | Description | Full Guide |
+|-------|-------------|------------|
+| [entra-id-aspire-authentication](./entra-id-aspire-authentication/SKILL.md) | Adding Microsoft Entra ID authentication to .NET Aspire applications | [Aspire Integration Guide](../../docs/frameworks/aspire.md) |
+
+> **💡 Tip:** Skills are condensed versions optimized for AI assistants. For comprehensive documentation with detailed explanations, diagrams, and troubleshooting, see the linked full guides.
+
+## How to Use Skills
+
+### Option 1: Repository-Level (Recommended for Teams)
+
+Copy the skill folder to your project's `.github/skills/` directory:
+
+```
+your-repo/
+├── .github/
+│   └── skills/
+│       └── entra-id-aspire-authentication/
+│           └── SKILL.md
+```
+
+Copilot will automatically use this skill when working in your repository.
+
+### Option 2: User-Level (Personal Setup)
+
+Install skills globally so they're available across all your projects:
+
+**Windows:**
+```powershell
+# Create the skills directory
+mkdir "$env:USERPROFILE\.github\skills\entra-id-aspire-authentication" -Force
+
+# Copy the skill (or download from this repo)
+Copy-Item "SKILL.md" "$env:USERPROFILE\.github\skills\entra-id-aspire-authentication\"
+```
+
+Location: `%USERPROFILE%\.github\skills\`
+
+**Linux / macOS:**
+```bash
+# Create the skills directory
+mkdir -p ~/.github/skills/entra-id-aspire-authentication
+
+# Copy the skill (or download from this repo)
+cp SKILL.md ~/.github/skills/entra-id-aspire-authentication/
+```
+
+Location: `~/.github/skills/`
+
+### Option 3: Reference in Chat
+
+You can also explicitly tell Copilot to use a skill:
+
+> "Using the entra-id-aspire-authentication skill, add authentication to my Aspire app"
+
+## Skill File Structure
+
+Each skill follows this structure:
+
+```markdown
+---
+name: skill-name
+description: When Copilot should use this skill
+license: MIT
+---
+
+# Skill Title
+
+## When to Use This Skill
+- Trigger condition 1
+- Trigger condition 2
+
+## Implementation Guide
+...
+```
+
+The YAML frontmatter helps AI assistants understand when to apply the skill.
+
+## Creating New Skills
+
+1. Create a folder under `.github/skills/` with your skill name
+2. Add a `SKILL.md` file with:
+   - YAML frontmatter (`name`, `description`, `license`)
+   - Clear "When to Use" section
+   - Step-by-step implementation guidance
+   - Code examples and configuration snippets
+   - Troubleshooting tips
+
+## Skills vs. Instructions
+
+| Aspect | Instructions file | Skills |
+|--------|-------------------|--------|
+| Scope | Always active for the repo | Activated by context/keywords |
+| Purpose | General coding standards | Specific implementation scenarios |
+| Location | `.github/copilot-instructions.md` | `.github/skills/<name>/SKILL.md` |
+| Content | Style guides, conventions | Step-by-step tutorials, patterns |
+| Standard | Varies by AI assistant | Open standard across assistants |
+
+## Resources
+
+- [Microsoft.Identity.Web Documentation](../../docs/README.md)
+- [Aspire Integration Guide](../../docs/frameworks/aspire.md)
+- [GitHub copilot skills](https://docs.github.com/en/copilot/concepts/agents/about-agent-skills)
+- [GitHub Copilot Documentation](https://docs.github.com/copilot)