Add DSC MCP server concept doc

docs/concepts/dsc-mcp-server.md

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+---
+description: >-
+  DSC includes a Model Context Protocol (MCP) server that enables AI agents and tools to
+  interact with DSC resources and functions through a standardized interface. This integration
+  enhances the authoring experience in supported editors like VS Code.
+ms.date: 09/26/2025
+title: Using DSC with Model Context Protocol (MCP) Server
+---
+
+# Using DSC with Model Context Protocol (MCP) Server
+
+Microsoft's Desired State Configuration (DSC) platform includes a built-in Model Context Protocol
+(MCP) server that enables AI agents and development tools to interact with DSC resources and
+configurations through a standardized interface. This integration provides intelligent assistance  
+for discovering, invoking, and understanding DSC resources and functions on your system.
+
+The DSC MCP server exposes DSC's core functionality to AI agents, enabling them to help you
+discover resources, understand their schemas, and work with DSC functions in an intelligent way.
+This enhances the overall authoring experience by providing contextual information about your
+local DSC environment directly to AI-powered tools.
+
+> [!IMPORTANT]
+> The DSC MCP server is focused on discovery and information retrieval. It does not
+> directly perform any configuration changes or resource modifications unless requested to do so.
+> The information it provides to AI agents can be used to generate configurations and commands
+> that, when executed, will impact your system. Always review and validate any generated
+> content before execution.
+
+## What is Model Context Protocol (MCP)?
+
+Model Context Protocol (MCP) is an open standard that enables AI agents to securely connect to
+external data sources and tools. To learn more about MCP and how it works with AI agents, see
+[Use MCP servers in VS Code][00].
+
+## How AI agents use DSC MCP tools
+
+The DSC MCP server enables AI agents to intelligently assist you by understanding what's
+available in your local DSC environment. Here's how agents use these capabilities to help
+fulfill your requests:
+
+### Discovering available resources
+
+When you ask an agent to help with system configuration tasks, the agent can discover what DSC
+resources are available on your machine. For example:
+
+- **You ask**: "How can I manage Windows registry settings?"
+- **Agent discovers**: The `Microsoft.Windows/Registry` resource is available
+- **Agent provides**: Specific guidance on using that resource for your registry management
+  needs
+
+This discovery helps agents provide accurate, system-specific recommendations rather than
+generic advice.
+
+### Understanding resource capabilities
+
+When you need to configure something specific, agents can examine the exact properties and
+capabilities of relevant resources. For instance:
+
+- **You ask**: "I need to install packages on my Linux system using apt"  
+- **Agent examines**: The `Microsoft.Linux.Apt/Package` resource schema
+- **Agent provides**: The exact property names and valid values needed for your package
+  installation configuration
+
+This ensures the guidance you receive matches what's actually available on your system.
+
+### Working with DSC functions
+
+When you're building configuration expressions, agents can discover what functions are available
+to help solve your specific needs:
+
+- **You ask**: "How do I combine multiple arrays in a DSC configuration?"
+- **Agent discovers**: Functions like `union()`, `intersection()`, and `concat()` are available
+- **Agent provides**: Examples using the appropriate function for your use case
+
+This helps agents suggest the most suitable approach using your available DSC capabilities.
+
+> [!NOTE]
+> Additional MCP tools will become available in future releases to expand the capabilities
+> of the DSC MCP server integration. For the latest updates and feature announcements,
+> visit the [official DSC repository][01] on GitHub.
+
+## How DSC MCP integrates with VS Code
+
+The following diagram illustrates how the DSC MCP server integrates with VS Code and AI agents:
+
+```mermaid
+graph TD
+    A[VS Code] -->|Copilot Chat| B[AI Agent]
+    B -->|MCP Protocol| C[DSC MCP Server]
+    C -->|dsc commands| D[DSC CLI]
+    D -->|Discovery| E[Local DSC Resources]
+    D -->|Schema| F[Resource Manifests]
+    D -->|Functions| G[DSC Function Registry]
+
+    B -->|Enhanced assistance| H[Configuration Document]
+    B -->|Resource suggestions| I[IntelliSense]
+    B -->|Schema validation| J[Error messages]
+
+    style C fill:#e1f5fe
+    style D fill:#f3e5f5
+    style A fill:#e8f5e8
+```
+
+The integration works as follows:
+
+1. **VS Code Copilot** communicates with AI agents that can access MCP servers
+2. **AI agents** use the MCP protocol to query the DSC MCP server for information
+3. **DSC MCP server** processes requests and calls the appropriate DSC CLI commands
+4. **DSC CLI** performs resource discovery, schema retrieval, and function enumeration
+5. **Results** flow back through the chain to provide enhanced authoring assistance
+
+## Prerequisites
+
+Before using the DSC MCP server integration, ensure you have:
+
+- DSC v3.2.0-preview.5 or later installed on your system
+- VS Code v1.104 or above with [GitHub Copilot extension][02] enabled
+- Access to [Copilot in VS Code][03]
+
+## Setting up DSC MCP Server
+
+### Method 1: Using mcp.json configuration file
+
+The recommended way to configure the DSC MCP server is through an `mcp.json` configuration file.
+Create or update your MCP configuration file with the following content in the `.vscode` folder:
+
+```json
+{
+  "servers": {
+    "dsc-mcp": {
+      "type": "stdio",
+      "command": "dsc",
+      "args": [
+        "mcp"
+      ]
+    }
+  },
+  "inputs": []
+}
+```
+
+This configuration tells MCP clients to:
+
+- Run the `dsc mcp` command to start the DSC MCP server.
+- Use standard I/O communication between the client and server.
+- Register the server with the identifier `dsc-mcp`.
+
+For detailed information about MCP configuration and setup in VS Code, refer to the
+[official MCP documentation][04].
+
+### Method 2: Manual command-line setup
+
+You can also start the DSC MCP server manually for testing or development purposes:
+
+```powershell
+dsc mcp
+```
+
+This command starts the DSC MCP server and waits for MCP protocol messages on standard input.
+The server will continue running until terminated or the input stream is closed.
+
+:::image type="complex" source="media/dsc-mcp-server/dsc-mcp-startup.png" alt-text="Screenshot showing DSC MCP server startup in terminal":::
+   This screenshot shows the DSC MCP server starting up in a PowerShell terminal window. The command `dsc mcp` has been executed and the server is running, waiting for MCP protocol messages on standard input.
+:::image-end:::
+
+## Using DSC MCP tools in VS Code
+
+### Step 1: Open Copilot Chat in Agent Mode
+
+1. Open the GitHub Copilot extension window in VS Code
+2. Select "Agent Mode" to enable MCP tool integration
+
+:::image type="complex" source="media/dsc-mcp-server/agent-mode-selection.png" alt-text="Screenshot showing Agent Mode selection in VS Code":::
+   This screenshot shows the GitHub Copilot extension window in VS Code with Agent Mode being selected to enable MCP tool integration.
+:::image-end:::
+
+### Step 2: Access DSC MCP tools
+
+1. Click on the tool icon in the GitHub Copilot chat window.
+2. Search for "MCP Server: dsc-mcp" in the available tools list.
+3. Verify that the DSC MCP server tools are available and loaded.
+
+:::image type="complex" source="media/dsc-mcp-server/dsc-mcp-tools-selection.png" alt-text="Screenshot showing DSC MCP tools selection interface":::
+   This screenshot shows the GitHub Copilot chat window with the tools list displayed, highlighting the DSC MCP server tools that are available for selection.
+:::image-end:::
+
+### Step 3: Start using DSC MCP integration
+
+Begin asking questions or requesting assistance with DSC-related tasks. The AI agent will
+automatically use the DSC MCP tools when appropriate to provide accurate, context-aware help.
+
+Example prompts that work well with DSC MCP integration:
+
+- "What DSC resources are available on this machine?"
+- "Show me the schema for the Microsoft.Windows/Registry resource"
+- "List all available DSC functions I can use in expressions"
+
+:::image type="complex" source="media/dsc-mcp-server/dsc-mcp-usage-example.png" alt-text="Screenshot showing DSC MCP usage example in VS Code":::
+   This screenshot demonstrates the DSC MCP integration in action, showing how AI agents use the MCP tools to provide contextual assistance with DSC-related tasks in VS Code.
+:::image-end:::
+
+## Troubleshooting
+
+### Connection issues
+
+If you encounter connection issues between VS Code and the DSC MCP server:
+
+1. Verify your `mcp.json` configuration file syntax
+2. Check that the `dsc` command is available in your system PATH
+3. Review VS Code's output panel for detailed error messages
+4. Try restarting the MCP integration in VS Code
+
+### Limited or no response from AI Agent
+
+If the AI agent doesn't seem to be using DSC MCP tools:
+
+- Use specific prompts that clearly indicate you want DSC-related information
+- Try phrases like "List DSC resources" or "Show me DSC functions"
+- Verify that Agent Mode is enabled in Copilot Chat
+- Check if the DSC MCP tools are visible in the tools list
+
+## Limitations
+
+> [!IMPORTANT]
+> It is your responsibility to review all configuration documents and commands generated with
+> AI assistance. **Always validate configurations in a test environment before applying them
+> to production systems.**
+
+Current limitations of the DSC MCP server integration include:
+
+- **Local machine scope**: Information is limited to resources and functions available on the
+  local machine where the server runs
+- **Agent behavior**: There is no guarantee that AI agents will use DSC MCP tools for any
+  particular query, though specific prompting can help guide tool usage
+
+## See also
+
+- [DSC Configuration document schema reference][05]
+- [DSC resource manifest schema reference][06]
+- [Use MCP servers in VS Code][00]
+- [Model Context Protocol documentation][07]
+- [Enhanced authoring with schemas][08]
+- [Improving output accessibility][09]
+
+<!-- Link reference definitions -->
+[00]: https://code.visualstudio.com/docs/copilot/chat/mcp-servers
+[01]: https://github.com/PowerShell/DSC
+[02]: https://marketplace.visualstudio.com/items?itemName=GitHub.copilot
+[03]: https://code.visualstudio.com/docs/copilot/overview
+[04]: https://code.visualstudio.com/docs/copilot/customization/mcp-servers
+[05]: ../reference/schemas/config/document.md
+[06]: ../reference/schemas/resource/manifest/root.md
+[07]: https://modelcontextprotocol.io/docs
+[08]: enhanced-authoring.md
+[09]: output-accessibility.md