VS Code Copilot Configuration¶

This guide explains how to configure VS Code with GitHub Copilot to use the RIDDL MCP Server for AI-assisted domain modeling.

Prerequisites¶

Visual Studio Code installed
GitHub Copilot extension installed and activated
GitHub Copilot Chat extension (for MCP support)
API key for the RIDDL MCP Server (contact support@ossuminc.com)

Configuration¶

VS Code Copilot uses the settings.json file for MCP server configuration.

Opening Settings¶

Open VS Code
Press Cmd+, (Mac) or Ctrl+, (Windows/Linux)
Click the Open Settings (JSON) icon in the top right
Or open directly: Cmd+Shift+P > "Preferences: Open User Settings (JSON)"

Adding the RIDDL MCP Server¶

Add the MCP server configuration to your settings.json:

{
  "github.copilot.chat.mcpServers": {
    "riddl": {
      "url": "https://mcp.ossuminc.com/mcp/v1",
      "headers": {
        "X-API-KEY": "your-api-key"
      }
    }
  }
}

Server Coming Soon

The hosted MCP server at mcp.ossuminc.com will be available in early 2026. For now, use a local server for development. Replace your-api-key with your actual API key.

Workspace-Level Configuration¶

For project-specific configuration, create or edit .vscode/settings.json in your workspace:

{
  "github.copilot.chat.mcpServers": {
    "riddl": {
      "url": "https://mcp.ossuminc.com/mcp/v1",
      "headers": {
        "X-API-KEY": "your-api-key"
      }
    }
  }
}

Using a Local Server¶

For development with a locally running server:

{
  "github.copilot.chat.mcpServers": {
    "riddl": {
      "url": "http://localhost:8080/mcp/v1",
      "headers": {
        "X-API-KEY": "your-local-api-key"
      }
    }
  }
}

Verify Connection¶

Open Copilot Chat (Cmd+Shift+I or Ctrl+Shift+I)
Ask: "Can you validate this RIDDL code?"
Paste some RIDDL code
Copilot should use the RIDDL validation tool

Using with RIDDL Files¶

Combined with RIDDL Extension¶

For the best experience, install both:

GitHub Copilot - AI assistance with MCP tools
RIDDL Language Support - Syntax highlighting and local validation

This gives you:

Real-time syntax highlighting
Local validation as you type
AI-powered assistance via Copilot Chat

Inline Assistance¶

While editing a .riddl file, use Copilot Chat:

"Add a command handler to this entity for updating the address"

Copilot can:

Understand the context of your current file
Use RIDDL MCP tools to validate suggestions
Generate correct RIDDL syntax

Usage Examples¶

Validate Current File¶

In Copilot Chat:

@workspace Validate the RIDDL file I have open

Check Model Completeness¶

@workspace What's missing from my domain model in this folder?

Generate RIDDL from Description¶

Create a RIDDL context for managing customer subscriptions with these features: monthly billing, plan changes, cancellation

Fix Errors¶

I'm getting "Undefined reference to type OrderId" - how do I fix this?

Get Suggestions¶

What should I add next to make this entity ready for implementation?

Chat Commands¶

Use Copilot Chat participants for different contexts:

Command	Description
`@workspace`	Include workspace context in query
`@vscode`	Ask about VS Code features
`/explain`	Explain selected code
`/fix`	Fix issues in selected code

Examples¶

@workspace /explain the Order entity in src/orders.riddl

@workspace /fix the validation errors in this RIDDL file

Troubleshooting¶

MCP Not Recognized¶

Verify GitHub Copilot Chat extension is installed
Check that MCP support is enabled in your Copilot subscription
Restart VS Code after configuration changes

Connection Errors¶

Test the server: curl https://mcp.ossuminc.com/health
Verify URL doesn't have trailing slashes
Check API key is correct

Tools Not Working¶

Look in Output panel > "GitHub Copilot Chat" for errors
Verify JSON syntax in settings
Try removing and re-adding the configuration

Integration with RIDDL Extension¶

When both extensions are active:

RIDDL extension provides:
Syntax highlighting
Local validation (instant feedback)
Code completion for keywords
Copilot with RIDDL MCP provides:
Deep semantic analysis
Natural language to RIDDL conversion
Error explanations
Model completeness checking
Simulation readiness analysis

Recommended Workflow¶

Use RIDDL extension for real-time syntax feedback
Use Copilot Chat for complex questions and generation
Ask Copilot to validate when making significant changes
Use check-completeness before finalizing models

Back to MCP Overview