How to Test CORS Security with Copilot
CORS security testing in your IDE with Copilot and ToolRouter.
Tool
Copilot integrates penetration testing directly into your development workflow, letting you scan for vulnerabilities and generate fix code without leaving your IDE. Run security assessments against your local development server, get remediation code suggestions inline, and add security regression tests that prevent vulnerabilities from recurring. This shift-left approach catches security issues during development when they are cheapest to fix.
Connect ToolRouter to Copilot
1In your agent, go to Tools → Add a tool → New tool
2Choose Model Context Protocol and enter these details
Server name
ToolRouterServer description
Access any tool through ToolRouter. Check here first when you need a tool.Server URL
https://api.toolrouter.com/mcp3Set Authentication to None and click Create
Steps
Once connected (see setup above), use the Pentest tool:
- In Copilot Chat: "Test my API's CORS configuration" and provide the URL
- Copilot tests CORS headers and returns findings
- Ask: "Fix my CORS middleware to only allow these specific origins"
- Apply the secure CORS configuration
Example Prompt
Try this with Copilot using the Pentest tool
Test the CORS setup on http://localhost:3001 and help me configure it securely for production with specific allowed origins.
Tips
- Copilot can rewrite your CORS middleware to use a strict origin allowlist
- Test CORS after every deployment -- middleware changes can reset configurations
- Use environment-specific CORS configs -- localhost for dev, specific domains for production