Practical Ways to Use GitHub Copilot for X++ Development (Tips, Tricks, Hidden Gems & What to Avoid)

Hi Folks, 

In my last post about GitHub Copilot we covered what GitHub Copilot is, how to enable it, and the licensing options, let’s move into the part everyone actually cares about — Practical Ways to Use GitHub Copilot for X++ Development

Copilot isn’t magic, but when used well, it feels pretty close. Below are practical examples, prompt ideas, best practices, and a few “don’ts” that will save you time and frustration.

1. X++ Boilerplate Generation (Your New Time Saver)

X++ is full of repetitive patterns — table methods, service classes, form event handlers, data entities, and more. Copilot can generate 60–80% of this instantly.

Try prompts like:

• “Create a validateWrite method for this table following best practices.”
• “Generate a runnable class that updates sales orders with status ‘Open’.”
• “Create a SysOperation framework class with contract, controller, and service.”

You still review and refine — but the heavy lifting is done. (I would still recommend this to do every single time)

2. Documentation & XML Comments (The Most Underrated Feature)

Copilot is brilliant at generating XML documentation for methods, classes, and services.

Prompt idea:

• “Add XML documentation to this method explaining parameters and return values.”

Why it matters

• Better readability
• Faster onboarding for new developers
• Cleaner code reviews

3. OData & Integration Summaries

When working with integrations, Copilot can help you quickly draft:

• OData endpoint descriptions
• Request/response examples
• Error-handling notes
• API documentation

Prompt idea:

• “Explain how this data entity will behave when called via OData.”

This is especially useful when writing technical design documents.

4. Best Practice Suggestions on Selected Code

This is where Copilot becomes a mini code reviewer.

Highlight a block of X++ code → open Inline Chat (Alt + /) → ask:

• “Suggest best practices for this code.”
• “Is there any performance issue here?”
• “Rewrite this using recommended patterns.”

Example: Summarize Sales Order

Your example:

public void summarizeSalesOrder(str salesOrderId)

{

    SalesTable salesTable = SalesTable::find(salesOrderId);

    info(strFmt("Sales Order %1 for customer %2 has total amount %3",

        salesTable.SalesId, salesTable.CustAccount, salesTable.TotalAmount));

}

Copilot might suggest:

• Add null checks
• Use ttsbegin/ttscommit if modifying data
• Avoid info() in production code
• Consider using SalesTotals class for accurate totals

This is where Copilot shines — it nudges you toward better patterns.

5. Plugin Development with Copilot Studio

If you’re building Copilot plugins for D365FO, Copilot can help with:

• API schema generation
• JSON payload examples
• C# wrapper classes
• Error-handling templates

This is still evolving, but it’s already a huge productivity boost.

6. Hidden Gems Most Developers Miss

•       Use #filename to give Copilot context

Example:

#SalesTable Explain how validateWrite works for this table.

• ü      Use /intent to guide Copilot

Example:

/refactor Rewrite this method to improve readability.

• ü  Keep related files open

Copilot reads open tabs to understand your project structure.

• ü  Use natural language

You don’t need to be formal.
“Make this faster” works surprisingly well.

7. What NOT to Do with Copilot (Important!)

Copilot is powerful, but not perfect. Avoid:

❌ Blindly accepting code

Always review for:

• Security issues
• Performance problems
• Deprecated APIs

❌ Using Copilot for business logic decisions

Copilot doesn’t know your customer’s requirements.

❌ Expecting Copilot to understand custom frameworks

It learns from your codebase over time — but not instantly.

❌ Using vague prompts

“Fix this” → not helpful
“Optimize this query to reduce DB calls” → much better

While all this working magically, GitHub Copilot won’t replace your X++ expertise — but it will absolutely amplify it. So don't afraid of using it, make this your companion. The more you use it, the better it understands your patterns, naming conventions, and coding style.

-Harry 

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