What does the Tomas skill do?

Write and review clean, extension-only X++: Chain of Command, event handlers, data entities, batch jobs and performance fixes. Load it once into Claude Projects and you get a configured Dynamics 365 F&O Developer (X++) without re-explaining context at the start of every session. Always build and test in a sandbox or development environment before deploying to production.

How do I install this skill file?

Download the .skill package (it contains SKILL.md), paste the contents into Claude Projects Instructions or your AI's system prompt, add your own context and start your first session. Works with Claude, ChatGPT, or any AI chat that accepts system prompts.

Which AI tools does this skill work with?

Works with Claude (recommended), ChatGPT, Gemini, Perplexity and Copilot, and any AI chat that accepts system prompts. Claude Projects gives the best results.

What is included in this download?

One .skill package delivered instantly after purchase: the full SKILL.md role configuration plus a worked-examples file with two real scenarios so you see the quality before you rely on it. No subscription, yours permanently.

How is this different from using Claude without the Tomas skill?

Without a skill file your AI starts every session as a general assistant. With Tomas loaded it applies Dynamics 365 F&O Developer (X++) methodology from the first message, with consistent quality every time. Always build and test in a sandbox before production.

Dynamics 365 F&O Developer X++ AI Skill

Name: Tomas — Dynamics 365 F&O Developer (X++) AI Skill
Brand: KissMySkills
SKU: tomas-dynamics-365-fo-developer
Price: 34.0 USD
Availability: InStock

Tomas — Dynamics 365 F&O Developer (X++) AI Skill

$34.00

Tomas — Dynamics 365 F&O Developer (X++) AI Skill

$34.00

⚡ Instant download ◆ Claude & ChatGPT ∞ Keep forever

Instant download · 30-day money-back guarantee. Pay once, keep forever — no subscription. Refund policy

Write and review clean, extension-only X++: Chain of Command, event handlers, data entities, batch jobs and performance fixes.

Extension model: Chain of Command, event handlers, no overlayering
X++ data model: tables, EDTs, enums, indexes, relations
Data entities (OData/DMF) and SysOperation batch jobs
Set-based performance (insert_recordset) and deployable packages

D365 F&O X++ developers and technical consultants who want correct, extension-only code and reviews.A senior D365 F&O developer bills $110+/hr, this is one file, yours forever.

// what's inside

Drop Tomas into Claude and get a senior Dynamics 365 F&O developer who writes clean X++ the modern way, extensions and Chain of Command, never overlayering, set-based and testable.

Tomas checks for a standard or extension point first, then extends with Chain of Command or event handlers, writes set-based X++, and packages it properly. X++, data entities, SysOperation batch, forms, performance (insert_recordset), Visual Studio deployable packages and LCS. Always test in a dev or sandbox before deploying a package.

What you get

→Extension model: Chain of Command, event handlers, no overlayering
→X++ data model: tables, EDTs, enums, indexes, relations
→Data entities (OData/DMF) and SysOperation batch jobs
→Set-based performance (insert_recordset) and deployable packages

📄 tomas-dynamics-365-fo-developer.skill Under 2 min install Works with Claude, ChatGPT & any AI chat

How to install

Download the .skill package → open Claude → paste SKILL.md into your Project Instructions or system prompt → describe your requirement → Tomas builds the answer. Includes a full worked example (two real scenarios) so you see exactly what you get.

tomas-dynamics-365-fo-developer.skill

# Tomas — Dynamics 365 F&O Developer (X++)

You are Tomas, a senior D365 F&O X++ developer. You check for a standard/extension point, extend never overlayer, write set-based X++, test, then package.

## How you work
1. Confirm the requirement; find the extension point first
2. Extend with Chain of Command / event handlers (no overlayering)
3. Write set-based, testable X++
4. Add a SysTest test; build a deployable package

Always test in a dev/sandbox environment before deploying to production.

Excerpt from the actual file you'll download.

// try it

prompt

$Add validation before a sales order is posted using an extension, without overlayering, and show me the code and a test.

Tomas returns a Chain of Command or event-handler extension with the X++ code, why it avoids overlayering, and a SysTest test class, plus how to build it into a deployable package.

// how to install Under 2 minutes

Four steps. Any AI chat.

01
Download the file
After checkout, the download link lands in your inbox. Save the file anywhere on your device.
02
Open your AI chat
Claude, ChatGPT, Gemini, Grok, or Copilot — whichever one you already use.
03
Paste the file contents
Drop it into the system prompt, Project instructions, or custom instructions field.
04
Start working
Your AI is now configured as a specialist. Ask it anything inside its domain.