Thomas Thornton Blog

Terraform Module Design Is the Hard Part – So I Built an Agent Skill for It

Thomas Thornton — Thu, 23 Apr 2026 10:00:56 +0000

Terraform modules usually start with good intentions. A team wants consistency, there is some repeated Terraform, and a shared module feels like the obvious next step. Sometimes that instinct is right. Quite often, though, the real problems begin before anyone writes the module itself. The worst module pain rarely comes from bad HCL. It usually comes from design choices made too early or too…

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The Real Value of GitHub Copilot Rubber Duck

Thomas Thornton — Thu, 16 Apr 2026 10:30:00 +0000

The easy part of AI-assisted coding is getting code produced, and that no longer feels like the real bottleneck. What becomes harder, and much more expensive, is when an agent commits too early to a bad plan, carries the wrong assumption through a multi-file change, or produces something that looks tidy enough to pass a quick glance while still being wrong in the ways that matter.

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What Makes a Good GitHub Copilot Agent Skill?

Thomas Thornton — Mon, 13 Apr 2026 14:16:43 +0000

After building a growing set of GitHub Copilot skills across areas such as Azure API Management, infrastructure as code authoring, and diagram generation with tools like Excalidraw and Draw.io, I have found that the difference between a skill that is genuinely useful and one that quietly disappoints usually comes down to a small number of ... Read more

Packaging GitHub Copilot Agents and Skills with Agent Package Manager

Thomas Thornton — Thu, 02 Apr 2026 11:30:00 +0000

If you have been building GitHub Copilot agents and skills for any length of time, you eventually run into the same problem: creating them is the easy part. Sharing them properly is where the real friction starts. At first, the workaround feels reasonable. You build a useful agent for Terraform provider upgrades. You add a skill for architecture reviews. Maybe you create another for diagram…

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Creating Diagrams with an Excalidraw Agent Skill and Excalidraw MCP

Thomas Thornton — Tue, 24 Mar 2026 15:31:18 +0000

There is a point where diagramming starts to feel like admin. You are in the middle of thinking through an architecture, a delivery workflow, or a system interaction. The shape of it is clear enough in your head, but getting it into a diagram means stopping what you are doing, opening another tool, dragging boxes around, lining arrows up, fixing spacing, and then exporting something that will…

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Azure Pricing Skill for GitHub Copilot Using Azure MCP

Thomas Thornton — Thu, 19 Mar 2026 12:30:00 +0000

One of the things that used to slow me down when designing Azure architectures was the pricing question. You sketch out a solution, choose the services, think through HA, security, networking, and how it will land in Terraform or Bicep, and then someone asks: what does this actually cost? That is usually where the flow breaks. You alt-tab to the Azure Pricing Calculator…

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AWS Diagram Agent Skill with Draw.io MCP

Thomas Thornton — Thu, 12 Mar 2026 21:07:39 +0000

When I first built my Diagram Agent Skill with Draw.io MCP, the focus was Azure. That was deliberate. I wanted to solve one problem properly before broadening it. If you have ever tried to create a cloud architecture diagram that is both accurate and easy to read, the trade-off is familiar enough: manual drawing gives you precision but takes too long, while auto-generation is quick but often…

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Automating Terraform provider upgrades with GitHub Agentic Workflows

Thomas Thornton — Tue, 10 Mar 2026 13:55:21 +0000

Terraform provider upgrades often turn into a manual research exercise. You check the registry, read changelogs, scan the codebase for deprecated resources, update the provider version, add moved blocks, run a plan, and hope nothing breaks. Using GitHub Agentic Workflows, a Terraform MCP server, and reusable agents and skills, much of that preparation can be ... Read more

Azure Diagram Agent Skill with Draw.io MCP

Thomas Thornton — Thu, 05 Mar 2026 15:44:45 +0000

If you’ve ever tried to create a cloud architecture diagram that’s both accurate and easy to read, you’ll know the challenge: Recently, I wrote about my experience using Draw.io MCP for diagram generation – why it’s worth adopting and how it changes the way teams produce diagrams. If you haven’t read that post yet, start there for broader context: Draw.io MCP for Diagram Generation – Why…

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Draw.io MCP for Diagram Generation: Why It’s Worth Using

Thomas Thornton — Mon, 02 Mar 2026 16:39:47 +0000

I started using Draw.io MCP to generate diagrams from structured input and keep them tied to code and infrastructure. Instead of manually arranging every shape, I can now generate a solid first draft in minutes, make deliberate edits, and commit it to Git. That simple change turns diagrams into living assets rather than throwaway images ... Read more