Simple Explanation of LLM's, Coding Agents

      GitHub Copilot, Claude Code, and Cursor are not AI models!  They are Coding Agents/Assistants.

They are the developer experience layer that sits in your IDE and seamlessly accesses various Large Language Models (LLMs) such as Claud Opus/Fable/Sonnet/Haiku or GPT5.

The actual intelligence comes from the underlying Large Language Model (LLM) such as GPT-5, Claude Opus/Sonnet, Gemini, 

Naming breakdown:

  VS Code / Visual Studio /Claude Code (IDE)    

      ─────▼────

GitHub Copilot / Cursor Extension / Claude Code Extension        (Coding Agent)      

      ─────▼────

 GPT-5 / Claude Opus / Gemini (LLMs)

Local vs Premium LLMS: 

Cursor can reference online LLMs like Claude Opus and use Ollama to run Qwen3-Coder (my pref. for now), DeepSeek-Coder, Llama 3.x, Mistral.  Ollama lets me point to a local LLM and use it for free (saving on tokens; there are other advantages as well).

My Setup for local LLM usage:

VS Code                                   +

Cursor Extension                     +

Ollama                                     +

Local LLM (Qwen3-Coder)    = 🚀 AI-Powered Software Development

GitHub Copilot with Claude Sonnet 4 is amazing, and GPT 5 is even better

I couldn't sleep, so I decided to build a Pulumi C# application that uses an existing MCP Server. My forms will utilise the client to allow me to access my Azure subscriptions and resources - wow.  Build a really cool tool quickly - Claude Sonnet 4 is once again significantly better than GPT-4.1 for programming with GitHub Copilot.

Update Sept 2025: I'm now using GPT-5 over Claude Sonnet with GitHub Copilot when programming in VS Code.  Both feel about the same quality to me.

GitHub have this for comparing AI models for GHCP, which is very useful.

I am using GPT-5-Codex, which "is a version of GPT-5 optimised for agentic coding in Codex".

I am also really liking GitHub Copilot code review

Anthropic's Claud 4.5 Opus is also excellent.