What is the difference between spec-kit and co-pilot instruction files?

[ssabzevari-antuit]

I am already using co-pilot global and specific instruction file to do the same thing. In global we have equivalent of the constitution and tasks are defined as custom instruction file.

I am wondering what else spec-kit will add on top of that?

[anchildress1]

The constitution is just one tiny part of the overall setup. So assuming you already have a pretty well-defined instructions file, what I would do is lift and shift that over to AGENTS.md, which copilot will pick up most of the time if you're using VS Code anyway. For everything else, you can wire your copilot-instructions.md with a link to AGENTS and it will treat them the same from there.

Now for your answer about Spec Kit in general, the great thing about this guy is the ability to plan a feature with minimal setup or prompting and end up with a full step by step action plan that any model can implement (in most cases anyway). The prompts for creating a spec, iterating through tasks, and clarifying the entire flow up front is a brilliant process that can inherently point out a lot of gaps in an idea before it ever gets close to any code.

Now that being said, you're also going to want to use one of the high-end models to create those specs for you which can burn through limits depending on your setup. You can compensate for that in some cases by using the smaller models for actual implementation because at that point your tasks are prioritized and sufficiently detailed that even Grok can handle most of that part just fine.

Spec Kit doesn't always fit my workflow either, but when it does make sense—it is absolutely spectacular at what it does!