fstack, the simple stack

Jul 13, 2026

I built my own agent skill collection: 13 skills, plain names, one job each. Here's why it exists and how it works.

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I built my own agent skill collection. It’s called fstack. The f stands for Flavio.

You can install it right now:

npx skills@latest add flaviocopes/fstack

It works with Cursor, Claude Code, Codex — anything that reads skills.

Why another stack

There are a lot of skill collections around. I studied several of them, and I borrowed ideas from all of them.

But they kept growing. 30+ skills, personas, pipelines, voice triggers. I couldn’t hold them in my head, so I stopped using them.

And here’s the thing I noticed: the complexity doesn’t stay in the workflow. A process built to sound smart — phases, personas, ceremony — produces code that sounds smart too. Layers, abstractions, options nobody asked for.

fstack is my response to that. Agent skills that ask: can this be less?

The core loop

fstack is 13 skills. Plain names, one job each.

Five of them form the core loop:

fstack-nail → fstack-plan → fstack-build → fstack-check → fstack-push

/fstack-nail asks up to 5 questions and turns a vague idea into a 3-line summary you approve
/fstack-plan writes a one-page plan with a mandatory “what we’re NOT doing” section
/fstack-build implements the plan one small step at a time, asking at real choices
/fstack-check asks three questions: does it work, does it match the plan, is it simple
/fstack-push commits and pushes. Nothing else.

Notice the loop ends with a push. I commit and push to the branch I’m on, and that’s it. fstack reflects how I actually work.

Before you write code

Two skills run before any code exists.

/fstack-roast stress-tests a product idea. It asks you multiple-choice questions about demand, competition, and distribution, then gives you a verdict and the smallest version worth building. Honest pushback before you waste a weekend.

/fstack-interview interviews you about the business behind the project — who the customer is, how they find you, what they pay — and records the answers in AGENTS.md. From then on, every agent session knows the context instead of guessing it.

The skill I care most about

/fstack-simplify exists only to remove things.

Point it at a file, or at the whole codebase. It finds unnecessary abstractions, dead configuration, wrappers around wrappers, and proposes deletions. Only deletions. It never adds.

I don’t know another stack with a skill whose entire job is removing code. To me it’s the most important one.

The rest

A few more you sprinkle in when needed:

/fstack-design — when AI-generated UI drifts from your existing styles, this pulls it back
/fstack-document — writes layered docs for the project, from ELI5 to deep. Run it again to update them
/fstack-learn — captures one lesson in three lines, so future sessions start smarter
/fstack-counselors — sends the same question to the 3 most capable models available and synthesizes one verdict, including where they disagree

And if you don’t know where to start, type /fstack alone. It lists every skill and picks the right one for what you describe.

The human drives

Every fstack skill pauses at decision points and asks. You approve, it executes.

No long autonomous runs. No agent disappearing for an hour and coming back with 4,000 changed lines. Small steps, small diffs, your judgment in the loop.

That’s the whole philosophy. Short skills, plain names, no jargon, prefer deletion. Every skill fits in about 150 lines. If it doesn’t, it’s doing too much.

Try it

npx skills@latest add flaviocopes/fstack

The code is on GitHub, MIT licensed.

I wrote a full guide with examples for every skill at cookwithai.dev/fstack.

fstack distills ideas from gstack, pstack, Compound Engineering, Matt Pocock’s skills, and Aaron Francis’s counselors. Credits and links are in the guide — they’re all generous, thoughtful work.

Tagged: AI · All topics

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