What are Claude Code skills?

Skills are folders of written instructions, each with a SKILL.md file, that Claude Code reads when they are relevant to the task. They live in .claude/skills inside a project or in your home folder, and most can also be started as a slash command.

pstack is a free, MIT-licensed set of 51 Claude Code skills by Lauren Tan (poteto) that makes the agent plan, check and explain its work like an experienced engineer. Start with /poteto-mode. The source is at github.com/backnotprop/pstack.

Do skills work with Codex, Copilot or Gemini?

Skills in the .claude/skills folder are a Claude Code feature, so Claude Code is where they work fully. Other agents may read similar instruction files in their own formats, but VybeCoding's Skills sheet is aimed at Claude Code.

Will installing a skill change my code?

No. VybeCoding only writes the skill's files into the project's .claude/skills folder. It never edits, moves or deletes anything else in your project, and it refuses to overwrite a skill folder you created yourself.

Do I need to pay for skills?

No. pstack and Architecture-first engineering are free, and adding skills is part of the free VybeCoding desktop and phone apps.

2026-10-117 min read

Claude Code Skills Explained, and How to Add pstack in One Tap

What Claude Code skills are, why they make AI-built apps better, and how to add pstack's 51 commands or Architecture-first engineering from your phone.

#claude-code-skills
#pstack
#ai-coding-agents
#claude-code
#vibe-coding
#prompt-engineering

Ask an AI coding agent to add a feature and it will usually manage it. Ask it to add a feature without breaking anything else, without rewriting code you did not mention, and with a plan you can check first, and the results depend heavily on how it has been told to work. That is what skills are for. A skill is a short set of written instructions the agent reads when it is relevant, and the right skills turn a fast but careless assistant into something much closer to a careful engineer. VybeCoding now lets you add them to a project from your phone, with a plain-English explanation of each one before you do.

What a Claude Code skill is

A skill is a folder containing a file called SKILL.md: a name, a one-line description of when to use it, and the instructions themselves. Some skills also bring reference notes or small scripts. Claude Code looks in two places for them, a .claude/skills folder inside your project, which applies only to that project, and the same folder in your home directory, which applies to every project on your computer. The agent reads each skill's description up front and loads the full instructions only when the task calls for them, so adding skills does not slow it down or clutter every conversation. Most skills can also be started on purpose by typing their name as a slash command, such as /architect.

Why skills matter when the AI does the typing

An AI agent's habits are only as good as its instructions. Left alone, agents tend to rush straight into code, fix symptoms rather than causes, and helpfully tidy up things nobody asked them to touch. An experienced engineer avoids those mistakes out of habit. Skills write those habits down so the agent follows them every time. If you are building an app by describing it rather than by writing code, skills are the closest thing you have to a senior engineer looking over the AI's shoulder.

pstack: 51 commands from an experienced engineer

pstack is a free, open source collection of skills by Lauren Tan, known online as poteto, shared under the MIT licence at github.com/backnotprop/pstack. It packages one engineer's way of working into 51 commands. /poteto-mode switches the agent into pstack's careful, tidy way of working and is the place to start, and /poteto-help suggests the right command if you describe your task in your own words. /architect sketches the plan and structure before any code is written. /blast-radius finds what else a change might break before you ship it. /interrogate has several AI reviewers try to find problems in a change. /how and /why explain how part of your app works and why it was built that way, and /bro repeats the last answer in plain English. There are also 24 short principles, such as /principle-fix-root-causes and /principle-prove-it-works, that the agent can follow when a situation calls for them.

Architecture-first engineering

Alongside pstack, VybeCoding includes its own skill, Architecture-first engineering. It makes the agent behave like a careful engineer working on an app that already exists: read and understand the code before touching it, make the smallest change that does the job, keep apps that share behaviour, such as an iPhone and an Android version, in step, and say how it checked the change works. You do not need to do anything once it is installed, because the agent uses it by itself whenever you ask for a change. It is the skill VybeCoding itself is built with.

How to add skills from your phone

You need the free VybeCoding desktop app on your Mac or Windows PC and the VybeCoding app on your iPhone or Android phone. When you create a new project from the phone, VybeCoding offers a list of skills for it. Tap the i button next to any skill to read what it does in plain English, tick the ones you want, and tap Add. For an existing project, open a session in it and tap the sparkle button at the top of the terminal to open Skills. Each skill can be installed for just this project or for every project on your computer, and the app shows whether it is installed and whether an update is available. VybeCoding only ever writes into the project's .claude/skills folder, never touches the rest of your project, and will not overwrite a skill you made yourself with the same name.

Which skills to start with

If you are new to building with AI, add Architecture-first engineering to every project, since it quietly prevents the most common way AI agents break working apps. Add pstack when you start taking on bigger changes, and begin with /poteto-mode and /architect before you ask for anything large. You do not need to learn all 51 commands. The plain-English page for each skill in VybeCoding lists every command with a one-line explanation, so you can come back to it when a situation comes up.

faq

Frequently asked questions

What are Claude Code skills?: Skills are folders of written instructions, each with a SKILL.md file, that Claude Code reads when they are relevant to the task. They live in .claude/skills inside a project or in your home folder, and most can also be started as a slash command.
What is pstack?: pstack is a free, MIT-licensed set of 51 Claude Code skills by Lauren Tan (poteto) that makes the agent plan, check and explain its work like an experienced engineer. Start with /poteto-mode. The source is at github.com/backnotprop/pstack.
Do skills work with Codex, Copilot or Gemini?: Skills in the .claude/skills folder are a Claude Code feature, so Claude Code is where they work fully. Other agents may read similar instruction files in their own formats, but VybeCoding's Skills sheet is aimed at Claude Code.
Will installing a skill change my code?: No. VybeCoding only writes the skill's files into the project's .claude/skills folder. It never edits, moves or deletes anything else in your project, and it refuses to overwrite a skill folder you created yourself.
Do I need to pay for skills?: No. pstack and Architecture-first engineering are free, and adding skills is part of the free VybeCoding desktop and phone apps.

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