AI skills for coding agents

The toolkit ships Agent Skills: small folders of instructions that teach a coding agent this ecosystem, meaning the SDK, the manifest and the CLI. They follow the open Agent Skills format, so the same folder works in Claude Code, Cursor, Codex, Antigravity, GitHub Copilot and Gemini CLI. They are versioned with the toolkit, so they describe exactly the SDK and commands you have installed.

minikit skills install                 # for every agent below
minikit skills install --agent cursor  # for one agent
minikit skills list                    # what is where, and whether it is current

How a skill works

A skill is a folder with a SKILL.md file. The file starts with a name and a description that says what the skill covers and when to use it. The rest is the instructions, and a skill may carry extra reference files next to it.

Agents load skills in three steps, so installed skills cost almost nothing until they are needed:

At the start of a session the agent reads only each skill's name and description.
When your request matches a description, it reads that skill's instructions.
It opens the skill's other files only if the task needs them.

The skills that ship

Skill	What it teaches	The agent uses it when you
`mini-app-sdk`	`MiniAppSdk.connect()`, the typed clients (app, auth, storage, files, share), errors as values with `Outcome`, permissions, `LocalHost` for tests	write or review code in a mini app
`mini-app-manifest`	`web/miniapp.json` schema 2: fields, rules, permission names, legacy capabilities, the `MK1xxx` codes	edit the manifest, migrate a Studio-era one, or fix a `minikit validate` error
`minikit-cli`	every command, its flags, exit codes and the `--json` envelope	run or automate the workflow, write CI, or chase a failing command

Try a request such as "add a screen that picks a receipt with sdk.files and shows its name". The agent loads mini-app-sdk, uses the typed client, handles the Err case and declares the files permission.

Install them

minikit create installs every skill for every agent, unless you pass --no-skills. For an existing project, or to change the list of agents:

minikit skills install                          # every skill, every agent
minikit skills install -a cursor -a codex       # only these agents (or: -a cursor,codex)
minikit skills install mini-app-sdk             # one skill
minikit skills install --scope user             # in your home folder, for every project
minikit skills install --dry-run                # show what would be written

--agent accepts claude, cursor, codex, antigravity, copilot, gemini and all. Installing again replaces the copies with the ones from your toolkit version.

Where each agent looks

Agents read each other's folders, so minikit writes the fewest folders that cover the agents you choose. In a project, all six agents need two folders: .agents/skills and .claude/skills.

Agent	Reads in a project	Reads in your home folder
Claude Code	`.claude/skills`	`~/.claude/skills`
Cursor	`.agents/skills`, `.cursor/skills`, `.claude/skills`, `.codex/skills`	the same four under `~`
Codex	`.agents/skills`	`~/.agents/skills`
Antigravity	`.agents/skills` (older versions: `.agent/skills`)	`~/.gemini/config/skills`
GitHub Copilot	`.github/skills`, `.claude/skills`, `.agents/skills`	`~/.copilot/skills`, `~/.agents/skills`
Gemini CLI	`.agents/skills`, `.gemini/skills`	`~/.agents/skills`, `~/.gemini/skills`

You choose	minikit writes	Read by
every agent (the default)	`.agents/skills` and `.claude/skills`	all six
`claude`	`.claude/skills`	Claude Code, Cursor, GitHub Copilot
`cursor`, `codex`, `antigravity`, `copilot` or `gemini`	`.agents/skills`	Cursor, Codex, Antigravity, GitHub Copilot, Gemini CLI
every agent, `--scope user`	`~/.agents/skills`, `~/.claude/skills`, `~/.gemini/config/skills`	all six

Cursor and GitHub Copilot read both project folders, so with the default they find two identical copies of each skill. To keep one copy, install for claude only when nobody uses Codex, Antigravity or Gemini CLI.

The Antigravity command-line tool keeps its user skills in ~/.gemini/antigravity-cli/skills. Copy them there by hand if you use it.

Use them

You rarely need to name a skill: agents pick one when the request matches its description. To name one explicitly:

Claude Code: type /mini-app-sdk.
Cursor: type / in the Agent chat and choose the skill. Customize → Skills lists every skill Cursor found.
Codex: mention it as $mini-app-sdk.
Antigravity, GitHub Copilot, Gemini CLI: describe the task; they load matching skills on their own.

Keep them current

minikit skills list shows each copy as one of four states:

Status	Meaning
current	installed from this toolkit version, unchanged
stale	installed from an older toolkit version
modified	edited after it was installed
missing	not installed in that folder

After minikit upgrade, run minikit upgrade --project. It refreshes stale copies in the folders they are in and leaves edited copies alone. minikit skills install replaces edited copies too.

Commit the skill folders. Teammates and CI agents then get the same skills. The install records live in the git-ignored .minikit/stamps.json. A fresh clone still shows its copies as current while they match the toolkit.

Write your own

Put team-specific knowledge in a skill of your own, for example .agents/skills/payslip-rules/SKILL.md. Follow the format's rules:

name: lowercase letters, digits and hyphens, up to 64 characters, the same as the folder name.
description: what the skill covers and when to use it, up to 1024 characters. Agents choose skills by this text alone.
Keep SKILL.md under about 500 lines and move long reference material into files beside it.

minikit only touches the folders of the skills it ships, so your own skills stay as they are. To improve a toolkit skill for everyone, edit skills/<name>/ in the toolkit repository. The change ships with the next release.