skills

Engineering skills library — markdown SKILL.md files that plug into any AI-coding harness.

For Claude Code this repo is a plugin, installed from the marketplace it also hosts; that path carries the hooks and MCP servers too. For Crush, Pi and OpenCode it is a plain library wired by install.sh as one directory symlink per harness. See SKILLS_INDEX.md.

What is a skill?

A skill is a single directory containing one or more markdown files. The canonical entrypoint is <name>/SKILL.md. Additional reference material lives alongside in the same directory (e.g. clean-code/references/code-smells.md). Harnesses load skills on demand — keep SKILL.md short and triggerable; push depth into references.

See SKILLS_INDEX.md for the full catalogue with descriptions and "use when" triggers.

Install

Claude Code — the plugin

/plugin marketplace add https://git.d-ma.be/mathias/skills.git
/plugin install skills@mathias

The plugin ships skills, the secret-guard + pre-task-ritual hooks, and the brain/gitea/infra MCP servers as one versioned unit. Skills are namespaced (skills:tdd). Updates land when .claude-plugin/plugin.json's version moves — CI bumps it on every release.

Crush, Pi, OpenCode — install.sh

curl -fsSL https://git.d-ma.be/mathias/skills/raw/branch/main/install.sh | bash

Idempotent. It clones or fast-forwards the checkout, then populates one managed directory and gives each harness a single link to it:

Path	Target
~/.agents/skills/	a real directory, one symlink per skill (Pi reads this path directly)
~/.agents/skills/<skill>	$SKILLS_CHECKOUT_DIR/skills/<skill>, or another configured source
~/.config/crush/skills	~/.agents/skills
~/.config/opencode/skills	~/.agents/skills

Total links are N + one per harness — not N x harnesses, which is what #23 was actually about.

More than one source of skills

~/.agents/skills used to be a single link straight at this checkout. That encoded an assumption nobody had stated — that this checkout is the only source of skills on the host — and on flamingo the only way to install this library was to displace Anthropic's official set, which lived in Crush's directory. Real capability loss dressed up as a tidy-up (#27).

Point SKILLS_EXTRA_SOURCES at any number of extra directories, colon separated, each holding <skill>/SKILL.md:

SKILLS_EXTRA_SOURCES=~/.config/crush/skills.anthropic bash install.sh

• The checkout is always first and always wins a name collision — but the collision is logged, never resolved in silence. Quietly picking one is how stale content wins.
• Removing a skill from a source removes its link on the next run.
• Anything in the managed directory that is not a symlink is reported and left alone. install.sh does not delete content it did not create.
• The source list is recorded at ~/.agents/skills-sources so bin/doctor can tell a link into a known source from a link into a forgotten one.

Where the checkout must live

SKILLS_CHECKOUT_DIR defaults to ~/.local/share/skills, and that default is load-bearing: it is host-local, outside any synced or shared directory.

On this fleet ~/dev is an iCloud folder shared by flamingo and iguana, and it spans two path roots — /Users/mathias on the Macs, /home/mathias on koala. A checkout there is a git working tree with two concurrent writers, and any absolute symlink stored there is broken on one side by construction. That is what produced 243 dangling links across 12 repos (#23). Do not "fix" the default to point into ~/dev.

Per-host env-var overrides

Env var	Default
SKILLS_REPO_URL	https://git.d-ma.be/mathias/skills.git
SKILLS_REF	main (set to e.g. v0.4.0 to pin a release)
SKILLS_CHECKOUT_DIR	$HOME/.local/share/skills
SKILLS_SKIP_FETCH	unset (1 wires an existing checkout without touching HEAD)
AGENTS_SKILLS_DIR	$HOME/.agents/skills
CRUSH_SKILLS_DIR	$HOME/.config/crush/skills
OPENCODE_SKILLS_DIR	$HOME/.config/opencode/skills
SKILLS_EXTRA_SOURCES	unset (colon-separated extra source directories)

Antigravity and Mistral Vibe targets were removed — unused.

Checking a host

task doctor      # or bin/doctor

Reports dangling links, links resolving into a foreign checkout, skill-count mismatches, stray entries, and leftover per-skill Claude symlinks. Non-zero exit on drift. It also runs at session start via the plugin, so a drifting host says so rather than waiting to be discovered.

Versioning

Every commit to main is auto-tagged as a semver release by the .gitea/workflows/release.yml action. Bump direction follows the commit footer:

• Bump-Type: major → X.0.0
• Bump-Type: minor → 0.Y.0
• anything else → 0.0.Z (patch, the default)

Consumer projects can pin a version by setting SKILLS_REF=v0.1.0 before task skills:install; default is main for always-current.

Contributing a skill

1. Add a directory <short-kebab-name>/.
2. Create <short-kebab-name>/SKILL.md — start with one-paragraph purpose, then triggers ("use when …"), then mechanics.
3. Add a row to SKILLS_INDEX.md (description + use-when).
4. Commit directly to main. Conventional-commit prefix (feat: / fix: / docs:). Add Bump-Type: minor footer when adding a new skill or expanding scope; default patch covers edits.

This repo is markdown-only and public — never include secrets, client names, or anything under NDA in a skill.