AI Agent Skills by Niobium — portable SKILL.md packages that guide AI coding agents through building privacy-preserving and fully homomorphic encryption (FHE) applications. Each skill works with any agent that supports the open Agent Skills standard: Claude Code, OpenAI Codex CLI, Cursor, Gemini CLI, GitHub Copilot, Windsurf, and more.

A ten-stage methodology (Stages 0–9) for designing and building Fully Homomorphic Encryption (FHE) applications with OpenFHE (optional Niobium DSL path) — from build environment and privacy model through feasibility, scheme selection, circuit design, parameter selection, the faithful twin, encrypted implementation, and protocol specification. Use it whenever you need to compute on encrypted data, assess FHE feasibility, or structure a client–server protocol for encrypted computation.

npx skills add NiobiumInc/niobium-skills --skill fhe-application-design

Using Claude Cowork? Don't use the CLI above — it targets coding agents (Claude Code) and its --global option won't apply to Cowork. Install through Cowork's plugin UI instead: see Claude Cowork below.

Prerequisites (beyond the skill itself): building and running the encrypted application (Stage 8) happens in the prebuilt FHE-dev container — you never build OpenFHE from source. You need Docker and a one-time pull of the image (several GB):

docker pull ghcr.io/niobiuminc/fhe-dev:v0.7.0
docker run --rm ghcr.io/niobiuminc/fhe-dev:v0.7.0 fhe-smoke-test   # ends with SMOKE OK

The skill walks you through this as its Stage 0, so you can also just start a conversation and let the agent set it up with you. The design stages (1–7) need nothing installed at all.

See the skill's README for full documentation.

Each skill installs independently. Pick whichever method fits your setup — all of them install the full skill folder, including its references/.

npx skills add NiobiumInc/niobium-skills --skill <skill-name>

skills.sh auto-detects your agent and writes the skill to the right directory.

Cowork installs skills as plugins through its own UI — not the npx/gh CLIs above (those write to a coding agent's .claude/skills/, which is why they report a "Claude Code" target and offer a --global option that doesn't apply to Cowork). Add this repo as a plugin marketplace, then install the plugin:

1. Open the Cowork tab, then Customize in the left sidebar → Plugins.
2. Under Personal plugins, click + → Add marketplace → Add from a repository, and enter https://github.com/NiobiumInc/niobium-skills.
3. Click Browse plugins, find fhe-application-design, and click Install.
4. In a task, type / (or the + button) to invoke the FHEanna skill.

The FHE-dev Docker image (Stage 0) is still a separate docker pull — see Prerequisites above.

gh skill install NiobiumInc/niobium-skills <skill-name>

This repo is also a Claude Code plugin marketplace, so each skill can be installed as a plugin:

/plugin marketplace add NiobiumInc/niobium-skills
/plugin install fhe-application-design@niobium-skills

Clone the catalog and copy the skill folder (preserving references/) into your agent's skills directory:

git clone https://github.com/NiobiumInc/niobium-skills
cp -r niobium-skills/skills/<skill-name> ~/.claude/skills/<skill-name>

The installed directory name must match the skill's name frontmatter. For any agent not listed, use the npx skills add installer above or see agentskills.io.

niobium-skills/
├── README.md                          # This catalog landing page
├── LICENSE                            # Apache-2.0 (applies to all skills)
├── CONTRIBUTING.md
├── .claude-plugin/
│   └── marketplace.json               # Claude Code plugin marketplace manifest
└── skills/
    └── fhe-application-design/        # A self-contained skill (name matches its dir)
        ├── SKILL.md
        ├── README.md
        ├── references/
        └── evals/

Each skill is self-contained under skills/<name>/, with its own SKILL.md, README.md, and bundled references/. Adding a skill is one folder here plus one entry in .claude-plugin/marketplace.json.

Apache-2.0. Maintained by Niobium.