tiangolo-library-skills

# Library Skills > Skill by [ara.so](https://ara.so) — Daily 2026 Skills collection. Library Skills lets AI coding agents use libraries as intended — always up to date. Libraries (e.g. FastAPI, Streamlit) embed official AI skills in each release, and `library-skills` discovers those installed packages and wires their skills into your project's `.agents` directory as symbolic links. When you upgrade a library, its skills update automatically. --- ## Installation & Quick Start No global install required. Run directly with `uvx` (Python) or `npx` (JavaScript/TypeScript): ```bash # Python projects uvx library-skills # JavaScript/TypeScript projects npx library-skills ``` For Claude Code (which doesn't yet support the standard `.agents` directory): ```bash uvx library-skills --claude # Also installs into .claude/skills in addition to .agents ``` --- ## What It Does 1. Scans your project's installed dependencies (e.g. from the active virtualenv or `node_modules`) 2. Finds libraries that publish their own skills at [agentskills.io](https://agentskills.io) 3. Prompts you to select which skills to install 4. Creates symbolic links under `.agents/` (and optionally `.claude/skills/`) pointing into the installed package Because they are symlinks, upgrading the library (e.g. `pip install -U fastapi`) automatically updates the skill content — no need to re-run `library-skills`. --- ## CLI Reference ```bash uvx library-skills [OPTIONS] ``` | Option | Description | |--------|-------------| | `--claude` | Also install skills in `.claude/skills/` for Claude Code compatibility | | `--help` | Show help message and exit | --- ## Directory Structure After Installation ``` my-project/ ├── .agents/ │ └── fastapi -> /path/to/venv/lib/python3.x/site-packages/fastapi/skills/ ├── .claude/ │ └── skills/ │ └── fastapi -> /path/to/venv/lib/python3.x/site-packages/fastapi/skills/ ├── src/ │ └── main.py └── pyproject.toml ``` --- ## Python Project Workflow ### 1. Create and activate a virtualenv with your dependencies ```bash uv venv source .venv/bin/activate uv add fastapi streamlit ``` ### 2. Run library-skills ```bash uvx library-skills # → Scans .venv, finds fastapi, streamlit with embedded skills # → Prompts: Install fastapi skills? [Y/n] # → Creates .agents/fastapi -> .venv/lib/.../fastapi/skills/ ``` ### 3. For Claude Code users ```bash uvx library-skills --claude # → Creates .agents/fastapi AND .claude/skills/fastapi ``` --- ## JavaScript/TypeScript Project Workflow ### 1. Install dependencies ```bash npm install # or pnpm install ``` ### 2. Run library-skills ```bash npx library-skills # or with Claude support npx library-skills --claude ``` --- ## Real Code Example: FastAPI with Up-to-Date Skills After installing FastAPI skills, your agent will use current patterns, not deprecated ones. ```python # main.py — agent uses skills to write correct, modern FastAPI code from fastapi import FastAPI from pydantic import BaseModel app = FastAPI() class Item(BaseModel): name: str price: float @app.get("/items/{item_id}") async def read_item(item_id: int, q: str | None = None): return {"item_id": item_id, "q": q} @app.post("/items/") async def create_item(item: Item): return item ``` With skills installed, the agent reads the embedded SKILL.md from the FastAPI package and applies the documented patterns — including any new features added in the latest release. --- ## How Library Authors Publish Skills If you are a library author who wants to embed skills in your package: 1. Create a `skills/SKILL.md` (or similar) inside your package directory 2. Publish the package to PyPI or npm 3. Register at [agentskills.io](https://agentskills.io) so `library-skills` can discover it ``` my-library/ ├── my_library/ │ ├── __init__.py │ └── skills/ │ └── SKILL.md ← embedded skill, shipped with every release ├── pyproject.toml └── README.md ``` --- ## Common Patterns ### Re-running after upgrading libraries Skills update automatically via symlinks. But if you add new libraries that have skills, re-run: ```bash uvx library-skills ``` ### Committing `.agents/` to version control Symlinks can be committed so the whole team benefits: ```bash git add .agents/ git commit -m "Add library skills for fastapi" ``` Teammates need the same virtualenv path for symlinks to resolve, so consider using relative symlinks or documenting the setup. ### Checking which skills are installed ```bash ls -la .agents/ # fastapi -> /home/user/project/.venv/lib/python3.12/site-packages/fastapi/skills # streamlit -> /home/user/project/.venv/lib/python3.12/site-packages/streamlit/skills ``` --- ## Troubleshooting ### `uvx library-skills` finds no skills - Make sure you have a virtualenv activated (or the packages are installed in the current environment) - The library must ship its own skills — not all libraries do yet; check [agentskills.io](https://agentskills.io) ### Symlinks are broken after moving the project Symlinks are absolute by default. Re-run `uvx library-skills` from the new location to recreate them. ### Claude Code doesn't load skills from `.agents/` Use the `--claude` flag to also install into `.claude/skills/`: ```bash uvx library-skills --claude ``` ### Skills are stale after `pip install -U fastapi` Skills update automatically via symlinks — no action needed. If they don't, verify the symlink target points into the virtualenv: ```bash readlink .agents/fastapi ``` --- ## Key Concepts | Concept | Explanation | |---------|-------------| | **Library Skill** | A `SKILL.md` (or similar file) shipped inside a library package | | **`.agents/` directory** | Standard location where agent skills are discovered by AI coding tools | | **Symlink** | `library-skills` uses symlinks so skills stay in sync with installed library version | | **agentskills.io** | Registry of libraries that publish agent skills | | **`--claude`** | Flag to also populate `.claude/skills/` for Claude Code compatibility | --- ## Links - **Documentation**: [https://library-skills.io](https://library-skills.io) - **Source Code**: [https://github.com/tiangolo/library-skills](https://github.com/tiangolo/library-skills) - **Skills Registry**: [https://agentskills.io](https://agentskills.io) - **PyPI**: [https://pypi.org/project/library-skills](https://pypi.org/project/library-skills) - **npm**: [https://www.npmjs.com/package/library-skills](https://www.npmjs.com/package/library-skills)