# Python Pro

> Use when writing Python 3.12+ — typed application code, async programming, CLI tools (cyclopts, rich), or pandas data manipulation.

- **Type:** Skill
- **Install:** `agentstack add skill-yassimba-loom-python-pro`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [Yassimba](https://agentstack.voostack.com/s/yassimba)
- **Installs:** 0
- **Category:** [Data & Analytics](https://agentstack.voostack.com/c/data-and-analytics)
- **Latest version:** 0.1.0
- **License:** Apache-2.0
- **Upstream author:** [Yassimba](https://github.com/Yassimba)
- **Source:** https://github.com/Yassimba/loom/tree/main/skills/python-pro

## Install

```sh
agentstack add skill-yassimba-loom-python-pro
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Python Pro

Type-safe, async-first, production-ready Python 3.12+: application code, CLI tools, and pandas data work.

## References

**Load the matching reference when your task touches its area** — each holds the rules and gotchas for that branch, only what the defaults get wrong.

| Reference                    | Load When                                             |
| ---------------------------- | ----------------------------------------------------- |
| `references/type-system.md`  | Generics, Protocol, type aliases, exhaustiveness      |
| `references/cli.md`          | Building or extending a CLI                           |
| `references/pandas-gotchas.md` | Any DataFrame work — cleaning, groupby, merge, perf |

Packaging and tooling have dedicated skills: use **uv** for projects/dependencies, **ty** for type checking, **ruff** for lint/format.

## Rules — General Python

- Type hints on every function signature and class attribute; `X | None` over `Optional[X]`; PEP 695 generics (`type X = ...`, `class C[T]:`, `def f[T]:`).
- Dataclasses over hand-written `__init__`; context managers for resource handling; `pathlib` over `os.path`.
- `async`/`await` for I/O-bound work; route blocking calls through `asyncio.to_thread`.
- Catch specific exception types.
- Keep default arguments immutable — a `None` sentinel for mutable defaults.
- Google-style docstrings on public APIs.

## House opinions

- **Guard clauses over nesting**: validate and return/raise early at the top of the function; the happy path reads straight down at one indent level. An `else` after a guard is a smell.
- **`TaskGroup` over bare `gather`** for structured concurrency; `asyncio.timeout()` over `wait_for`.
- **Parametrize over copy-paste tests**; property-based (hypothesis) where the invariant is crisper than examples.

## The green gate

Ship the implementation and its pytest suite together. The work is **green** when all three pass:

```bash
uv run ty check                                  # zero errors
uv run ruff check --fix && uv run ruff format
uv run pytest --cov                              # >90% coverage
```

Finish only on green.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [Yassimba](https://github.com/Yassimba)
- **Source:** [Yassimba/loom](https://github.com/Yassimba/loom)
- **License:** Apache-2.0

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** yes
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-yassimba-loom-python-pro
- Seller: https://agentstack.voostack.com/s/yassimba
- Browse the marketplace: https://agentstack.voostack.com/browse

---
Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.