python-pro skill (Jeffallan) for Claude Code: typed, async Python with pytest

A Python specialist skill from Jeffallan's claude-skills pack that makes Claude write typed, async-first Python and check it with mypy, black and ruff.

Installs: 8.9K; on skills.sh
Stars: 12.2K; on GitHub
Files: 5; besides SKILL.md
Updated: Oct 2026; last repo commit

python-pro makes Claude follow a five-step workflow for Python 3.11+ code: analyze the codebase, design interfaces, implement with full type hints, write a pytest suite, then run mypy --strict, black and ruff and fix what they report. It lists 8 things it must do and 7 it must not, and loads one of 5 reference files for types, async, standard library, testing or packaging.

It triggers on type hints, async/await, dataclasses, dependency injection, logging and structured error handling. It runs those tools in your project and can rewrite files with their auto-fixes. SKILL.md names no API key.

Good for

Python developers who want full type hints and strict mypy on new code
Anyone adding pytest fixtures, mocking or parametrized tests
Teams writing async I/O code with asyncio and dataclasses

Install python-pro

Claude Code

Copy this prompt.

Install the python-pro skill in Claude Code. Run this command:

/plugin marketplace add jeffallan/claude-skills
/plugin install fullstack-dev-skills@fullstack-dev-skills

Then check that it loaded and tell me how to use it.

2
Paste it into Claude Code. It shows the change and asks before running it.

Plugin route: adds the pack's 67 skills (the repo has 67) and its 10 slash commands (/common-ground and 9 project workflow commands), not only this skill. Restart Claude Code when prompted. Skills CLI route: the Quick Start says it installs skills only, without the slash commands; the --skill flag picks this one. Python 3.11 or newer and the tools the skill runs (mypy, black, ruff, pytest) must already be on your machine.

From the project README. Source.

What's in the skill

When it loads

Use when building Python 3.11+ applications requiring type safety, async programming, or robust error handling. Generates type-annotated Python code, configures mypy in strict mode, writes pytest test suites with fixtures and mocking, and validates code with black and ruff. Invoke for type hints, async/await patterns, dataclasses, dependency injection, logging configuration, and structured error handling.

Sections in SKILL.md

When to Use This Skill
Core Workflow
Reference Guide
Constraints
MUST DO
MUST NOT DO
Code Examples
Type-annotated function with error handling
Dataclass with validation
Async pattern
pytest fixture and parametrize
mypy strict configuration (pyproject.toml)
Output Templates
Knowledge Reference

Key facts

Author: Jeffallan, Principal Consultant at Synergetic Solutions (SKILL.md metadata)
License: MIT (SKILL.md frontmatter, README and plugin.json)
Version: 1.1.0 in the frontmatter
Installs on skills.sh: 8,942 as of 2026-11-02
GitHub stars: 12,161 for the whole claude-skills repo, 2026-11-02
Last change to this skill: 2026-10-30
What is inside: 6 files including SKILL.md: 5 reference files (type-system, async-patterns, standard-library, testing, packaging)
Part of: The fullstack-dev-skills plugin (67 skills and 10 slash commands in the repo)
Related skills: fastapi-expert and devops-engineer (SKILL.md related-skills)
Works in: Claude Code (plugin and skills CLI documented in the QUICKSTART)
skills.sh audits: Gen Agent Trust Hub fail, Socket pass, Snyk pass

What it includes

Reviews structure, dependencies, type coverage and the test suite.
Read · Analyze codebase
Defines protocols, dataclasses and type aliases before writing code.
Design interfaces
Writes Pythonic code with full type hints and error handling.
Write · Implement
Creates a pytest suite with fixtures and mocking, aiming above 90% coverage.
Runs code · Test
Runs mypy --strict, black and ruff, fixes what they report and re-runs them.
SKILL.md says that if mypy fails, Claude fixes the type errors and re-runs before going on, and that black or ruff issues get auto-fixes and a re-check.
Try: “Use python-pro to add type hints to utils/config.py, then run mypy --strict and fix what it reports.”
Runs code · Validate
Sets 8 rules, such as full type hints, Google-style docstrings and X | None.
MUST DO rules
Sets 7 bans, such as mutable defaults, bare except and hardcoded secrets.
MUST NOT DO rules
Loaded for type hints, mypy, generics, Protocol.
Read · references/type-system.md
Loaded for async/await, asyncio, task groups.
Read · references/async-patterns.md
Loaded for pathlib, dataclasses, functools, itertools.
Read · references/standard-library.md
Loaded for pytest, fixtures, mocking, parametrize.
Read · references/testing.md
Loaded for poetry, pip, pyproject.toml, distribution.
Read · references/packaging.md
Delivers a typed module, a pytest file, mypy confirmation and a short explanation.
Output templates

From the official docs

Permissions

Low risk

It runs Python tooling in your project and lets black and ruff rewrite files. Commit first so you can review what changed.

What it can do

Read your data
Create and change things
Delete things
Read-only mode

Watch out for

Formatters rewrite your files
SKILL.md says that when ruff or black report issues, Claude applies the auto-fixes and re-validates. Commit before you start so you can review the diff. github.com
The plugin route adds a whole pack
The fullstack-dev-skills plugin in the repo has 67 skills and 10 slash commands. The README says the workflow commands need an Atlassian MCP server. The repo has no hooks file or .mcp.json at its top level. Use the skills CLI to install python-pro alone. github.com

Technical details

Scopes	Reads your Python project and writes modules and tests Runs mypy --strict, black, ruff and pytest in your project

Questions

What does python-pro do?

It makes Claude write modern Python 3.11+ with full type hints, async/await where it fits, and a pytest suite. It then validates the result with mypy in strict mode, black and ruff.

How do I install it in Claude Code?

Use the install box above. The plugin route installs all 67 skills of the fullstack-dev-skills pack and 10 slash commands. The skills CLI or folder routes install only python-pro.

Do I need to install mypy, black, ruff and pytest?

They need to be available in your project. SKILL.md tells Claude to run them and lists no install step for them.

Does it work with Poetry, pip or uv?

SKILL.md names Poetry, pip and pyproject.toml in its packaging reference topic. SKILL.md does not mention uv.

What are the slash commands in the plugin?

There are 10: /common-ground and 9 project workflow commands. The README says the workflow commands need an Atlassian MCP server. They are not part of python-pro.

Does it work in the Claude app or Codex?

The install box has a Claude app ZIP upload for the python-pro folder. It is our generated route, not one the repo documents. The repo's own docs cover Claude Code installs and name no Codex route for this skill. The skill tells Claude to run mypy, black, ruff and pytest, so a setup with shell access fits best.

Is it safe?

It runs mypy, black, ruff and pytest in your project, and black and ruff auto-fixes rewrite your files. The plugin route also adds 66 other skills and 10 commands. Our advice: use a clean git branch, review the diff, and use the skills CLI if you want only this skill.

Information

updated Nov 2, 2026

Repository: jeffallan/claude-skills
Folder: skills/python-pro

jeffallan/claude-skills skills.sh

Sources

Docs, issue trackers and discussions this page is built from.

Show all 6

claude-skills README · github.com
claude-skills QUICKSTART · github.com
marketplace.json · github.com
plugin.json · github.com
python-pro SKILL.md · github.com
skills.sh listing · skills.sh