Agent skill
python-dev
Opinionated Python development setup with uv + ty + ruff + pytest + just. Use when creating new Python projects, setting up pyproject.toml, configuring linting, type checking, testing, or build tooling. Triggers on "python project", "uv init", "pyproject.toml", "ruff config", "ty check", "pytest setup", "justfile", "python linting", "python formatting", "type checking python".
Install this agent skill to your Project
npx add-skill https://github.com/tenequm/skills/tree/main/skills/python-dev
Metadata
Additional technical details for this skill
- version
- 0.1.1
SKILL.md
Python Development Setup
Opinionated, production-ready Python development stack. No choices to make - just use this.
When to Use
- Starting a new Python project
- Modernizing an existing project (migrating from pip/poetry/mypy/black/flake8)
- Setting up linting, formatting, type checking, or testing
- Creating a Justfile for project commands
- Configuring pyproject.toml as the single source of truth
The Stack
| Tool | Role | Replaces |
|---|---|---|
| uv 0.10+ | Package manager, Python versions, runner | pip, poetry, pyenv, virtualenv |
| ty | Type checker (Astral, Rust) | mypy, pyright |
| ruff | Linter + formatter | flake8, black, isort, pyupgrade |
| pytest | Testing | unittest |
| just | Command runner | make |
Quick Start: New Project
# 1. Create project with src layout
uv init --package my-project
cd my-project
# 2. Pin Python version
uv python pin 3.13
# 3. Add dev dependencies
uv add --dev ruff ty pytest pytest-asyncio pre-commit
# 4. Create Justfile (see template below)
# 5. Configure pyproject.toml (see template below)
# 6. Run checks
just check
pyproject.toml Template
This is the single config file. Copy this and adjust [project] fields.
[project]
name = "my-project"
version = "0.1.0"
description = "Project description"
readme = "README.md"
requires-python = ">=3.13"
license = {text = "MIT"}
dependencies = []
[project.scripts]
my-project = "my_project:main"
[dependency-groups]
dev = [
"ruff>=0.7.0",
"ty>=0.0.1a32",
"pytest>=8.0.0",
"pytest-asyncio>=1.0.0",
"pre-commit>=3.0.0",
]
[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"
[tool.hatch.build.targets.wheel]
packages = ["src/my_project"]
# =============================================================================
# RUFF - Loose, helpful rules only
# =============================================================================
[tool.ruff]
target-version = "py313"
line-length = 100
[tool.ruff.lint]
select = [
"E", # pycodestyle errors - syntax issues
"F", # pyflakes - undefined vars, unused imports
"I", # isort - import sorting
"UP", # pyupgrade - modern Python syntax
]
ignore = [
"E501", # line too long - formatter handles it
"E741", # ambiguous variable name - sometimes makes sense
"UP007", # X | Y unions - Optional[X] is more readable
]
exclude = [".git", ".venv", "__pycache__", "build", "dist"]
[tool.ruff.format]
quote-style = "double"
indent-style = "space"
line-ending = "lf"
# =============================================================================
# TY - Type Checker
# =============================================================================
[tool.ty.environment]
python-version = "3.13"
[tool.ty.src]
include = ["src"]
# =============================================================================
# PYTEST
# =============================================================================
[tool.pytest.ini_options]
testpaths = ["tests"]
python_files = ["test_*.py"]
python_classes = ["Test*"]
python_functions = ["test_*"]
asyncio_mode = "auto"
addopts = [
"--strict-markers",
"--strict-config",
"-ra",
]
Justfile Template
# Check types and lint
check:
uv run ty check
uv run ruff check --fix && uv run ruff format
# Run tests
test *ARGS:
uv run pytest {{ARGS}}
# Run tests with coverage
test-cov:
uv run pytest --cov=src --cov-report=term-missing
# Auto-fix and format
fix:
uv run ruff check --fix
uv run ruff format
# Install/sync all dependencies
install:
uv sync --all-groups
# Update all dependencies
update:
uv lock --upgrade
uv sync --all-groups
# Clean build artifacts
clean:
rm -rf dist/ build/ .pytest_cache/ .ruff_cache/ htmlcov/
find . -type d -name __pycache__ -exec rm -rf {} + 2>/dev/null || true
Pre-commit Config
Create .pre-commit-config.yaml:
repos:
- repo: https://github.com/pre-commit/pre-commit-hooks
rev: v5.0.0
hooks:
- id: check-added-large-files
args: ['--maxkb=1000']
exclude: ^uv\.lock$
- id: detect-private-key
- id: check-merge-conflict
- id: check-yaml
- id: check-toml
- id: end-of-file-fixer
- id: trailing-whitespace
- id: mixed-line-ending
args: ['--fix=lf']
- repo: https://github.com/astral-sh/ruff-pre-commit
rev: v0.8.4
hooks:
- id: ruff
args: [--fix]
- id: ruff-format
exclude: |
(?x)^(
\.venv/.*|
\.git/.*|
__pycache__/.*|
build/.*|
dist/.*|
uv\.lock
)$
Then run: uv run pre-commit install
Project Structure
Always use src layout:
my-project/
src/
my_project/
__init__.py
cli.py
models.py
tests/
conftest.py
test_models.py
pyproject.toml
Justfile
uv.lock
.python-version
.pre-commit-config.yaml
.gitignore
Daily Workflow
just check # Type check + lint + format
just test # Run tests
just test -x # Stop on first failure
just fix # Auto-fix lint issues
uv add httpx # Add a dependency
uv add --dev hypothesis # Add dev dependency
uv run python -m my_project # Run the project
Existing Project Migration
# 1. Install uv if not present
brew install uv
# 2. Convert requirements.txt to pyproject.toml deps
uv add -r requirements.txt
# 3. Replace mypy with ty
uv remove --dev mypy
uv add --dev ty
# 4. Replace black/flake8/isort with ruff
uv remove --dev black flake8 isort
uv add --dev ruff
# 5. Apply pyproject.toml config sections from template above
# 6. Create Justfile from template above
# 7. Run: just check
Reference Docs
Detailed guides for each tool in references/:
- uv-reference.md - Project init, dependencies, lock/sync, Python versions, build/publish
- ty-reference.md - Configuration, rules, CLI flags, known limitations
- ruff-reference.md - Rule sets, formatter options, per-file ignores, CI integration
- pytest-reference.md - Plugins, fixtures, async testing, conftest patterns
- justfile-reference.md - Syntax, variables, parameters, shebang recipes, settings
Resources
Recommended Agent Skills
Expand your agent's capabilities with these related and highly-rated skills.
command-skill-creator
Create automation command skills (slash commands) for Claude Code projects. Use when building `/slash-commands` that automate multi-step workflows - deploys, commits, releases, migrations, cross-repo operations, or any repeatable process. Triggers on "create a command", "make a slash command", "automate this workflow", "turn this into a command", "build a command skill", or when designing phased execution skills with approval gates. For command-type skills (imperative prompts in `.claude/skills/`), NOT knowledge/reference skills.
openclaw-ref
OpenClaw platform reference - plugin system, extensions, configuration, boot/provisioning, channels, models, CLI. Use when working on openclaw codebase, building openclaw plugins/extensions, configuring openclaw instances, provisioning openclaw gateways, designing agent provisioning flows (e.g. agentbox), or debugging openclaw config/plugin/channel issues. Triggers on openclaw, openclaw config, openclaw plugin, openclaw extension, openclaw channel, openclaw gateway, openclaw provisioning, openclaw onboarding, openclaw boot, openclaw skills, BOOT.md, openclaw.plugin.json, openclaw-x402, agentbox provisioning.
vite
Configure and optimize Vite 7 for React projects. Covers build tooling, dev server, plugins, HMR, chunk splitting, Environment API, and Rolldown integration. Use when setting up Vite, configuring builds, optimizing bundles, managing plugins, or troubleshooting dev server. Triggers on vite, vite config, vite plugin, HMR, dev server, build optimization, chunk splitting, rolldown, vite proxy, environment api, rolldown-vite.
biome
Lint and format frontend code with Biome 2.4. Covers type-aware linting, GritQL custom rules, domains, import organizer, and migration from ESLint/Prettier. Use when configuring linting rules, formatting code, writing custom lint rules, or setting up CI checks. Triggers on biome, biome config, biome lint, biome format, biome check, biome ci, gritql, migrate from eslint, migrate from prettier, import sorting, code formatting, lint rules, type-aware linting, noFloatingPromises.
solana-development
Build Solana programs with Anchor framework or native Rust. Use when developing Solana smart contracts, implementing token operations, testing programs, deploying to networks, or working with Solana development. Covers both high-level Anchor framework (recommended) and low-level native Rust for advanced use cases.
gh-cli
GitHub CLI for remote repository analysis, file fetching, codebase comparison, and discovering trending code/repos. Use when analyzing repos without cloning, comparing codebases, or searching for popular GitHub projects.
Didn't find tool you were looking for?