python

name	Python
description	Execute these commands after EVERY implementation (see AGENT_AUTOMATION module for full workflow).
version	1.0.0
category	languages
author	Rulebook
tags	["languages","language"]
dependencies	[]
conflicts	[]

Python Project Rules

Agent Automation Commands

CRITICAL: Execute these commands after EVERY implementation (see AGENT_AUTOMATION module for full workflow).

# Complete quality check sequence:
ruff format --check .      # Format check
ruff check .               # Linting
mypy .                     # Type checking
pytest                     # All tests (100% pass required)
pytest --cov               # Coverage check (95%+ required)

# Security audit:
pip-audit                  # Vulnerability scan
pip list --outdated        # Check outdated deps

Python Version

CRITICAL: Use Python 3.11+ for modern features and performance.

• Minimum Version: Python 3.11+
• Recommended: Python 3.12+
• Type Hints: Required for all public APIs

Formatting

• Use ruff format (fast, modern) or black (traditional)
• Line length: 100 characters (configurable)
• Consistent formatting across entire project
• Format before committing

Configuration in pyproject.toml:

[tool.ruff]
line-length = 100
target-version = "py311"

[tool.ruff.format]
quote-style = "double"
indent-style = "space"

Linting

• Use ruff check (fast, comprehensive) or ruff + flake8
• Fix all linting errors before committing
• Document any disabled rules with justification

Configuration in pyproject.toml:

[tool.ruff.lint]
select = ["E", "F", "I", "N", "W", "UP", "B", "A", "C4", "SIM"]
ignore = ["E501"]  # Line too long (handled by formatter)

[tool.ruff.lint.per-file-ignores]
"tests/*" = ["S101"]  # Allow assert in tests

Type Checking

• Use mypy for static type checking
• All public APIs must have type hints
• Use typing module for complex types
• Gradual typing allowed for legacy code

Configuration in pyproject.toml:

[tool.mypy]
python_version = "3.11"
strict = true
warn_return_any = true
warn_unused_configs = true
disallow_untyped_defs = true

Example:

from typing import Optional, List, Dict, Any

def process_data(
    input_data: str,
    options: Optional[Dict[str, Any]] = None
) -> List[str]:
    """Process input data and return results."""
    # Implementation
    return []

Testing

• Framework: pytest
• Location: /tests directory
• Coverage: Must meet project threshold (default 95%)
• Fixtures: Use pytest fixtures for setup/teardown
• Parametrize: Use @pytest.mark.parametrize for multiple test cases

Example test structure:

import pytest
from mymodule import process_data

@pytest.fixture
def sample_data():
    """Provide sample data for tests."""
    return "test input"

def test_process_data_valid_input(sample_data):
    """Test process_data with valid input."""
    result = process_data(sample_data)
    assert result == ["expected"]

@pytest.mark.parametrize("input_val,expected", [
    ("hello", ["HELLO"]),
    ("world", ["WORLD"]),
])
def test_process_data_parametrized(input_val, expected):
    """Test multiple input cases."""
    result = process_data(input_val)
    assert result == expected

Test Categories: S2S and Slow Tests

CRITICAL: Tests must be categorized based on execution time and dependencies.

Test Time Limits

• Fast Tests: Must complete in ≤ 10-20 seconds
• Slow Tests: Any test taking > 10-20 seconds must be marked as slow
• S2S Tests: Tests requiring active server/database must be isolated and run on-demand

S2S (Server-to-Server) Tests

Tests that require active servers, databases, or external services must be isolated using pytest markers.

Implementation:

1. Mark S2S tests with pytest markers:

import pytest
import os

# Regular fast test (always runs)
def test_local_computation():
    """Fast test, no external dependencies."""
    result = compute_locally("input")
    assert result == "expected"

# S2S test (only runs with -m s2s)
@pytest.mark.s2s
def test_database_connection():
    """Requires active database server."""
    db = connect_to_database()
    # ... test implementation

@pytest.mark.s2s
def test_api_integration():
    """Requires active API server."""
    client = create_api_client()
    # ... test implementation

2. Configure pytest.ini or pyproject.toml:

# pytest.ini
[pytest]
markers =
    s2s: Server-to-server tests requiring active services
    slow: Slow tests taking > 20 seconds

Or in pyproject.toml:

[tool.pytest.ini_options]
markers = [
    "s2s: Server-to-server tests requiring active services",
    "slow: Slow tests taking > 20 seconds",
]

3. Run tests:

# Regular tests (excludes S2S)
pytest

# Include S2S tests (requires active servers)
pytest -m s2s

# Run all tests including S2S
pytest -m "not slow"  # Fast + S2S, excludes slow

Slow Tests

Tests that take > 10-20 seconds must be marked and run separately.

Implementation:

1. Mark slow tests with pytest markers:

import pytest

# Fast test (always runs)
def test_quick_operation():
    """Completes in < 1 second."""
    result = quick_compute("input")
    assert result == "expected"

# Slow test (only runs with -m slow)
@pytest.mark.slow
def test_heavy_computation():
    """Takes 30+ seconds."""
    # Heavy processing, large dataset, etc.
    result = process_large_dataset()
    assert result is not None

@pytest.mark.slow
def test_large_file_processing():
    """Processes large files, takes > 20 seconds."""
    result = process_file("large_file.dat")
    assert result.success

2. Run tests:

# Regular tests (excludes slow and S2S)
pytest -m "not slow and not s2s"

# Include slow tests
pytest -m slow

# Run all tests
pytest -m ""  # Empty marker means all tests

3. Add pytest configuration for timeouts:

# conftest.py
import pytest

@pytest.fixture(autouse=True)
def configure_timeouts(request):
    """Configure timeouts based on test markers."""
    if 'slow' in request.keywords:
        request.node.add_marker(pytest.mark.timeout(300))  # 5 minutes
    elif 's2s' in request.keywords:
        request.node.add_marker(pytest.mark.timeout(60))  # 1 minute
    else:
        request.node.add_marker(pytest.mark.timeout(20))  # 20 seconds

4. Add scripts in pyproject.toml or setup.py:

[tool.poetry.scripts]
test = "pytest -m 'not slow and not s2s'"
test-s2s = "pytest -m s2s"
test-slow = "pytest -m slow"
test-all = "pytest"

Best Practices

• ✅ Always run fast tests in CI/CD by default
• ✅ Isolate S2S tests - never run them in standard test suite
• ✅ Mark slow tests - prevent CI/CD timeouts
• ✅ Document requirements - specify which servers/services are needed for S2S tests
• ✅ Use timeouts - Set appropriate timeouts: @pytest.mark.timeout(60)
• ✅ Use pytest markers - @pytest.mark.s2s and @pytest.mark.slow
• ✅ Skip conditionally - @pytest.mark.skipif(not os.getenv('RUN_S2S_TESTS'), reason='S2S tests disabled')
• ❌ Never mix fast and slow/S2S tests in same test run
• ❌ Never require external services for standard test suite
• ❌ Never exceed 10-20 seconds for regular tests

Dependency Management

CRITICAL: Use modern dependency management tools.

Recommended: Poetry

[tool.poetry]
name = "myproject"
version = "0.1.0"
description = ""
authors = ["Your Name <[e-mail]>"]

[tool.poetry.dependencies]
python = "^3.11"
requests = "^2.31.0"

[tool.poetry.group.dev.dependencies]
pytest = "^7.4.0"
mypy = "^1.5.0"
ruff = "^0.1.0"

Commands:

poetry install              # Install dependencies
poetry add requests         # Add dependency
poetry add --group dev pytest  # Add dev dependency
poetry update               # Update dependencies

Alternative: pip-tools

# requirements.in
requests>=2.31.0
pydantic>=2.0.0

# requirements-dev.in
-r requirements.in
pytest>=7.4.0
mypy>=1.5.0

Commands:

pip-compile requirements.in
pip-compile requirements-dev.in
pip-sync requirements-dev.txt

Dependency Guidelines

1. Check for latest versions:

   • Use Context7 MCP tool if available
   • Check PyPI: pip index versions <package>
   • Review changelog for breaking changes

2. Version pinning:

   • ✅ Pin exact versions in applications
   • ✅ Use ranges in libraries (>=1.0,<2.0)
   • ✅ Keep dependencies updated regularly
   • ❌ Don't use outdated packages with security issues

Error Handling

• Use specific exception types
• Create custom exceptions when needed
• Document exceptions in docstrings
• Never use bare except:

Example:

class ValidationError(Exception):
    """Raised when data validation fails."""
    
    def __init__(self, message: str, field: str):
        super().__init__(message)
        self.field = field

def validate_data(data: dict[str, Any]) -> None:
    """
    Validate input data.
    
    Args:
        data: The data to validate
        
    Raises:
        ValidationError: If validation fails
    """
    if not isinstance(data, dict):
        raise ValidationError("Data must be a dictionary", "data")

Documentation

• Docstrings: Google or NumPy style
• Type hints: Required for public APIs
• README: Include installation and usage
• API docs: Consider Sphinx for large projects

Example (Google style):

def process_data(input_data: str, options: dict[str, Any] | None = None) -> list[str]:
    """
    Process input data and return results.
    
    Args:
        input_data: The input string to process
        options: Optional processing options
        
    Returns:
        A list of processed strings
        
    Raises:
        ValidationError: If input_data is empty
        
    Examples:
        >>> process_data("hello")
        ['HELLO']
        >>> process_data("world", {"lowercase": True})
        ['world']
    """
    # Implementation
    return []

Project Structure

project/
├── pyproject.toml      # Project metadata and dependencies
├── README.md           # Project overview (allowed in root)
├── CHANGELOG.md        # Version history (allowed in root)
├── AGENTS.md          # AI assistant rules (allowed in root)
├── LICENSE            # Project license (allowed in root)
├── CONTRIBUTING.md    # Contribution guidelines (allowed in root)
├── CODE_OF_CONDUCT.md # Code of conduct (allowed in root)
├── SECURITY.md        # Security policy (allowed in root)
├── src/
│   └── mypackage/
│       ├── __init__.py
│       ├── module.py
│       └── py.typed    # PEP 561 marker for type hints
├── tests/              # Test files
│   ├── __init__.py
│   └── test_module.py
└── docs/               # Documentation

Async Programming

• Use asyncio for async code
• Type hints: async def func() -> Coroutine
• Testing: Use pytest-asyncio

Example:

import asyncio
from typing import List

async def fetch_data(url: str) -> dict[str, Any]:
    """Fetch data asynchronously."""
    # Implementation
    return {}

async def main() -> None:
    """Main async function."""
    results = await asyncio.gather(
        fetch_data("url1"),
        fetch_data("url2"),
    )
    print(results)

if __name__ == "__main__":
    asyncio.run(main())

CI/CD Requirements

Must include GitHub Actions workflows for:

1. Testing (python-test.yml):

   • Test on ubuntu-latest, windows-latest, macos-latest
   • Test on Python 3.11, 3.12
   • Upload coverage reports

2. Linting (python-lint.yml):

   • Format check: ruff format --check .
   • Lint: ruff check .
   • Type check: mypy .

3. Security (python-security.yml):

   • Check for vulnerabilities: pip-audit
   • Scan dependencies: safety check

Package Publication

Publishing to PyPI

Prerequisites:

1. Create account at https://pypi.org
2. Enable 2FA for security
3. Configure trusted publishing (recommended) or create API token
4. For trusted publishing: Add GitHub as publisher in PyPI settings

pyproject.toml Configuration:

[build-system]
requires = ["setuptools>=68.0", "wheel"]
build-backend = "setuptools.build_meta"

[project]
name = "your-package-name"
version = "1.0.0"
description = "A short description of your package"
readme = "README.md"
requires-python = ">=3.11"
license = {text = "MIT"}
authors = [
    {name = "Your Name", email = "[e-mail]"}
]
keywords = ["your", "keywords"]
classifiers = [
    "Development Status :: 4 - Beta",
    "Intended Audience :: Developers",
    "License :: OSI Approved :: MIT License",
    "Programming Language :: Python :: 3",
    "Programming Language :: Python :: 3.11",
    "Programming Language :: Python :: 3.12",
]
dependencies = [
    "requests>=2.31.0",
]

[project.optional-dependencies]
dev = [
    "pytest>=7.4.0",
    "pytest-cov>=4.1.0",
    "ruff>=0.1.0",
    "mypy>=1.7.0",
    "black>=23.12.0",
]

[project.urls]
Homepage = "https://github.com/your-org/your-package"
Documentation = "https://your-package.readthedocs.io"
Repository = "https://github.com/your-org/your-package"
"Bug Tracker" = "https://github.com/your-org/your-package/issues"

[tool.setuptools.packages.find]
where = ["src"]

[tool.setuptools.package-data]
your_package = ["py.typed"]

PEP 625 Package Naming Convention

CRITICAL: Package names must be normalized according to PEP 625.

PyPI requires source distribution filenames to use normalized package names (underscores instead of hyphens).

Naming Rules:

1. Package name in pyproject.toml: Use underscores (_)

   [project]
   name = "my_package_name"  # Correct
   # NOT: name = "my-package-name"  # Will cause deprecation warning
   

2. Package directory: Must match with underscores

   src/
   └── my_package_name/     # Correct
       ├── __init__.py
       └── ...
   

3. Import statement: Uses underscores

   import my_package_name
   from my_package_name import something
   

4. Distribution filename: Will be my_package_name-1.0.0.tar.gz ✅

Common Issue:

If you use hyphens in the package name, PyPI will reject new uploads:

# ❌ WRONG - Will fail PEP 625 compliance
[project]
name = "my-package-name"

# Result: my-package-name-1.0.0.tar.gz (non-compliant)
# PyPI Error: "Filename does not contain normalized project name"

Correct Approach:

# ✅ CORRECT - PEP 625 compliant
[project]
name = "my_package_name"

# Result: my_package_name-1.0.0.tar.gz (compliant)
# PyPI: Accepts upload without warnings

Migration from Hyphenated Names:

If you previously published with hyphens:

1. Update pyproject.toml and setup.py to use underscores
2. Existing uploads remain on PyPI (no action needed)
3. Future uploads will use normalized name
4. PyPI will automatically redirect:
   • pip install my-package-name → works (auto-normalized)
   • pip install my_package_name → works (canonical form)
5. Import statement unchanged: import my_package_name

Reference: PEP 625 - File name of a Source Distribution

Publishing Workflow:

1. Update version in pyproject.toml
2. Update CHANGELOG.md
3. Run quality checks:

   ruff check .
   ruff format --check .
   mypy .
   pytest
   

4. Build package:

   python -m build
   twine check dist/*
   

5. Test on Test PyPI (optional):

   twine upload --repository testpypi dist/*
   

6. Create git tag: git tag v1.0.0 && git push --tags
7. GitHub Actions automatically publishes to PyPI
8. Or manual publish: twine upload dist/*

Publishing Checklist:

• ✅ All tests passing (pytest)
• ✅ Type checking passes (mypy .)
• ✅ Linting passes (ruff check .)
• ✅ Code formatted (ruff format .)
• ✅ Version updated in pyproject.toml
• ✅ CHANGELOG.md updated
• ✅ README.md up to date
• ✅ LICENSE file present
• ✅ Package name uses underscores (PEP 625 compliant)
• ✅ py.typed marker for type hints
• ✅ Package builds successfully (python -m build)
• ✅ Package checks pass (twine check dist/*)
• ✅ Manifest complete (check-manifest)
• ✅ Verify dist filename: my_package-1.0.0.tar.gz (underscores) ✅

Trusted Publishing (Recommended):

PyPI trusted publishing eliminates the need for API tokens:

1. Go to PyPI → Your Account → Publishing

2. Add a new pending publisher:

   • PyPI Project Name: your-package-name
   • Owner: your-github-org
   • Repository: your-repo-name
   • Workflow: python-publish.yml
   • Environment: release (optional)

3. GitHub Actions will authenticate automatically using OIDC

Versioning:

Use semantic versioning and consider:

• Automated versioning: Use tools like bump2version or setuptools_scm
• Version from git tags: Configure setuptools_scm in pyproject.toml:

[build-system]
requires = ["setuptools>=68.0", "setuptools_scm>=8.0"]

[tool.setuptools_scm]
version_file = "src/your_package/_version.py"

Type Hints:

Include py.typed marker for PEP 561 compliance:

touch src/your_package/py.typed

This tells type checkers your package includes type information.