Dignified Python

---
name: dignified-python
description:
  Production Python coding standards with automatic version detection (3.10-3.13). Use when writing,
  reviewing, or refactoring Python to ensure adherence to modern type syntax, LBYL exception
  handling, pathlib operations, ABC-based interfaces, and production-tested patterns. Not
  Dagster-specific - applies to any Python project.
references:
  - core-standards
  - cli-patterns
  - versions/python-3.10
  - versions/python-3.11
  - versions/python-3.12
  - versions/python-3.13
  - advanced/api-design
  - advanced/exception-handling
  - advanced/interfaces
  - advanced/typing-advanced
---

# Dignified Python Coding Standards Skill

Production-quality Python coding standards for writing clean, maintainable, modern Python code
(versions 3.10-3.13).

## When to Use This Skill

Auto-invoke when users ask about:

- "make this pythonic" / "is this good python"
- "type hints" / "type annotations" / "typing"
- "LBYL vs EAFP" / "exception handling"
- "pathlib vs os.path" / "path operations"
- "CLI patterns" / "click usage"
- "code review" / "improve this code"
- Any Python code quality or standards question

**Note**: This skill is **general Python standards**, not Dagster-specific. Use
`/dagster-best-practices` for Dagster patterns.

## When to Use This Skill vs. Others

| User Need                    | Use This Skill              | Alternative Skill         |
| ---------------------------- | --------------------------- | ------------------------- |
| "make this pythonic"         | ✅ Yes - Python standards   |                           |
| "is this good python"        | ✅ Yes - code quality       |                           |
| "type hints"                 | ✅ Yes - typing guidance    |                           |
| "LBYL vs EAFP"               | ✅ Yes - exception patterns |                           |
| "pathlib vs os.path"         | ✅ Yes - path handling      |                           |
| "best practices for dagster" | ❌ No                       | `/dagster-best-practices` |
| "implement X pipeline"       | ❌ No                       | `/dg` for implementation  |
| "which integration to use"   | ❌ No                       | `/dagster-integrations`   |
| "CLI argument parsing"       | ✅ Yes - CLI patterns       |                           |

## Core Knowledge (ALWAYS Loaded)

@dignified-python-core.md

## Version Detection

**Identify the project's minimum Python version** by checking (in order):

1. `pyproject.toml` - Look for `requires-python` field (e.g., `requires-python = ">=3.12"`)
2. `setup.py` or `setup.cfg` - Look for `python_requires`
3. `.python-version` file - Contains version like `3.12` or `3.12.0`
4. Default to Python 3.12 if no version specifier found

**Once identified, load the appropriate version-specific file:**

- Python 3.10: Load `versions/python-3.10.md`
- Python 3.11: Load `versions/python-3.11.md`
- Python 3.12: Load `versions/python-3.12.md`
- Python 3.13: Load `versions/python-3.13.md`

## Conditional Loading (Load Based on Task Patterns)

Core files above cover 80%+ of Python code patterns. Only load these additional files when you
detect specific patterns:

Pattern detection examples:

- If task mentions "click" or "CLI" -> Load `references/cli-patterns.md`
- If task mentions "subprocess" -> Load subprocess patterns from core-standards

## Reference Documentation Structure

The `references/` directory contains detailed guidance organized by topic:

### Core References

- **`core-standards.md`** - Essential standards (always loaded)
- **`cli-patterns.md`** - Command-line interface patterns (click, argparse)

### Version-Specific References (`references/versions/`)

- **`python-3.10.md`** - Features available in Python 3.10+
- **`python-3.11.md`** - Features available in Python 3.11+
- **`python-3.12.md`** - Features available in Python 3.12+
- **`python-3.13.md`** - Features available in Python 3.13+

### Advanced Topics (`references/advanced/`)

- **`exception-handling.md`** - LBYL patterns, error boundaries
- **`interfaces.md`** - ABC and Protocol patterns
- **`typing-advanced.md`** - Advanced typing patterns
- **`api-design.md`** - API design principles

## When to Read Each Reference Document

### `references/advanced/exception-handling.md`

**Read when**:

- Writing try/except blocks
- Wrapping third-party APIs that may raise
- Seeing or writing `from e` or `from None`
- Unsure if LBYL alternative exists

### `references/advanced/interfaces.md`

**Read when**:

- Creating ABC or Protocol classes
- Writing @abstractmethod decorators
- Designing gateway layer interfaces
- Choosing between ABC and Protocol

### `references/advanced/typing-advanced.md`

**Read when**:

- Using typing.cast()
- Creating Literal type aliases
- Narrowing types in conditional blocks

### `references/module-design.md`

**Read when**:

- Creating new Python modules
- Adding module-level code (beyond simple constants)
- Using @cache decorator at module level
- Seeing Path() or computation at module level
- Considering inline imports

### `references/api-design.md`

**Read when**:

- Adding default parameter values to functions
- Defining functions with 5 or more parameters
- Using ThreadPoolExecutor.submit()
- Reviewing function signatures

### `references/checklists.md`

**Read when**:

- Final review before committing Python code
- Unsure if you've followed all rules
- Need a quick lookup of requirements

## How to Use This Skill

1. **Core knowledge** is loaded automatically (LBYL, pathlib, basic imports, anti-patterns)
2. **Version detection** happens once - identify the minimum Python version and load the appropriate
   version file
3. **Reference documents** are loaded on-demand based on the triggers above
4. **Additional patterns** may require extra loading (CLI patterns, subprocess)
5. **Each file is self-contained** with complete guidance for its domain