cuioss/python-core

Python Core Standards

REFERENCE MODE: This skill provides reference material for Python 3.10+ development. Load standards on-demand based on current task. Do not load all sections at once.

Enforcement

Execution mode: Reference library; load standards on-demand for Python development tasks.

Prohibited actions:

• Do not use typing.List, typing.Dict, or other deprecated generic aliases; use built-in generics
• Do not use bare except: or broad except Exception: without re-raising
• Do not use string concatenation for file paths; use pathlib.Path

Constraints:

• All code must target Python 3.10+ and use modern union syntax (X | Y)
• Type hints required on all public function signatures
• Google-style docstrings required on all public functions
• Context managers required for all resource management

When to Use This Skill

Activate when:

• Writing Python production code — type annotations, data structures, class and function design
• Reviewing Python code — checking adherence to PEP 8 and modern Python patterns
• Refactoring Python code — modernizing type hints, improving error handling, adopting pathlib
• Handling resources — file I/O, context managers, pathlib operations
• Writing async code — asyncio patterns, concurrency, rate limiting
• Naming decisions — module, class, function, variable, and constant naming conventions

Available References

File: standards/python-core.md (771 lines)

Load progressively by section based on current task. Never load the entire file at once.

| Section | Load When | |---------|-----------| | Type Annotations | Writing or reviewing type hints, choosing between built-in generics and collections.abc | | Data Structures | Choosing between dataclass, attrs, pydantic, NamedTuple | | Error Handling | Writing try/except blocks, custom exceptions, validation patterns | | Resource Management | File I/O, context managers, custom resource cleanup | | Path Handling | File path operations, pathlib.Path usage, path security | | Security / injection | Validating untrusted input, running subprocesses, deserializing external data, building SQL (subprocess/shlex, pickle/yaml.safe_load, eval/ast.literal_eval, DB-API placeholders) | | Async Programming | asyncio patterns, concurrency with gather(), rate limiting | | Structural Pattern Matching | match statements, destructuring, class patterns, guard clauses | | Modern Features (3.11-3.13) | Exception groups, @override, itertools.batched() | | Functions and Classes | Function design, class composition, mutable defaults | | Naming Conventions | Module/class/function/variable naming styles | | Imports | Import organization, grouping, and rules | | Docstrings | Google-style format for functions, classes, and modules | | Comprehensions and Generators | List/dict comprehensions, generator expressions | | String Handling | F-strings, multi-line strings, string building |

Load Command:

Read standards/python-core.md

Quick Reference

| Topic | Rule | |-------|------| | Type hints | Built-in generics (list[str]), union syntax (X \| None), collections.abc for parameters | | Data structures | dataclass (default), attrs (performance), pydantic (API boundaries) | | Error handling | Specific exceptions only, minimal try scope, chain with from | | Resources | Always context managers; pathlib.Path for all file/path operations | | Security / injection | No shell=True/argv lists; yaml.safe_load not yaml.load; ast.literal_eval not eval; DB-API placeholders not f-strings | | Pattern matching | match/case for structural destructuring; if/elif for simple comparisons | | Async | asyncio.run() entry point, gather() for concurrency, Semaphore for rate limiting | | Naming | lower_with_under (functions/modules), CapWords (classes), CAPS_WITH_UNDER (constants) | | Docstrings | Google style with Args/Returns/Raises sections | | Imports | Three groups (stdlib, third-party, local), sorted alphabetically |

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