python-expert-best-practices-code-review

name	python-expert-best-practices-code-review
description	Python best practices for writing production-grade code. This skill should be used when writing, reviewing, or refactoring Python code. Triggers on tasks involving Python development, error handling patterns, dictionary operations, and code quality improvements.
license	MIT
metadata	{"author":"wispbit","version":"1.0.0"}

Python 3.14+ Expert Best Practices

Simple, pragmatic, opinionated. Only what matters for writing production-grade python code.

When to Apply

Reference these guidelines when:

• Writing Python functions, classes, or modules
• Reviewing Python code for error handling issues
• Refactoring existing Python codebases
• Implementing data validation and API boundaries
• Optimizing error detection and debugging patterns

Rule Categories by Priority

Priority	Category	Impact	Prefix
1	Error Handling	CRITICAL	dict-, operators-
2	Common Bugs	CRITICAL-HIGH	no-mutable-, no-generic-
3	Code Clarity	HIGH-MEDIUM	listcomp-, no-inline-
4	Code Style	LOW	avoid-, unnecessary-

Quick Reference

• dict-required-keys - Use d[key] for required dictionary keys to fail fast with KeyError
• no-mutable-defaults - No mutable defaults in function/method parameters
• operators-return-notimplemented - Return NotImplemented for unsupported operand types and design + vs += intentionally
• no-generic-except - Avoid generic except clauses to prevent hiding unexpected errors
• listcomp-no-side-effects - List comprehensions must produce a value you use (no side-effect listcomps)
• no-inline-imports - Place all import statements at the top of the file
• avoid-explanatory-comments - Avoid unnecessary comments for self-documenting code
• unnecessary-else-blocks - Avoid unnecessary else blocks after return/break/continue statements

How to Use

Read individual rule files for detailed explanations and code examples:

rules/dict-required-keys.md
rules/no-mutable-defaults.md
rules/operators-return-notimplemented.md
rules/no-generic-except.md
rules/listcomp-no-side-effects.md
rules/no-inline-imports.md
rules/avoid-explanatory-comments.md
rules/unnecessary-else-blocks.md

Each rule file contains:

• Brief explanation of why it matters
• When to use and when not to use the pattern
• Implementation requirements
• Incorrect code example with explanation
• Correct code example with explanation
• Additional context and references