python-development

Python Development

Mandatory gates are owned by the Python rule (${HANDBOOK_ROOT}/rules/200-python.mdc). This skill and its references own procedures and examples.

Guiding Principle

Apply features only when they add clarity, correctness, performance, or security. Prefer simple, intentional solutions (DRY, KISS, YAGNI, Fail Fast).

The Zen of Python (import this)

The canonical aphorisms by Tim Peters (PEP 20). When in doubt about which Python idiom to choose, re-read these. Quote verbatim; do not paraphrase in code reviews.

The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

Run python -c "import this" in any Python REPL to see it.

For per-line operative readings (how to apply each in review), see the Zen section in rules/200-python.mdc.

AI Assistant Guidelines

• Avoid Over-Engineering: Don't recommend boto3 client caching, async/await, or concurrency patterns unless explicitly requested or bottlenecks are evident
• Keep It Simple: Prefer stdlib over complex architectures
• Respect Context: Don't transform a 20-line script into a 200-line framework

Do not review Python by asking whether every language feature or library could be inserted. Recommend a comprehension, generator, decorator, dataclass, protocol, cache, concurrency model, framework, or design pattern only when it removes concrete duplication, enforces a requirement, or addresses measured cost. State the problem first and prefer deletion or a direct implementation.