python-conventions-skills / rules
Cursor rule2 starsChanged 6 months agoMITView on GitHub
Modern Python (3.11+) conventions — type discipline, pathlib, async patterns, structlog, ruff + mypy strict.
Where files are headingNew Cursor rule files have more rules about planning and tracking tasks, and fewer about code style.
Of the Cursor rule files we read, the 4,183 first seen in the last six months, against the older ones: the kind of rule that gained most share, and the kind that lost most. About files like this in general, not this one, and an estimate, since a kind is a pattern in the words.
In this repository2 other files it gives its agents.
- CLAUDE.mdCLAUDE.md
- python-conventionsSkill
The file
We split this python-conventions.mdc into the rules it gives an agent
2 rules. About 0 are common, 2 are distinctive, and 0 are very specific to this project.
≈0
Common · estimate
Many files like this have a rule of this kind.
≈2
Distinctive · estimate
This author's own choices. Worth a look.
0
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Distinctive: line 32
Never time.sleep in async code
- Distinctive: line 37
No print() in library code
≈ “Common” is an estimate: at least 1 in 5 of the 6,668 Cursor rule files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
---
description: Modern Python (3.11+) conventions — type discipline, pathlib, async patterns, structlog, ruff + mypy strict.
globs:
- "**/*.py"
- "**/pyproject.toml"
- "**/requirements*.txt"
alwaysApply: false
---
# Python conventions (3.11+)
## Type discipline
- Type hints on every function, attribute, return
- `from __future__ import annotations` at top
- Pydantic v2 for I/O models
- TypedDict for internal dict shapes
- Literal for string-literal enums
## Stdlib preferences
- pathlib.Path over os.path
- dataclasses over manual __init__
- subprocess.run over os.system (with list args, not shell strings)
- f-strings except in logging (lazy formatting)
- match statements for tagged-union dispatch
## Async
- async def end-to-end (httpx, not requests)
- TaskGroup for structured concurrency (3.11+)
- Never time.sleep in async code
## Logging
- structlog or stdlib with structured extras
- No print() in library code
- Lazy formatting: `logger.info("user %s", id)` not f-string
## Tooling
- ruff (lint + format)
- mypy --strict
- pytest with fixtures
- uv over pip
## Banned
- Bare except
- Mutable default arguments
- `from foo import *`
- eval/exec on user input
- Stringly-typed return contracts
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