102-python-patterns

A collection of recommended patterns for writing Python code, including type hints, asynchronous input and output, formatting, and error handling.

In plain words
What is it for?
Use it when defining Python functions and data models, handling I/O, running independent tasks together, managing resources, and reporting errors.
Why use it?
It reduces inconsistent code and makes Python programs easier to understand, validate, reuse, and maintain.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/obviousworks/vibe-coding-ai-rules/102-python-patterns
Clone the repo
git clone --depth 1 https://github.com/obviousworks/vibe-coding-ai-rules

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 178 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00178
Opus 5 $0.00000 $0.00089
Sonnet 5 $0.00000 $0.00036
Haiku 4.5 $0.00000 $0.00018

Measured yesterday against content hash 250816d73735, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

102-python-patterns scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

ide-specific/cursor/.cursor/rules/102-python-patterns.mdc · 29 lines

What it actually says

Python Patterns

Type Hints

  • Required for all function signatures (params + return type)
  • Use Pydantic models for data validation
  • Use TypeVar and Generic for reusable types

Async

  • Use async/await for all I/O operations
  • Use asyncio.gather() for concurrent operations
  • Never mix sync and async code in hot paths

Style

  • Follow PEP 8 strictly
  • Use structural pattern matching (Python 3.10+) over complex if/else
  • Prefer dataclasses or Pydantic over plain dicts
  • Use pathlib over os.path

Error Handling

  • Use specific exception types (never bare except)
  • Create custom exceptions for domain errors
  • Use contextlib for resource management
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 29 lines · 0 tokens per session scan A 250816d73735

Subscribe to this mod's changes

102-python-patterns is a cursor rule published in the GitHub repository obviousworks/vibe-coding-ai-rules (88 stars, last pushed 2mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 178 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.