Python 3

Python rules for Cursor

Typing, packaging and testing rules for modern Python projects managed with uv or pip.

The rule

Save as .cursor/rules/python.mdc. Cursor picks it up on the next request.

.cursor/rules/python.mdc

---
description: Python conventions
globs: **/*.py
alwaysApply: false
---

- Type-hint every function signature. Use built-in generics (list[str], dict[str, int]).
- Use pathlib for paths and f-strings for formatting.
- Raise specific exceptions; never use a bare except.
- Add dependencies with the project's tool (uv add / poetry add), not by editing lockfiles.
- Write tests with pytest next to the code they cover; run them before finishing.
- Format with the configured formatter (ruff format or black) and fix lint warnings you introduce.

How Cursor loads this rule

Read from the frontmatter above, per Cursor's rules documentation.

  • alwaysApply: false with globs: **/*.py: attached automatically when a matching file is in context.
  • Keep the .mdc extension. A plain .md file in .cursor/rules is ignored by the rules system.
  • Prefer to generate your own? Type /create-rule in Agent and describe what you want; Cursor saves the file to .cursor/rules.
  • Team Rules come first, then Project Rules like this one, then User Rules. Earlier sources win when guidance conflicts.

Cursor rules setup guideCursor Team RulesLet Cursor run commands without asking

Using another agent too?

The same instructions work as plain Markdown in AGENTS.md, which Codex, Gemini CLI, GitHub Copilot and most other coding agents read.

AGENTS.md (section)

## Python

- Type-hint every function signature. Use built-in generics (list[str], dict[str, int]).
- Use pathlib for paths and f-strings for formatting.
- Raise specific exceptions; never use a bare except.
- Add dependencies with the project's tool (uv add / poetry add), not by editing lockfiles.
- Write tests with pytest next to the code they cover; run them before finishing.
- Format with the configured formatter (ruff format or black) and fix lint warnings you introduce.

More templates

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Get Cursor rules and settings changes by email

When Cursor changes how rules, run modes or settings work, we update these templates from the docs and send a short note. One email a week at most.

Reviewed Oct 17, 2026. Written by AgentAtlas. Adapt it to your codebase before relying on it.