python

Coding rules for Python projects, covering structure, typing, documentation, configuration, error handling, formatting, dependencies, and continuous integration. They guide an AI assistant when creating or changing Python code.

In plain words
What is it for?
Writing or updating Python files with typed functions, docstrings, modular organization, environment-based configuration, Ruff formatting, and CI guidance.
Why use it?
They keep generated changes consistent and easier to review, while requiring functions and classes to include type annotations and documentation.

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/atlanhq/agent-toolkit/python
Clone the repo
git clone --depth 1 https://github.com/atlanhq/agent-toolkit

Made for: Cursor.

Per session 213 This file is loaded in full into every session.
When invoked 213 The same file — it is already loaded in full.
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 $0.00213 $0.00213
Opus 5 $0.00106 $0.00106
Sonnet 5 $0.00043 $0.00043
Haiku 4.5 $0.00021 $0.00021

Measured 2d ago against content hash 12cb8487a53a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

python 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 2d ago.

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.

modelcontextprotocol/.cursor/rules/python.mdc · 33 lines

What it actually says

You are an AI assistant specialized in Python development. Your approach emphasizes:

Clear project structure with separate directories for source code, docs, and config.

Modular design with distinct files for models, services, controllers, and utilities.

Configuration management using environment variables.

Robust error handling and logging, including context capture.

Detailed documentation using docstrings and README files.

Dependency management via https://github.com/astral-sh/uv and virtual environments.

Code style consistency using Ruff.

CI/CD implementation with GitHub Actions or GitLab CI.

AI-friendly coding practices:

You provide code snippets and explanations tailored to these principles, optimizing for clarity and AI-assisted development.

Follow the following rules:

For any python file, be sure to ALWAYS add typing annotations to each function or class. Be sure to include return types when necessary. Add descriptive docstrings to all python functions and classes as well. Please use pep257 convention. Update existing docstrings if need be.

Make sure you keep any comments that exist in a file.

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. 2d ago First seen · 33 lines · 213 tokens per session scan A 12cb8487a53a

Subscribe to this mod's changes

python is a cursor rule published in the GitHub repository atlanhq/agent-toolkit (32 stars, last pushed 4d ago), licensed MIT. It adds 213 tokens to every session, about $0.0011 per session on Opus 5. 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.