pyright

A set of rules for using Pyright or BasedPyright, tools that check Python code for type and other programming errors.

In plain words
What is it for?
It is for improving Python code structure, typing, testing, security, performance, and tool configuration.
Why use it?
It gives developers guidance on organizing Python projects, avoiding common mistakes, and applying consistent checking practices.

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/cycloidio/cycloid-mcp-server/pyright
Clone the repo
git clone --depth 1 https://github.com/cycloidio/cycloid-mcp-server

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 3,985 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 $0.03985
Opus 5 $0.00000 $0.01992
Sonnet 5 $0.00000 $0.00797
Haiku 4.5 $0.00000 $0.00398

Measured yesterday against content hash a79215c8e8d7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

pyright 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.

.cursor/rules/pyright.mdc · 292 lines

How it starts

The opening of the file, as written. The whole thing — 292 lines — stays where its author put it; the contents beside it link to each section on GitHub.

pyright and BasedPyright Best Practices: A Comprehensive Guide

This guide provides comprehensive best practices for using pyright and BasedPyright in Python projects. These practices cover code organization, design patterns, performance optimization, security considerations, testing strategies, common pitfalls, and recommended tooling.

1. Code Organization and Structure

1.1 Directory Structure Best Practices

  • Flat vs. Nested: Choose a directory structure that balances simplicity and maintainability. For small projects, a flat structure might suffice. For larger projects, a nested structure that mirrors the module hierarchy is often better. For example:

    my_project/ ├── src/ │ ├── my_module/ │ │ ├── init.py │ │ ├── file1.py │ │ ├── file2.py │ ├── main.py ├── tests/ │ ├── my_module/ │ │ ├── test_file1.py │ │ ├── test_file2.py │ ├── conftest.py ├── pyrightconfig.json ├── pyproject.toml (or setup.py/setup.cfg) ├── README.md

  • src Layout: Use the src layout to separate application code from project metadata. This helps prevent accidental imports of test or configuration files.

1.2 File Naming Conventions

  • Python Naming: Follow standard Python naming conventions (PEP 8):
    • Modules: lowercase_with_underscores.py
    • Classes: PascalCase
    • Functions and variables: lowercase_with_underscores
    • Constants: UPPERCASE_WITH_UNDERSCORES
  • Test Files: Name test files consistently, e.g., test_<module_name>.py or <module_name>_test.py.

1.3 Module Organization

  • Cohesion: Group related functions and classes within a single module.
  • Coupling: Minimize dependencies between modules to improve maintainability.
  • __init__.py: Use __init__.py files to define packages and control namespace imports. Consider explicit relative imports within packages (e.g., from . import module instead of import module).

Read the full file on GitHub · 292 lines

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 · 292 lines · 3,985 tokens per session scan A a79215c8e8d7

Subscribe to this mod's changes

pyright is a cursor rule published in the GitHub repository cycloidio/cycloid-mcp-server (0 stars, last pushed 2mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 3,985 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 2026-08-31.