mypy

mypy is a cursor rule for Cursor from sanjeed5/awesome-cursor-rules-mdc. It costs 1,436 tokens per session, scanned A, original, CC0-1.0.

A set of practical rules for using mypy, a tool that checks Python types before the program runs. It covers shared configuration, strict checks, and integration with automated checks.

In plain words
What is it for?
Use it when setting up or maintaining mypy in a Python project, including pyproject.toml configuration, version pinning, pre-commit hooks, and CI checks.
Why use it?
It helps teams find type mistakes earlier and keep type-checking rules consistent across local development and CI/CD, the automated build and test process.

Cursor rule for Cursor

Written for Cursor: a Cursor rule (.mdc).

Good fit Use it when setting up or maintaining mypy in a Python project, including pyproject.toml configuration, version pinning, pre-commit hooks, and CI checks.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/sanjeed5/awesome-cursor-rules-mdc/mypy
About the project

awesome-cursor-rules-mdc is a generator that creates Cursor MDC rule files from structured library information, using semantic search and language models to gather and organize guidance. Developers use it to produce reusable rules for libraries in Cursor, and the catalogue includes 200 of those rules.

sanjeed5/awesome-cursor-rules-mdc · 3,571 stars · on GitHub

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.

Clone the repo
git clone --depth 1 https://github.com/sanjeed5/awesome-cursor-rules-mdc

Made for: Cursor.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for mypy

README.md
[![agentmods](https://agentmods.dev/badge/rules/sanjeed5/awesome-cursor-rules-mdc/mypy.svg)](https://agentmods.dev/rules/sanjeed5/awesome-cursor-rules-mdc/mypy)
Your own site
<a href="https://agentmods.dev/rules/sanjeed5/awesome-cursor-rules-mdc/mypy"><img src="https://agentmods.dev/badge/rules/sanjeed5/awesome-cursor-rules-mdc/mypy.svg" alt="Measured on agentmods" height="20"></a>
Per session 1,436 This file is loaded in full into every session.
When invoked 1,436 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.01436 $0.01436
Opus 5 $0.00718 $0.00718
Sonnet 5 $0.00287 $0.00287
Haiku 4.5 $0.00144 $0.00144

Measured 4d ago against content hash 37599660c1ee, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

mypy 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 4d 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.

rules-mdc/mypy.mdc · 224 lines

How it starts

The opening of the file, as written. The whole thing — 224 lines — stays where its author put it; the contents beside it link to each section on GitHub.

mypy Best Practices

mypy is the definitive static type checker for Python. Adhering to these guidelines ensures your codebase is robust, maintainable, and catches type errors before runtime.

1. Configuration & Integration

Always use a shared pyproject.toml for mypy configuration. This ensures consistency across the team and CI/CD. Pin your mypy version.

1.1. Centralized Configuration

Always configure mypy via pyproject.toml. This is the modern standard.

❌ BAD: mypy.ini or command-line flags only ✅ GOOD: pyproject.toml

# pyproject.toml
[tool.mypy]
python_version = "3.11"
warn_unused_ignores = true
disallow_untyped_defs = true
disallow_incomplete_defs = true
check_untyped_defs = true
no_implicit_optional = true
strict_optional = true
warn_redundant_casts = true
warn_return_any = true
warn_unreachable = true
# Enable strict mode for new code, or specific modules
# strict = true

1.2. CI/CD & Pre-commit Hooks

Integrate mypy into your CI/CD pipeline and as a pre-commit hook. Catch errors early.

# .pre-commit-config.yaml
- repo: https://github.com/pre-commit/pre-commit-hooks
  rev: v4.5.0 # Use the latest stable version
  hooks:
    - id: check-added-large-files
    - id: check-yaml
    - id: end-of-file-fixer
    - id: trailing-whitespace
- repo: https://github.com/pre-commit/mirrors-mypy
  rev: v1.8.0 # Pin to the same version as your pyproject.toml
  hooks:
    - id: mypy
      args: [--no-strict-optional, --ignore-missing-imports] # Override global strict for pre-commit if needed

1.3. Incremental Adoption

For existing codebases, start with a minimal configuration and gradually enable stricter checks. Prioritize annotating widely imported modules.

# pyproject.toml (initial, less strict)
[tool.mypy]
python_version = "3.11"
ignore_missing_imports = true # Temporarily ignore missing stubs
allow_untyped_defs = true     # Allow unannotated functions

Then, enable stricter checks module by module or globally.

Read the full file on GitHub · 224 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. 4d ago First seen · 224 lines · 1,436 tokens per session scan A 37599660c1ee

Subscribe to this mod's changes

mypy is a cursor rule published in the GitHub repository sanjeed5/awesome-cursor-rules-mdc (3,571 stars, last pushed 3mo ago), licensed CC0-1.0. It adds 1,436 tokens to every session, about $0.0072 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 2026-09-03.