What problem does it solve? Python type hints are never enforced by CPython at runtime, and asyncio code fails silently when blocking calls freeze the event loop or un-awaited tasks swallow errors. This Skill provides concrete patterns and anti-patterns so type annotations actually pass strict checkers and concurrent code behaves correctly. ## Core Features & Use Cases - Static Typing Patterns: Covers Protocol vs ABC, TypedDict for JSON payloads, Literal narrowing, generics with TypeVar and PEP 695 syntax, and strict mypy/pyright enforcement in CI. - Asyncio Concurrency Guidance: Explains the event loop, TaskGroup vs gather, offloading blocking work with asyncio.to_thread, and choosing between async, threads, and processes based on the GIL. - Anti-Pattern Detection: Flags common mistakes like using Any to silence checkers, blocking I/O inside coroutines, fire-and-forget tasks, and threads for CPU-bound work. - Use Case: When reviewing a FastAPI service, apply this Skill to annotate endpoint signatures with TypedDict response shapes, replace requests with httpx.AsyncClient in coroutines, and wrap background jobs in a TaskGroup so failures propagate. ## Quick Start Review my Python module for typing and asyncio issues, annotate the public functions, and fix any blocking calls inside coroutines.
