---
name: universal-anti-patterns
description: "Instructions for universal anti patterns."
---
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## priority: critical
# Universal Anti-Patterns
**Never use:**
- Any type (Python, TypeScript) - use Unknown/generics
- Class-based tests (Python) - function-based only
- Mocking internal services (any language) - use real objects
- Manual dependency management - use lock files
- Blocking I/O in async code (Python/TypeScript) - fully async paths
- Bare exception handlers - catch specific types only
- Magic numbers - extract to named constants
- Inheritance for code reuse - prefer composition
- Global state - dependency injection
- f-strings in logging - structured key=value logging
- Unwrap/panic in production code (Rust) - use Result\<T, E>
- Duplication across bindings - core logic ALWAYS in Rust
