Python Developer

This skill serves as the foundational source of truth for high-integrity Python development across all domains. It enforces strict safety rules, deterministic coding standards, test-driven development, and rigorous testing practices.

1. Control & Safety (The Power of 10)

All Python code must strictly follow the Power of 10 safety rules to ensure reliability, predictability, and memory safety:

1. No Recursion: All tree or graph traversals must use iterative stacks.
2. Hard Loop Bounds: Every while loop must be guarded by MAX_ITERATIONS or TIMEOUT_SECONDS.
3. Memory Discipline: Use __slots__ for high-throughput classes to ensure deterministic memory usage.
4. Validation at Boundary: Use TypeGuard at presentation/entry boundaries. Internal layers assume validated data.
5. Pure Functions: Business logic must be I/O-free and deterministic. Push side effects to infrastructure edges.
6. Dependency Injection: Collaborators and external clients must be passed in via constructors, never instantiated internally.
7. No Magic: Forbidden: eval(), exec(), getattr() for sensitive logic, and dynamic runtime imports.
8. Immutable Invariants: State transitions must be provably immutable against malformed input.
9. Fail-Closed: Logic must default to "Access Denied" or "Operation Aborted" upon any ambiguity or exception.
10. Protocol Interfaces: Decouple components using typing.Protocol rather than tight inheritance.