Python Engineering Doctrine (Python ≥ 3.14)

I. Core Doctrine

• Runtime: Python ≥ 3.14 (Nogil-Ready).
• Mindset: Design as if the GIL does not exist (thread-safe by default).

II. Typing & Static Guarantees

• Typing: Mandatory strict typing. Use pyright (preferred) or mypy --strict.
• Type Escape Policy: # type: ignore is forbidden unless justified and documented.

III. Code Style & Structure

• Formatting: ruff as the single source of truth.
• Data Modeling: Prefer immutable models. Use @dataclass(frozen=True).
• Async: Use asyncio.TaskGroup for structured concurrency.

IV. Error Model & Boundaries

• No Silent Failures: Bare except: is forbidden.
• Explicit Handling: Errors must be handled explicitly or re-raised with context.
• Custom Exceptions: Domain errors must use custom exception classes.