Modern Python tooling and best practices using uv, ruff, ty, and pytest. Covers project setup with pyproject.toml (PEP 735), src layout, linting/formatting with ruff, type checking with ty, testing with pytest and coverage, pre-commit with prek, and security (pip-audit, detect-secrets, actionlint). Use when setting up or working on Python projects, replacing pip/virtualenv with uv, replacing flake8/black/mypy with ruff/ty, adding pre-commit or security scanning, or when the user mentions uv, ruff, ty, pytest, or cookiecutter-python patterns.

Produces Mermaid or PlantUML diagram code from user specifications for UML, architecture, and flow diagrams. Use when the user asks for a diagram (sequence, class, activity, use case, component, state, deployment), diagram code, or when generating diagram script for documentation, design, or the generate_uml MCP tool. Supports Kroki-renderable output.