Entry point: /faion-net — invoke this skill for automatic routing to the appropriate domain.

Python Developer Skill

Python development specializing in Django, FastAPI, async programming, and modern Python patterns.

Purpose

Handles all Python backend development including Django full-stack apps, FastAPI async APIs, pytest testing, and Python best practices.

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Context Discovery

Auto-Investigation

Gather Python project context before asking questions:

Signal	How to Check	What It Tells Us
manage.py	Glob("**/manage.py")	Django project
pyproject.toml	Read("pyproject.toml")	Dependencies, Python version, tools
requirements.txt	Read("requirements.txt")	Dependencies (legacy setup)
settings/*.py	Glob("**/settings/*.py")	Django settings structure
services/*.py	Glob("**/services/*.py")	Service layer exists → follow pattern
conftest.py	Glob("**/conftest.py")	pytest fixtures exist → check style
factories.py	Glob("**/factories.py")	Factory Boy used for tests
tasks.py or celery.py	Glob("**/tasks.py")	Celery async tasks used
.pre-commit-config.yaml	Glob("**/.pre-commit-config.yaml")	Pre-commit hooks, linting tools
mypy.ini or pyproject.toml [tool.mypy]	Check for mypy config	Type checking enforced

Read existing code to understand patterns:

- Read a model file to see BaseModel pattern
- Read a service file to see service layer style
- Read a test file to see testing conventions
- Read serializers to see DRF patterns

Discovery Questions

Use AskUserQuestion for Python-specific decisions not clear from investigation.

Q1: Framework Choice (only if not detected)

question: "Which Python framework are you using?"
header: "Framework"
multiSelect: false
options:
  - label: "Django"
    description: "Full-featured web framework with ORM"
  - label: "FastAPI"
    description: "Modern async API framework"
  - label: "Flask"
    description: "Lightweight microframework"
  - label: "No framework (scripts/CLI)"
    description: "Pure Python application"

Routing:

• "Django" → django-* methodologies
• "FastAPI" → python-fastapi, python-async
• "Flask" → python-web-frameworks
• "No framework" → python-basics, python-code-quality

Q2: Code Placement (for new code in Django)

question: "What type of code are you writing?"
header: "Code Type"
multiSelect: false
options:
  - label: "Database operations (create/update/delete)"
    description: "Code that modifies data"
  - label: "Business logic (calculations, transformations)"
    description: "Pure functions, no side effects"
  - label: "API endpoint"
    description: "HTTP request handling"
  - label: "Background task"
    description: "Async/scheduled processing"
  - label: "Not sure"
    description: "I'll help you decide based on what it does"

Routing (Django decision tree):

• "Database operations" → services/ directory
• "Business logic" → utils/ directory (pure functions)
• "API endpoint" → views/ or viewsets/
• "Background task" → tasks/ with Celery
• "Not sure" → Ask what the code does, apply decision tree

Q3: Async Requirements

question: "Does this need async/concurrent execution?"
header: "Async"
multiSelect: false
options:
  - label: "Yes, I/O bound (API calls, file ops)"
    description: "Multiple external calls that can run in parallel"
  - label: "Yes, background processing"
    description: "Long-running tasks that shouldn't block"
  - label: "No, synchronous is fine"
    description: "Simple request-response flow"
  - label: "Not sure"
    description: "I'll analyze and recommend"

Routing:

• "I/O bound" → python-async, asyncio patterns
• "Background processing" → django-celery or FastAPI BackgroundTasks
• "Synchronous" → Standard patterns
• "Not sure" → Analyze task characteristics

Q4: Type Safety Level

question: "What level of type safety do you want?"
header: "Types"
multiSelect: false
options:
  - label: "Strict (full type hints, mypy strict)"
    description: "Maximum type safety, catch errors early"
  - label: "Gradual (key interfaces typed)"
    description: "Type public APIs, internal can be looser"
  - label: "Minimal (match existing code)"
    description: "Follow project's current style"

Routing:

• "Strict" → python-type-hints strict mode, Protocol, TypedDict
• "Gradual" → Type annotations on public functions
• "Minimal" → Match existing codebase style

Q5: Testing Approach (for new features)

question: "How should we approach testing?"
header: "Testing"
multiSelect: false
options:
  - label: "TDD (tests first)"
    description: "Write tests before implementation"
  - label: "Tests after implementation"
    description: "Write tests once code works"
  - label: "Match existing test coverage"
    description: "Follow project's testing patterns"
  - label: "No tests needed"
    description: "Spike/prototype, tests later"

Routing:

• "TDD" → tdd-workflow, write test first
• "Tests after" → django-pytest or python-testing-pytest
• "Match existing" → Read conftest.py, follow patterns
• "No tests" → Skip testing methodologies

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When to Use

• Django projects (models, services, API, testing)
• FastAPI async APIs
• Python async patterns and concurrency
• Python type hints and strict typing
• Python testing with pytest
• Python code quality and tooling

Methodologies

Category	Methodology	File
Django Core
Django standards	Django coding standards, project structure	django-coding-standards.md
Django models	Model design, base model patterns	django-base-model.md
Django models reference	Model fields, managers, migrations	django-models.md
Django services	Service layer architecture	django-services.md
Django API	DRF patterns, serializers, viewsets	django-api.md
Django testing	Django test patterns, factories	django-testing.md
Django pytest	pytest-django, fixtures, parametrize	django-pytest.md
Django celery	Async tasks, queues, beat	django-celery.md
Django quality	Code quality, linting, formatting	django-quality.md
Django imports	Import organization, circular imports	django-imports.md
Django decision tree	Framework selection, when to use Django	django-decision-tree.md
Django decomposition	Breaking down Django monoliths	decomposition-django.md
FastAPI
FastAPI basics	Routes, dependencies, validation	python-fastapi.md
Web frameworks	Django vs FastAPI vs Flask comparison	python-web-frameworks.md
Async Python
Async basics	asyncio, await, event loop	python-async.md
Async patterns	Concurrent patterns, asyncio best practices	python-async-patterns.md
Type Safety
Type hints	Gradual typing, annotations	python-type-hints.md
Python typing	TypedDict, Protocol, Generic	python-typing.md
Testing
pytest basics	Fixtures, parametrize, markers	python-testing-pytest.md
Python Core
Python basics	Language fundamentals, patterns	python-basics.md
Python overview	Quick reference	python.md
Python modern 2026	Python 3.12/3.13 features	python-modern-2026.md
Python code quality	ruff, mypy, black, isort	python-code-quality.md
Poetry setup	Dependency management, pyproject.toml	python-poetry-setup.md

Tools

• Frameworks: Django 5.x, FastAPI 0.1x, Flask
• Testing: pytest, pytest-django, pytest-asyncio, factory-boy
• Type checking: mypy, pyright
• Linting: ruff, flake8, pylint
• Formatting: black, isort
• Package management: poetry, pip-tools, uv

Related Sub-Skills

Sub-skill	Relationship
faion-backend-developer	Database patterns (PostgreSQL, Redis)
faion-api-developer	REST/GraphQL API design
faion-testing-developer	Advanced testing patterns
faion-devtools-developer	Architecture patterns, code quality

Integration

Invoked by parent skill faion-software-developer when working with Python code.

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faion-python-developer v1.0 | 24 methodologies