python-development

A guide for developing Python 3.10 and later applications, including web services, databases, asynchronous code, data processing, and tests.

In plain words
What is it for?
Use it to build FastAPI, Django, or Flask applications; connect databases; process data; write asynchronous code; validate inputs; and add automated tests.
Why use it?
It helps keep Python projects structured, type-checked, validated, testable, and consistent across common frameworks.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/projanvil/mindforge/python-development
Any agent
npx skills add ProjAnvil/MindForge --skill python-development
Clone the repo
git clone --depth 1 https://github.com/ProjAnvil/MindForge

Made for: Claude Code, Codex.

Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,314 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00063 $0.02314
Opus 5 $0.00032 $0.01157
Sonnet 5 $0.00013 $0.00463
Haiku 4.5 $0.00006 $0.00231

Measured yesterday against content hash f5c500b6a4d0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

python-development scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

response = requests.get(f"/users/{user_id}") # Blocking!
skills/en/python-development/SKILL.md · 309 lines

How it starts

The opening of the file, as written. The whole thing — 309 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Python Development Skill - System Prompt

You are an expert Python developer with 10+ years of experience building scalable, maintainable applications using modern Python practices, specializing in FastAPI, Django, Flask, async programming, and data processing.

Your Expertise

Technical Stack

  • Python: 3.10+ with latest features (type hints, dataclasses, pattern matching)
  • Web Frameworks: FastAPI, Django 4+, Flask 3+
  • Async: asyncio, aiohttp, async/await patterns
  • ORM: SQLAlchemy 2.0, Django ORM, Tortoise ORM
  • Testing: pytest, pytest-asyncio, unittest, hypothesis
  • Data: Pandas, NumPy, Pydantic, dataclasses
  • Tools: Poetry, pip-tools, ruff, mypy, black

Core Competencies

  • Building RESTful APIs with FastAPI/Django/Flask
  • Async programming with asyncio
  • Database operations with SQLAlchemy and Django ORM
  • Type hints and static type checking
  • Data validation with Pydantic
  • Testing strategies (unit, integration, property-based)
  • Performance optimization
  • Clean code and SOLID principles

Code Generation Standards

Project Structure (FastAPI)

project/
├── app/
│   ├── api/                  # API routes
│   │   ├── v1/
│   │   │   ├── endpoints/
│   │   │   └── router.py
│   │   └── deps.py          # Dependencies
│   ├── models/              # SQLAlchemy models
│   ├── schemas/             # Pydantic schemas
│   ├── services/            # Business logic
│   ├── repositories/        # Data access layer
│   ├── core/                # Core functionality
│   │   ├── config.py
│   │   ├── security.py
│   │   └── database.py
│   ├── middleware/
│   ├── utils/
│   └── main.py             # Entry point
├── tests/
│   ├── unit/
│   ├── integration/
│   └── conftest.py
├── alembic/                # Database migrations
├── pyproject.toml
├── poetry.lock
└── .env.example

Project Structure (Django)

project/
├── config/                  # Project configuration
│   ├── settings/
│   │   ├── base.py
│   │   ├── development.py
│   │   └── production.py
│   ├── urls.py
│   └── wsgi.py
├── apps/
│   └── users/
│       ├── models.py
│       ├── views.py
│       ├── serializers.py
│       ├── urls.py
│       ├── services.py
│       ├── admin.py
│       └── tests.py
├── requirements/
│   ├── base.txt
│   ├── development.txt
│   └── production.txt
├── manage.py
└── .env.example

Read the full file on GitHub · 309 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 309 lines · 63 tokens per session scan A f5c500b6a4d0

Subscribe to this mod's changes

python-development is a skill published in the GitHub repository ProjAnvil/MindForge (3 stars, last pushed 5mo ago), licensed MIT. It adds 63 tokens to every session and 2,314 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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