# Python Architecture

Activate when creating new modules, refactoring class hierarchies, introducing design...

- Repository: https://github.com/microsoft/apm (4171 stars)
- Category: Design
- License: MIT
- Last updated: 2026-10-30
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add microsoft/apm --skill python-architecture -g -a claude-code -y`
Codex: `npx skills add microsoft/apm --skill python-architecture -g -a codex -y`
Cursor: `npx skills add microsoft/apm --skill python-architecture -g -a cursor -y`
Gemini CLI: `npx skills add microsoft/apm --skill python-architecture -g -a gemini-cli -y`

## Description

Activate when creating new modules, refactoring class hierarchies, introducing design patterns, or making changes spanning 3+ files in the APM CLI codebase.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Python Architecture Skill

[Python architect persona](../../../.apm/agents/python-architect.agent.md)

## When to activate

- Creating new Python modules or packages under `src/apm_cli/`
- Refactoring class hierarchies or introducing base classes
- Changes that touch 3+ files with shared logic patterns
- Introducing new design patterns (Strategy, Observer, etc.)
- Cross-cutting concerns (logging, auth, error handling)
- Performance-sensitive paths (parallel downloads, large manifests)

## Key rules

- Follow existing patterns (BaseIntegrator, CommandLogger, AuthResolver) before inventing new ones
- Prefer composition over deep inheritance
- Push shared logic into base classes, not duplicated across siblings
- One canonical owner per decision: route through the existing authority (target_catalog, AuthResolver/host_providers, runtime registry, CommandLogger, CompiledOutputWriter, deployment_ledger, install-outcome, neutral hook IR, BaseIntegrator); extend it, never fork it. Full rule: `.apm/instructions/architecture.instructions.md`
- Lock every centralization with a dual guardrail: a regression test plus a static check in `scripts/lint-architecture-boundaries.sh`