plugins/solid/skills/solid-python/SKILL.md
SOLID principles for Python 3.12+. Files < 100 lines, interfaces separated, modular architecture. Modules MANDATORY. Use when: writing or refactoring Python code, structuring modules/[feature]/ layers, or defining Protocol-based interfaces.
npx skillsauth add fusengine/agents solid-pythonInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
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Before ANY implementation, use TeamCreate to spawn 3 agents:
Before writing ANY new code:
core/services/, core/interfaces/core/| Layer | Location | Max Lines |
|-------|----------|-----------|
| Routes | modules/[feature]/routes/ | 50 |
| Services | modules/[feature]/services/ | 100 |
| Repositories | modules/[feature]/repositories/ | 100 |
| Interfaces | modules/[feature]/interfaces/ | 30 |
| Models | modules/[feature]/models/ | 50 |
| Shared | core/{services,interfaces,models}/ | - |
NEVER use flat src/ structure - always modules/[feature]/
| Rule | Value |
|------|-------|
| File limit | 100 lines (split at 90) |
| Routes | < 50 lines, delegate to services |
| Interfaces | interfaces/ directory ONLY |
| Docstrings | Every public function documented |
| Type hints | MANDATORY on all signatures |
| Protocols | Use typing.Protocol for interfaces |
| Small interfaces | 1-3 methods max |
| Topic | Reference | When to consult | |-------|-----------|-----------------| | SOLID Principles | principles.md | Quick reference for all 5 principles | | Patterns & Structure | patterns.md | Directory layout, testing, typing |
| Anti-Pattern | Fix |
|--------------|-----|
| Files > 100 lines | Split at 90 |
| Interfaces in impl files | Move to interfaces/ directory |
| Fat interfaces (4+ methods) | Split into small Protocols |
| Flat src/ structure | Use modules/[feature]/ |
| Concrete dependencies | Use Protocol + dependency injection |
| Missing type hints | Add type annotations to all signatures |
testing
Copy self-audit and ban-lists — filler verbs/hype adjectives, slop placeholder names, fake-precise numbers, Title Case headlines, humor in error copy ('Oops!'), em-dash crutch, one copy register per page.
development
Logged-in web apps — dashboards, auth flows, settings, onboarding, data tables, command palettes, modals, toasts. Register `product`: density and glance-speed over marketing polish, no hero/CTA-tricks, every data surface covers empty/loading/error explicitly, tables and dataviz follow preattentive-processing rules.
development
Marketing sites, landing pages, campaign pages — register `brand` (design IS the product). Structure comes from the register's POV + a macrostructure pick, never from copying an inspiration site's section flow. Hero discipline, deviated section order, asymmetric grids, and a silhouette lookalike-test gate before ship.
development
Token-strategy core — OKLCH color rules, neutral tinting, accent-commitment levels, type scale, 8pt spacing grid, touch targets, and the canonical output format of design-system.md (the file the harness gates on). This is routing step 1 of design-method/SKILL.md — read it before design-web/design-webapp/design-ios/design-android, before picking or auditing a single color/type/spacing value.