Can it help fix 'fat' route handlers?

Absolutely. It follows the principle of 'Skinny Routes, Fat Services,' moving complex business logic out of routes and into dedicated service layers.

Will it help with performance issues?

Yes, it identifies blocking I/O calls (like time.sleep or synchronous database drivers) inside async routes that can freeze the FastAPI event loop.

Does this skill support Pydantic v2?

Yes, it specifically focuses on modern Pydantic v2 patterns, including ConfigDict, Annotated constraints, and new model validator styles.

How does it handle database access?

It promotes the Repository pattern and proper Dependency Injection for database sessions to ensure your data access layer is decoupled and easily testable.

FastAPI Refactor Specialist

Name: FastAPI Refactor Specialist
Author: SnakeO

bySnakeO

0•

API Development

Transforms FastAPI and Python code into maintainable, high-performance APIs following Pydantic v2 and SOLID principles.

The Refactor FastAPI skill is a specialized tool for Claude Code designed to elevate Python web applications to industry-leading standards. It systematically addresses common technical debt such as 'fat' route handlers, blocking I/O in async contexts, and outdated Pydantic v1 patterns. By applying the Service and Repository patterns, the skill decouples business logic from the transport layer, ensuring code is modular, testable, and scalable. It is particularly useful for teams looking to modernize their codebase, improve concurrency performance, or enforce strict type safety and architectural consistency across their API services.

Key Features

01Identifies and resolves blocking synchronous calls within async route handlers.

02Optimizes dependency injection for database sessions, authentication, and service orchestration.

030 GitHub stars

04Migrates Pydantic v1 models to modern v2 patterns including ConfigDict and Annotated constraints.

05Refactors codebases into modular, domain-driven directory structures for better maintainability.

06Implements the 'Skinny Routes, Fat Services' pattern to decouple business logic.

Use Cases

01Migrating legacy FastAPI projects to take advantage of Pydantic v2 performance and features.

02Auditing and fixing event loop blocking issues in high-traffic production APIs.

03Refactoring monolithic route files into a clean Service-Repository architecture.

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add snakeo/claude-debug-and-refactor-skills-plugin refactor-fastapi

For use in Claude.ai and ChatGPT

Download Skill