debug:fastapi

What problem does it solve?

This skill helps developers systematically debug FastAPI applications by organizing debugging into four phases, making it easier to reproduce, isolate, fix, and prevent regressions for common FastAPI issues such as async/await problems, Pydantic validation errors, DI failures, CORS, and startup circular imports.

Core Features & Use Cases

• Structured debugging process: Reproduce, isolate, fix, and prevent regressions with phase-based workflow.
• FastAPI-centric tools: uvicorn logging, OpenAPI docs, and middleware debugging patterns to diagnose issues quickly.
• Real-world scenarios: handle 422 errors from Pydantic, dependency injection misconfigurations, CORS errors, database session problems, and circular import startups.
• Guided Quick Start: Provides actionable steps and code templates to start debugging rapidly.

Quick Start

Use the skill to troubleshoot a FastAPI app experiencing 422 errors by enabling uvicorn logs, validating OpenAPI, and adding a debug middleware.