python-backend-development

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Translated

Generate Python FastAPI code following project design patterns. Use when creating models, schemas, repositories, services, controllers, database migrations, authentication, or tests. Enforces layered architecture, async patterns, OWASP security, and Alembic migration naming conventions (yyyymmdd_HHmm_feature).

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Sourcelct1407/sidcorp-skills

Added on2026-02-11

NPX Install

npx skill4agent add lct1407/sidcorp-skills python-backend-development

SKILL.md Content

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Python Backend Development Standards

Architecture Overview

Router/Controller → Service → Repository → Database
      ↓                ↓            ↓
   Schemas         Business      SQLAlchemy
  (Pydantic)        Logic         Models

Layer Responsibilities

Layer	Location	Purpose
Models	`app/models/`	SQLAlchemy ORM, database schema
Schemas	`app/schemas/`	Pydantic DTOs (request/response)
Repositories	`app/repositories/`	Database CRUD operations
Services	`app/services/`	Business logic orchestration
Controllers	`app/api/v1/`	FastAPI routes, thin handlers
Migrations	`alembic/versions/`	Database migrations

Naming Conventions

Files

All lowercase with underscores:
```
user_profile.py
```
One entity per file
Match filename to class:
```
user.py
```
→
```
class User
```

Classes

Models:
```
User
```
,
```
BlogPost
```
(PascalCase, singular)
Schemas:
```
UserCreate
```
,
```
UserResponse
```
,
```
UserUpdate
```
Repositories:
```
UserRepository
```
Services:
```
UserService
```

Database

Table names: plural snake_case (
```
users
```
,
```
blog_posts
```
)
Column names: snake_case (
```
created_at
```
,
```
user_id
```
)

Alembic Migrations

File Naming Convention

yyyymmdd_HHmm_<feature>.py

Examples:

```
20260117_0930_create_users_table.py
```
```
20260117_1045_add_email_to_users.py
```
```
20260117_1400_create_api_keys_table.py
```

Create Migration Command

bash

# Generate with autogenerate
alembic revision --autogenerate -m "description"

# Then rename the file to follow convention:
# FROM: xxxx_description.py
# TO:   yyyymmdd_HHmm_description.py

Code Standards

Async Everything

All database operations must be async
Use
```
async def
```
for all handlers, services, repositories
Use
```
await
```
for all I/O operations

Dependency Injection

Use FastAPI
```
Depends()
```
for dependencies
Inject database sessions into services
Services inject repositories

Error Handling

Use custom exceptions in
```
app/core/exceptions.py
```
Let FastAPI exception handlers convert to HTTP responses
Never catch and swallow exceptions silently

Security

Argon2id for password hashing
Parameterized queries (SQLAlchemy ORM)
Input validation (Pydantic)
Rate limiting on auth endpoints

Reference Navigation

Core Patterns:

python-models.md - SQLAlchemy ORM (User, ApiKey)
python-schemas.md - Pydantic v2 patterns
python-repositories.md - Repository pattern
python-services.md - Service layer patterns
python-api-design.md - FastAPI routes and controllers
python-migrations.md - Alembic migration patterns
python-utils.md - Utility functions (datetime, string, validation)

Security & Auth:

python-authentication.md - JWT, API Keys, OAuth
python-middleware.md - Dual auth, rate limiting, credits
python-security.md - OWASP Top 10, input validation

Quality & Operations:

python-testing.md - pytest patterns, fixtures
python-performance.md - Caching, query optimization, async
python-debugging.md - Logging, profiling, error tracking
python-devops.md - Docker, CI/CD, deployment