Pricing App Backend - AI Agent Ruleset

Skills Reference: For detailed patterns, use these skills:
pricing-app-backend
- FastAPI + SQLAlchemy + Alembic patterns
pytest
- Testing patterns (fixtures, mocking, markers)

Auto-invoke Skills

When performing these actions, ALWAYS invoke the corresponding skill FIRST:

Action	Skill
Writing Python tests with pytest	`pytest`

CRITICAL RULES - NON-NEGOTIABLE

Type Hints

ALWAYS: Full type hints everywhere:
```
def get_user(user_id: int) -> User:
```
NEVER: Missing return types or parameter types

Exception Handling

ALWAYS: Specific exceptions:
```
except ValueError:
```
,
```
except HTTPException:
```
NEVER: Bare
```
except:
```
blocks

FastAPI Endpoints

ALWAYS: Explicit response models:

@router.get("/users", response_model=List[UserResponse])

ALWAYS: Dependency injection:

current_user: User = Depends(get_current_user)

ALWAYS: Proper HTTP status codes (200, 201, 400, 401, 403, 404, 422, 500)
ALWAYS: Docstrings explaining business logic

Database

ALWAYS: Explicit column types:
```
Column(String(255))
```
not
```
Column(String)
```
ALWAYS: Create Alembic migrations for schema changes
ALWAYS: Name migrations:
```
YYYYMMDD_description.py
```
ALWAYS: Add indexes for foreign keys and frequent queries
NEVER: Alter DB manually

Security

ALWAYS: Hash passwords with bcrypt
ALWAYS: Validate JWT with
```
get_current_user
```
dependency
ALWAYS: Check permissions:
```
tienePermiso(user, "config")
```
NEVER: Store plain text passwords
NEVER: Log sensitive data

TECH STACK

PROJECT STRUCTURE

backend/
├── app/
│   ├── main.py              # FastAPI app
│   ├── routers/             # Route handlers (NEW)
│   ├── models/              # SQLAlchemy models
│   ├── services/            # Business logic
│   ├── core/                # Config, DB, security
│   └── utils/               # Helpers
├── alembic/versions/        # Migrations
└── scripts/                 # Cron jobs

COMMANDS

# Dev
cd backend
source venv/bin/activate
uvicorn app.main:app --reload --port 8000

# Database
alembic revision --autogenerate -m "description"
alembic upgrade head

# Dependencies
pip install -r requirements.txt

QA CHECKLIST

Type hints on all functions
Endpoints have response models
Auth/permissions checked
No bare
```
except:
```
blocks
Migrations created for schema changes
Indexes added for foreign keys
No hardcoded config values
No sensitive data in logs

REFERENCES

FastAPI: https://fastapi.tiangolo.com
SQLAlchemy: https://docs.sqlalchemy.org
Alembic: https://alembic.sqlalchemy.org
Backend skill:
```
../skills/pricing-app-backend/SKILL.md
```

Pricing App Backend - AI Agent Ruleset

Skills Reference: For detailed patterns, use these skills:

```
pricing-app-backend
```
- FastAPI + SQLAlchemy + Alembic patterns
```
pytest
```
- Testing patterns (fixtures, mocking, markers)

When performing these actions, ALWAYS invoke the corresponding skill FIRST:

Action	Skill
Writing Python tests with pytest	`pytest`

CRITICAL RULES - NON-NEGOTIABLE

ALWAYS: Full type hints everywhere:

def get_user(user_id: int) -> User:

NEVER: Missing return types or parameter types

ALWAYS: Specific exceptions:

except ValueError:

except HTTPException:

NEVER: Bare

except:

blocks

ALWAYS: Explicit response models:

@router.get("/users", response_model=List[UserResponse])

ALWAYS: Dependency injection:

current_user: User = Depends(get_current_user)

ALWAYS: Proper HTTP status codes (200, 201, 400, 401, 403, 404, 422, 500)

ALWAYS: Docstrings explaining business logic

ALWAYS: Explicit column types:

Column(String(255))

not

Column(String)

ALWAYS: Create Alembic migrations for schema changes

ALWAYS: Name migrations:

YYYYMMDD_description.py

ALWAYS: Add indexes for foreign keys and frequent queries

NEVER: Alter DB manually

ALWAYS: Hash passwords with bcrypt

ALWAYS: Validate JWT with

get_current_user

dependency

ALWAYS: Check permissions:

tienePermiso(user, "config")

NEVER: Store plain text passwords

NEVER: Log sensitive data

PROJECT STRUCTURE

backend/
├── app/
│   ├── main.py              # FastAPI app
│   ├── routers/             # Route handlers (NEW)
│   ├── models/              # SQLAlchemy models
│   ├── services/            # Business logic
│   ├── core/                # Config, DB, security
│   └── utils/               # Helpers
├── alembic/versions/        # Migrations
└── scripts/                 # Cron jobs

# Dev
cd backend
source venv/bin/activate
uvicorn app.main:app --reload --port 8000

# Database
alembic revision --autogenerate -m "description"
alembic upgrade head

# Dependencies
pip install -r requirements.txt

Pricing App Backend - AI Agent Ruleset

Pricing App Backend - AI Agent Ruleset

Auto-invoke Skills

CRITICAL RULES - NON-NEGOTIABLE

Type Hints

Exception Handling

FastAPI Endpoints

Database

Security

TECH STACK

PROJECT STRUCTURE

COMMANDS

QA CHECKLIST

REFERENCES

Related Skills

Markdown Converter

Nano Banana Pro

1password

Pricing App Backend - AI Agent Ruleset

Auto-invoke Skills

CRITICAL RULES - NON-NEGOTIABLE

Type Hints

Exception Handling

FastAPI Endpoints

Database

Security

TECH STACK

PROJECT STRUCTURE

COMMANDS

QA CHECKLIST

REFERENCES