python-api-backend

name	python-api-backend
description	Use this skill for Python backend API work, including FastAPI or Flask style endpoints, request and response models, validation, configuration, environment variables, connectors, background jobs, security-sensitive changes, and integration with a Next.js frontend.

Python API Backend

Use this skill for backend work in Python.

Goals

• Make safe backend changes with explicit validation and error handling.
• Preserve existing architecture and conventions.
• Keep API contracts stable when possible.
• Avoid leaking secrets or weakening security.

Rules

• Inspect the current backend structure before adding new modules.
• Reuse existing config, settings, routers, schemas, and helpers.
• Validate inputs explicitly.
• Return predictable response shapes.
• Keep errors actionable but not overly verbose.
• Avoid silent failures.
• Do not hardcode secrets, URLs, tokens, or credentials.
• Prefer environment-based configuration consistent with the repo.
• Preserve backward compatibility unless the request says otherwise.

API design

• Keep endpoint responsibilities narrow.
• Use clear naming for routes and payload fields.
• Separate transport concerns from service logic where the codebase already follows that pattern.
• If pagination, filtering, or sorting exists elsewhere, mirror the same contract style.

Security

• Treat all external data as untrusted.
• Sanitize and validate connector inputs.
• Avoid exposing stack traces to frontend consumers.
• Do not relax auth, CORS, or permission checks without explicit instruction.
• Flag risky changes clearly.

Integration with Next.js

• Keep response payloads easy for frontend consumption.
• Document changed request and response fields briefly.
• Do not duplicate frontend formatting logic in the API unless necessary.

Editing style

• Change the narrowest possible set of files.
• Reuse existing test or example patterns if present.
• Avoid broad refactors while implementing one endpoint or connector.

Output style

For backend changes:

1. State the contract impact.
2. Implement the smallest safe change.
3. Note any env vars or migration implications.
4. Mention verification steps briefly.