# Backend Standards

> Hono/Bun patterns and backend best practices for this project. Use when implementing API endpoints, WebSocket handlers, services, or server-side logic in packages/server.

- Skill: `majiayu000/backend-standards` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds add majiayu000/backend-standards`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/backend-standards/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/majiayu000/backend-standards

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# Backend Standards

## Key Principles

- **Server is the source of truth** - Backend manages all session/worker state
- **Structured logging** - Use Pino with context objects
- **Resource cleanup** - Always clean up PTY processes and connections
- **Type safety** - Define types in shared package, validate at boundaries

## Tech Stack

- Bun, Hono, bun-pty, Pino, Valibot

## Backend Best Practices

- **Resource Cleanup** - PTY processes, WebSocket connections, file handles must be cleaned up
- **Callback Detachment** - Detach callbacks when resources are destroyed (memory leak prevention)
- **WebSocket Message Types** - Define and validate server→client and client→server types explicitly
- **Output Buffering** - Buffer rapid PTY output before WebSocket send to reduce message frequency
- **Structured Logging** - Use Pino with structured data: `logger.info({ sessionId }, 'message')`

## Detailed Documentation

- [backend-standards.md](backend-standards.md) - Directory structure, Hono, logging, services, testing, security, best practices
- [websocket-patterns.md](websocket-patterns.md) - Dual WebSocket architecture, message protocol, broadcasting