# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

LAN Checker is a Python script that monitors network services and devices, publishing status via MQTT to Home Assistant using MQTT Discovery.

## Commands

```bash
# Install dependencies
pip install -r requirements.txt

# Setup config
cp config.yaml.example config.yaml

# Run
python lan_checker.py
```

## Architecture

- `lan_checker.py` - Main script: config loading, MQTT client, check scheduler
- `checkers/` - Modular check implementations
  - `base.py` - `BaseChecker` abstract class and `CheckResult` dataclass
  - `ping.py`, `http.py`, `snmp.py` - Concrete checker implementations
- `config.yaml.example` - Configuration template (copy to `config.yaml`)

## Adding a New Checker

1. Create `checkers/newtype.py` inheriting from `BaseChecker`
2. Implement `check()` method returning `CheckResult`
3. Register in `checkers/__init__.py` CHECKERS dict

## MQTT Topics

- Discovery: `homeassistant/binary_sensor/lan_checker_{id}/config`
- State: `lan_checker/{id}/state` (JSON with state, message, response_time, last_check)