docs: Update CLAUDE.md with health checks and environment variables

- Add Environment Variables table with all configurable options
- Add Health Check section with haproxy_health and haproxy_domain_health examples
- Update MCP Tools count from 17 to 19
- Add new Health Check tools section
- Update server.py description (line count and tool count)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -60,6 +60,20 @@ journalctl -u haproxy-mcp -f    # Logs
 - External: `https://mcp.inouter.com/mcp` (via HAProxy)
 - **Auto-restore:** Servers restored from `servers.json` on startup
 
+### Environment Variables
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `MCP_HOST` | `0.0.0.0` | MCP server bind host |
+| `MCP_PORT` | `8000` | MCP server port |
+| `HAPROXY_HOST` | `localhost` | HAProxy Runtime API host |
+| `HAPROXY_PORT` | `9999` | HAProxy Runtime API port |
+| `HAPROXY_STATE_FILE` | `/opt/haproxy/data/servers.state` | State file path |
+| `HAPROXY_MAP_FILE` | `/opt/haproxy/conf/domains.map` | Map file path |
+| `HAPROXY_SERVERS_FILE` | `/opt/haproxy/conf/servers.json` | Servers config path |
+| `HAPROXY_POOL_COUNT` | `100` | Number of pool backends |
+| `HAPROXY_MAX_SLOTS` | `10` | Max servers per pool |
+| `LOG_LEVEL` | `INFO` | Logging level (DEBUG/INFO/WARNING/ERROR) |
+
 ## Zero-Reload Domain Management
 
 ### How It Works
@@ -182,7 +196,39 @@ curl -X POST https://mcp.inouter.com/mcp \
   -d '{"jsonrpc":"2.0","method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}},"id":0}'
 ```
 
-## MCP Tools (17 total)
+## Health Check
+
+### System Health (`haproxy_health`)
+Returns overall system status:
+```json
+{
+  "status": "healthy",
+  "components": {
+    "mcp": {"status": "ok"},
+    "haproxy": {"status": "ok", "version": "3.3.2", "uptime_sec": 3600},
+    "config_files": {"status": "ok", "files": {"map_file": "ok", "servers_file": "ok"}}
+  }
+}
+```
+
+### Domain Health (`haproxy_domain_health`)
+Returns backend server status for a specific domain:
+```json
+{
+  "domain": "api.example.com",
+  "backend": "pool_3",
+  "status": "healthy",
+  "servers": [
+    {"name": "pool_3_1", "addr": "10.0.0.1:80", "status": "UP", "check_status": "L4OK"}
+  ],
+  "healthy_count": 1,
+  "total_count": 1
+}
+```
+
+**Status values:** `healthy` (all UP), `degraded` (partial UP), `down` (all DOWN), `no_servers`
+
+## MCP Tools (19 total)
 
 ### Domain Management
 | Tool | Description |
@@ -199,7 +245,13 @@ curl -X POST https://mcp.inouter.com/mcp \
 | `haproxy_remove_server` | Remove server from slot, auto-saved |
 | `haproxy_set_server_state` | Set state: ready/drain/maint |
 | `haproxy_set_server_weight` | Set weight (0-256) |
-| `haproxy_get_server_health` | Get UP/DOWN/MAINT status |
+
+### Health Check
+| Tool | Description |
+|------|-------------|
+| `haproxy_health` | System health (MCP, HAProxy, config files) |
+| `haproxy_domain_health` | Domain-specific health with server status |
+| `haproxy_get_server_health` | Get UP/DOWN/MAINT status for all servers |
 
 ### Monitoring
 | Tool | Description |
@@ -270,7 +322,7 @@ echo "set server pool_1/pool_1_1 state ready" | nc localhost 9999
 ```
 /opt/haproxy/
 ├── mcp/                 # MCP server (streamable-http)
-│   └── server.py        # Main MCP server (~1100 lines, 17 tools)
+│   └── server.py        # Main MCP server (~1300 lines, 19 tools)
 ├── conf/
 │   ├── haproxy.cfg      # Main HAProxy config (100 pool backends)
 │   ├── domains.map      # Domain → Pool mapping