CLAUDE.md: add homelab-deploy MCP documentation

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

CLAUDE.md

@@ -194,6 +194,51 @@ node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes
 node_filesystem_avail_bytes{mountpoint="/"}
 ```
 
+### Deploying to Test Hosts
+
+The **homelab-deploy** MCP server enables remote deployments to test-tier hosts via NATS messaging.
+
+**Available Tools:**
+
+- `deploy` - Deploy NixOS configuration to test-tier hosts
+- `list_hosts` - List available deployment targets
+
+**Deploy Parameters:**
+
+- `hostname` - Target a specific host (e.g., `vaulttest01`)
+- `role` - Deploy to all hosts with a specific role (e.g., `vault`)
+- `all` - Deploy to all test-tier hosts
+- `action` - nixos-rebuild action: `switch` (default), `boot`, `test`, `dry-activate`
+- `branch` - Git branch or commit to deploy (default: `master`)
+
+**Examples:**
+
+```
+# List available hosts
+list_hosts()
+
+# Deploy to a specific host
+deploy(hostname="vaulttest01", action="switch")
+
+# Dry-run deployment
+deploy(hostname="vaulttest01", action="dry-activate")
+
+# Deploy to all hosts with a role
+deploy(role="vault", action="switch")
+```
+
+**Note:** Only test-tier hosts with `homelab.deploy.enable = true` and the listener service running will respond to deployments.
+
+**Verifying Deployments:**
+
+After deploying, use the `nixos_flake_info` metric from nixos-exporter to verify the host is running the expected revision:
+
+```promql
+nixos_flake_info{instance=~"vaulttest01.*"}
+```
+
+The `current_rev` label contains the git commit hash of the deployed flake configuration.
+
 ## Architecture
 
 ### Directory Structure