ha-nexus-agent

MCP server for Home Assistant — gives AI assistants full control over your smart home through 227 tools across 24 domains: entities (with bulk control + voice expose), automations & scripts (full CRUD + traces), blueprints, dashboards, helpers, areas, devices registry, calendar, todo lists, history, system management, YAML config files, git-based versioning, real-time WebSocket events, Energy Dashboard preferences, Zones (geofencing), Labels & Categories, fuzzy Search & Discovery, add-on management via Supervisor, HACS integration, integration setup via config_flow, Assist voice pipelines (STT/TTS/wake-word), and Lovelace themes.

Works with Claude Code CLI, Claude Desktop, VS Code, Cursor, Windsurf, OpenAI Codex CLI, Gemini CLI.

Installation — Home Assistant Add-on (recommended)

1. In Home Assistant go to Settings → Add-ons → Add-on Store

2. Click the three-dot menu (⋮) → Repositories

3. Add:

   https://github.com/Fistacho/ha-nexus-agent
   

4. Find Nexus Agent and click Install

5. Click Start

6. Click Open Web UI

The web UI shows your API key and generates ready-to-paste config for every MCP client. No manual token setup — the add-on connects to Home Assistant automatically.

Installation — Standalone (outside HA)

git clone https://github.com/Fistacho/ha-nexus-agent
cd ha-nexus-agent
pip install -r requirements.txt
cp .env.example .env
# Edit .env: set HA_URL and HA_TOKEN
python server.py

Open http://localhost:7123 to get your API key and MCP client configs.

Getting a Home Assistant token

1. In HA go to Profile → Security → Long-Lived Access Tokens
2. Click Create Token, name it nexus
3. Paste as HA_TOKEN in .env

Connecting MCP clients

Open http://your-ha-ip:7123 after starting Nexus. The setup page generates the exact command or config snippet for each client — just copy and paste.

All SSE-based clients connect to:

http://your-ha-ip:7123/mcp?token=YOUR_API_KEY

Claude Code CLI

claude mcp add nexus --transport sse "http://your-ha-ip:7123/mcp?token=YOUR_API_KEY" --scope user

OpenAI Codex CLI

codex mcp add nexus --url "http://your-ha-ip:7123/mcp?token=YOUR_API_KEY"

Gemini CLI

gemini mcp add nexus --url "http://your-ha-ip:7123/mcp?token=YOUR_API_KEY"

VS Code

Create .vscode/mcp.json:

{
  "servers": {
    "nexus": {
      "type": "sse",
      "url": "http://your-ha-ip:7123/mcp?token=YOUR_API_KEY"
    }
  }
}

Cursor

Paste into ~/.cursor/mcp.json:

{
  "mcpServers": {
    "nexus": {
      "url": "http://your-ha-ip:7123/mcp?token=YOUR_API_KEY",
      "type": "sse"
    }
  }
}

Windsurf

Paste into ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "nexus": {
      "url": "http://your-ha-ip:7123/mcp?token=YOUR_API_KEY",
      "type": "sse"
    }
  }
}

Claude Desktop (standalone, subprocess mode)

Paste into %APPDATA%/Claude/claude_desktop_config.json (Win) or ~/Library/Application Support/Claude/claude_desktop_config.json (Mac):

{
  "mcpServers": {
    "nexus": {
      "command": "python",
      "args": ["server.py"],
      "cwd": "/path/to/ha-nexus-agent",
      "env": {
        "HA_URL": "http://homeassistant.local:8123",
        "HA_TOKEN": "your_ha_token_here"
      }
    }
  }
}

Tip: Copy the exact config (with your real paths and key) from the Nexus web UI at http://your-ha-ip:7123.

Features

• 227 MCP tools across 24 categories
• Real-time WebSocket — subscribe to state changes, events and triggers live
• Git versioning — every config change auto-committed with instant rollback
• YAML validation before writing any config file
• Setup web UI — auto-generates ready-to-use MCP config for every client
• HA add-on native — one-click install from Add-on Store, no manual token setup
• API key auth — MCP endpoint protected, token passed via URL query parameter

Tools overview

Git versioning

Nexus keeps a git history of your HA config directory. Before every risky change, use git_safe_write_with_checkpoint — it commits the current state first, then applies the change. Roll back instantly if something breaks.

git_init_config()                                    # run once
git_safe_write_with_checkpoint("automations.yaml", new_content)
git_rollback_file("automations.yaml")                # undo single file
git_rollback_to_commit("abc1234")                    # full rollback
git_log(limit=10)                                    # see history

Environment variables