Fronius MCP Server

A Model Context Protocol (MCP) server for the Fronius Solar API. This server enables access to Fronius inverter data through the MCP protocol for direct use in Claude Desktop or any other MCP Host Application.

Features

• ✅ Full TypeScript implementation with strong typing

• ✅ Comprehensive Fronius Solar API v1 coverage - all major endpoints

• ✅ Configurable settings via environment variables

• ✅ Both Resources and Tools for maximum flexibility

• ✅ Connection testing on startup and via tools

• ✅ Claude Desktop integration with network permissions guide

Related MCP server: victron-tcp

Supported Fronius API Endpoints

System & Status

• GetAPIVersion.cgi - API Version

• GetLoggerInfo.cgi - System Status

• GetLoggerLEDInfo.cgi - LED Status

• GetActiveDeviceInfo.cgi - Active Devices

Inverter

• GetInverterInfo.cgi - Static inverter information

• GetInverterRealtimeData.cgi - Real-time data (various DataCollections)

Smart Meter & Power Flow

• GetMeterRealtimeData.cgi - Smart meter real-time data

• GetPowerFlowRealtimeData.fcgi - Energy flow visualization

Battery Storage

• GetStorageRealtimeData.cgi - Battery storage system data (state of charge, power, temperature)

Smart Home Integration

• GetOhmPilotRealtimeData.cgi - OhmPilot smart heating element controller data

Extended Features

• GetArchiveData.cgi - Archive data with flexible time ranges

• GetSensorRealtimeData.cgi - Environmental sensors (temperature, irradiance)

• GetStringRealtimeData.cgi - DC string data (voltage, current per string)

Requirements

• Node.js 20+ (tested with Node.js 24)

• npm or yarn

Installation

# Clone repository
git clone https://github.com/huber/fronius-mcp-server.git
cd fronius-mcp-server

# Install dependencies
npm install

# Build TypeScript
npm run build

Configuration

Environment Variables

Copy .env.example to .env and adjust values:

cp .env.example .env

Available configuration options:

• FRONIUS_HOST - Hostname or IP of Fronius device (default: fronius-inverter)

• FRONIUS_PORT - Port (default: 80)

• FRONIUS_PROTOCOL - Protocol: http or https (default: http)

• FRONIUS_TIMEOUT - Request timeout in ms (default: 10000)

• FRONIUS_DEVICE_ID - Default device ID (default: 1)

• FRONIUS_RETRIES - Number of retry attempts (default: 3)

• FRONIUS_RETRY_DELAY - Delay between retries in ms (default: 1000)

• LOG_LEVEL - Log level: error, warn, info, debug (default: info)

Example Configurations

Local Fronius device with hostname:

FRONIUS_HOST=fronius-inverter.local

With IP address:

FRONIUS_HOST=192.168.1.100

HTTPS (newer models):

FRONIUS_HOST=192.168.1.100
FRONIUS_PROTOCOL=https
FRONIUS_PORT=443

Installation Options

Option 1: NPM Package (Easiest)

The simplest way to install and use the Fronius MCP Server is via npm:

Global Installation

1. Install globally:

npm install -g fronius-mcp-server

2. Run directly:

# Basic usage
fronius-mcp-server --host fronius-inverter.local

# Advanced usage with HTTPS
fronius-mcp-server --host 192.168.1.100 --protocol https --port 443

# Test connection
fronius-mcp-server --test-connection --host fronius-inverter.local

Claude Desktop Configuration

Edit your Claude Desktop configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

Basic Configuration:

{
  "mcpServers": {
    "fronius-solar": {
      "command": "fronius-mcp-server",
      "args": ["--host", "fronius-inverter.local"]
    }
  }
}

Advanced Configuration:

{
  "mcpServers": {
    "fronius-solar": {
      "command": "fronius-mcp-server",
      "args": [
        "--host", "192.168.1.100",
        "--protocol", "https",
        "--port", "443",
        "--timeout", "15000"
      ]
    }
  }
}

CLI Options

fronius-mcp-server --help

Options:
  -h, --host <host>           Fronius inverter hostname or IP address
  -p, --port <port>           Fronius inverter port (default: 80)
  --protocol <protocol>       Protocol http|https (default: http)
  -t, --timeout <timeout>     Request timeout in ms (default: 10000)
  -d, --device-id <deviceId>  Default device ID (default: 1)
  -r, --retries <retries>     Number of retry attempts (default: 3)
  --retry-delay <delay>       Delay between retries in ms (default: 1000)
  -l, --log-level <level>     Log level (default: info)
  --test-connection          Test connection and exit
  --stdio                    Use stdio transport (default for MCP)
  --version                  Show version information

Advantages of NPM Installation

• ✅ Zero setup - No Docker or Node.js project setup required

• ✅ Global availability - Use fronius-mcp-server from anywhere

• ✅ Easy updates - npm update -g fronius-mcp-server

• ✅ Built-in CLI - Rich command-line interface with help

• ✅ Cross-platform - Works on Windows, macOS, Linux

Option 2: Pre-built Docker Image

The easiest way to run the Fronius MCP Server is using the pre-built Docker image from Docker Hub:

Setup Steps

1. Pull the Pre-built Image

# No build required - use the pre-built image
docker pull dirkhuber/fronius-mcp-server:latest

Claude Desktop Configuration

Basic Configuration (Hostname):

{
  "mcpServers": {
    "fronius-solar": {
      "command": "docker",
      "args": [
        "run", "--rm", "-i",
        "-e", "FRONIUS_HOST=fronius-inverter.local",
        "dirkhuber/fronius-mcp-server:latest"
      ]
    }
  }
}

Advanced Configuration (IP with HTTPS):

{
  "mcpServers": {
    "fronius-solar": {
      "command": "docker",
      "args": [
        "run", "--rm", "-i",
        "-e", "FRONIUS_HOST=192.168.1.100",
        "-e", "FRONIUS_PROTOCOL=https",
        "-e", "FRONIUS_PORT=443",
        "-e", "FRONIUS_TIMEOUT=15000",
        "dirkhuber/fronius-mcp-server:latest"
      ]
    }
  }
}

That's it! No need to clone the repository or build anything. The pre-built Docker image contains everything needed.

Advantages of Pre-built Image

• ✅ Zero setup - No cloning, building, or Node.js required

• ✅ Always up-to-date - Latest stable version

• ✅ Multi-platform - Supports both AMD64 and ARM64 architectures

• ✅ Automatic updates - Pull new versions with docker pull dirkhuber/fronius-mcp-server:latest

Option 3: Build Docker Image Yourself

If you prefer to build the image yourself or want to modify the code:

Setup Steps

1. Build the Docker Image

# Clone and build the container image
git clone https://github.com/huber/fronius-mcp-server.git
cd fronius-mcp-server
npm run docker:build

2. Configure Claude Desktop

Edit your Claude Desktop configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

Use the locally built image name fronius-mcp-server instead of the Docker Hub image:

Basic Configuration (Hostname):

{
  "mcpServers": {
    "fronius-solar": {
      "command": "docker",
      "args": [
        "run", "--rm", "-i",
        "-e", "FRONIUS_HOST=fronius-inverter.local",
        "fronius-mcp-server"
      ]
    }
  }
}

Advanced Configuration (IP with HTTPS):

{
  "mcpServers": {
    "fronius-solar": {
      "command": "docker",
      "args": [
        "run", "--rm", "-i",
        "-e", "FRONIUS_HOST=192.168.1.100",
        "-e", "FRONIUS_PROTOCOL=https",
        "-e", "FRONIUS_PORT=443",
        "-e", "FRONIUS_TIMEOUT=15000",
        "fronius-mcp-server"
      ]
    }
  }
}

How Docker Integration Works

• Automatic Lifecycle: Claude Desktop starts a fresh container for each session

• Environment Variables: Environment variables are passed directly as -e parameters in the args array

  • Each environment variable needs its own -e parameter

  • Format: "-e", "VARIABLE_NAME=value"

• Auto-Cleanup: --rm flag removes container when session ends

• No Manual Management: No need to manually start/stop containers

Equivalent Docker Command:

# For the basic configuration, Claude Desktop effectively runs:
docker run --rm -i \
  -e FRONIUS_HOST=fronius-inverter.local \
  dirkhuber/fronius-mcp-server:latest

# For the advanced configuration, it would run:
docker run --rm -i \
  -e FRONIUS_HOST=192.168.1.100 \
  -e FRONIUS_PROTOCOL=https \
  -e FRONIUS_PORT=443 \
  -e FRONIUS_TIMEOUT=15000 \
  dirkhuber/fronius-mcp-server:latest

Final Steps (for both options):

1. Edit your Claude Desktop configuration file with one of the configurations above

2. Completely quit Claude Desktop and restart it

3. Begin a new conversation

4. Test with: "How much power is my solar system producing?"

Alternative: Long-Running Container

If you prefer a long-running container approach:

Docker Compose Setup:

# Use docker-compose for easier management
cp .env.docker .env
# IMPORTANT: Edit .env and set FRONIUS_HOST to your device IP/hostname
# Example: FRONIUS_HOST=fronius-inverter.local or FRONIUS_HOST=192.168.1.100
docker-compose up -d

# Test the setup
./scripts/test-container.sh

Claude Desktop config for long-running container:

{
  "mcpServers": {
    "fronius-solar": {
      "command": "docker",
      "args": ["exec", "-i", "fronius-mcp-server", "node", "dist/server.js"],
      "env": {}
    }
  }
}

Note: For long-running containers, the FRONIUS_HOST is configured when starting the container (via docker-compose.yml or docker run), not in the Claude Desktop config. The docker exec command uses the environment from the running container.

Option 4: Local Development

For development or if you want to build from source:

Claude Desktop Setup

1. MCP Server Configuration

Edit the Claude Desktop configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\\Claude\\claude_desktop_config.json

{
  "mcpServers": {
    "fronius-solar": {
      "command": "node",
      "args": ["/absolute/path/to/fronius-mcp-server/dist/server.js"],
      "env": {
        "FRONIUS_HOST": "fronius-inverter.local"
      }
    }
  }
}

Important: Replace /absolute/path/to/fronius-mcp-server with your actual installation path!

Finding the correct paths:

# Find your installation path
pwd

# Find your node path (if Claude Desktop can't find node)
which node

# Example with full node path:
{
  "mcpServers": {
    "fronius-solar": {
      "command": "/usr/local/bin/node",
      "args": ["/Users/yourname/fronius-mcp-server/dist/server.js"],
      "env": {
        "FRONIUS_HOST": "fronius-inverter.local"
      }
    }
  }
}

2. 🔐 Network Permissions (macOS)

Claude Desktop requires access to the local network to communicate with the Fronius inverter.

How to enable permissions:

1. System Settings → Privacy & Security → Network

2. Find Claude in the app list

3. ✅ Enable Network access for Claude Desktop

4. Completely restart Claude Desktop

With macOS Firewall enabled, additionally:

1. System Settings → Network → Firewall → Options

2. Add Claude Desktop to exceptions list or create rule

3. Start and Test

After configuration:

1. ⚠️ Completely quit Claude Desktop and restart

2. Start new conversation

3. Test with: "How much power is my solar system currently producing?"

Development & Testing

Development Mode

npm run dev

Production

npm run build
npm start

Testing & Debugging

# Full connection test
npm run test-connection

# Linting & Type Checking
npm run lint
npm run typecheck

MCP Resources

The server provides these resources:

• fronius://api/version - API Version

• fronius://system/status - System Status

• fronius://system/led - LED Status

• fronius://inverter/info - Inverter Information

• fronius://inverter/realtime - Inverter Real-time Data

• fronius://meter/realtime - Smart Meter Data

• fronius://powerflow/realtime - Power Flow Data

• fronius://sensors/realtime - Sensor Data

• fronius://strings/realtime - String Data

• fronius://storage/realtime - Battery Storage Data

• fronius://ohmpilot/realtime - OhmPilot Data

• fronius://devices/active - Active Devices

MCP Tools

Available tools for interactive queries:

• get_api_version - Get API version

• get_system_status - Get system status

• get_logger_led_info - Get LED status

• get_inverter_info - Get inverter information

• get_inverter_realtime - Get inverter real-time data

• get_meter_realtime - Get smart meter data

• get_powerflow_realtime - Get power flow data

• get_archive_data - Get historical data

• get_sensor_realtime - Get sensor data

• get_string_realtime - Get string data

• get_storage_realtime - Get battery storage data

• get_ohmpilot_realtime - Get OhmPilot data

• get_active_devices - Get active devices

• test_connection - Test connection

Tool Parameter Examples

Query specific inverter:

{
  "name": "get_inverter_realtime",
  "arguments": {
    "deviceId": 1,
    "dataCollection": "CommonInverterData"
  }
}

Get archive data:

{
  "name": "get_archive_data",
  "arguments": {
    "startDate": "2024-01-01",
    "endDate": "2024-01-31",
    "channel": "EnergyReal_WAC_Sum_Produced"
  }
}

Get battery storage data:

{
  "name": "get_storage_realtime",
  "arguments": {
    "deviceId": 0
  }
}

Get OhmPilot heating data:

{
  "name": "get_ohmpilot_realtime",
  "arguments": {
    "deviceId": 0
  }
}

Troubleshooting

Connection Issues

1. Check hostname/IP:

   ping fronius-inverter.local
   # or
   ping 192.168.1.100

2. Test API access:

   curl \"http://fronius-inverter.local/solar_api/GetAPIVersion.cgi\"

3. Fronius Solar API enabled?

   • In Fronius web interface: System → Hardware → Datamanager

   • Solar API must be enabled

4. Claude Desktop Network Permissions (macOS):

   • System Settings → Privacy & Security → Network

   • Allow Claude Desktop network access

5. Firewall/Router:

   • Port 80/443 must be accessible

   • No firewall blocking between Claude Desktop and Fronius

Debugging

Enable debug logging:

LOG_LEVEL=debug npm run dev

Test API endpoints systematically:

FRONIUS_HOST=fronius-inverter.local npm run debug-fronius

Connection test:

FRONIUS_HOST=fronius-inverter.local npm run test-connection

Compatibility

Unsupported Features

• Some older Fronius devices don't support all API endpoints

• Archive data is not available on all models

Architecture

src/
├── types/           # TypeScript definitions
│   ├── fronius.ts   # Fronius API response types
│   └── config.ts    # Configuration types
├── services/        # Business logic
│   ├── fronius-api.ts  # Fronius API client with retry logic
│   └── config.ts    # Configuration service
├── handlers/        # MCP request handlers
│   ├── resources.ts # Resource-based data access
│   └── tools.ts     # Tool-based interactions
└── server.ts        # Main server with lifecycle management

Release Process

This project uses centralized version management - the version in package.json is the single source of truth for all components (MCP server config, User-Agent headers, etc.).

Creating a Release

1. Update Version

# Bump version in package.json (patch/minor/major)
npm version patch  # 1.0.0 -> 1.0.1
npm version minor  # 1.0.1 -> 1.1.0  
npm version major  # 1.1.0 -> 2.0.0

2. Build and Test

# Verify everything builds and tests pass
npm run build
npm run typecheck
npm run lint
npm run test-connection  # If Fronius device available

3. Create Git Tag and Release

# The npm version command automatically creates a git tag
# Push the tag to trigger GitHub Actions release workflow
git push origin main --tags

4. GitHub Actions will automatically:

• ✅ Run full test suite on multiple Node.js versions

• ✅ Build and test Docker image

• ✅ Create GitHub release with changelog

• ✅ Build and push multi-platform Docker images to Docker Hub

• ✅ Create release archives (.tar.gz and .zip)

5. Docker Hub Update Once the GitHub release is published, users can update to the latest version:

docker pull dirkhuber/fronius-mcp-server:latest
# or specific version
docker pull dirkhuber/fronius-mcp-server:v1.0.1

Version Management

The version is centrally managed in package.json and automatically used by:

• MCP Server Config (src/services/config.ts) - Server name and version

• HTTP User-Agent (src/services/fronius-api.ts) - API client identification

• Docker Tags (.github/workflows/ci.yml) - Container versioning

• Release Assets (GitHub Actions) - Archive naming

Versioning Strategy

• Patch (1.0.0 → 1.0.1): Bug fixes, small improvements

• Minor (1.0.0 → 1.1.0): New features, API additions, non-breaking changes

• Major (1.0.0 → 2.0.0): Breaking changes, API changes, major refactoring

Contributing

1. Fork the repository

2. Create a feature branch

3. Commit your changes

4. Push to the branch

5. Create a Pull Request

License

MIT License - see LICENSE file for details.

Support

• GitHub Issues: For bugs and feature requests

• Fronius API Documentation: Official Fronius Solar API

• MCP Protocol: Model Context Protocol Spec