HorizOn README

horizOn MCP Server

MCP server for horizOn Backend-as-a-Service

Gives AI coding assistants documentation, live API tools, and workflow prompts for game and app development.

Quick Install

Add to your MCP client configuration (Claude Desktop, Cursor, etc.):

{
  "mcpServers": {
    "horizOn": {
      "command": "npx",
      "args": ["-y", "horizon-mcp"],
      "env": {
        "HORIZON_API_KEY": "your-api-key-here"
      }
    }
  }
}

Features

Resources (18 docs)

Documentation resources are served directly from the MCP server. No API key required.

Tools (34 tools)

Live API tools that call the horizOn backend. Requires a valid API key.

horizon_submit_score, horizon_save_cloud_data, horizon_load_cloud_data, horizon_redeem_gift_code, horizon_get_profile, horizon_set_profile, horizon_start_run, horizon_submit_validated, horizon_get_state and horizon_upload_evidence also need the player's session: sign in first and pass the returned accessToken as sessionToken.

Every tool declares MCP annotations (readOnlyHint, destructiveHint, idempotentHint, openWorldHint), so clients can tell reads from writes. Destructive tools are horizon_save_cloud_data (replaces the save), horizon_set_profile (replaces the whole profile), horizon_submit_validated (consumes the ticket, can spend balances) and horizon_cancel_email. The read tools that return an object also declare an outputSchema and return structuredContent next to the JSON text. Each description names when to use the tool, which sibling to use instead, what it returns and how to recover from its errors.

Prompts (4 prompts)

Workflow prompts that guide AI assistants through common horizOn tasks.

Configuration

Resources (documentation) work without an API key. Only the live API tools require authentication.

Admin Tools (v1.2+)

With an Account Key (creatable in your horizOn Dashboard -> API Keys -> Create -> Account Key), the MCP server exposes additional tools that let Claude manage your dashboard -- projects, remote config, news, email templates, gift codes, users, leaderboards, cloud-save data, crash reports, feedback, user logs, SMTP, and Validated Actions (rules, runs, player values and the evidence review).

How to get your Account Key

1. Log in to your horizOn Dashboard
2. Navigate to API Keys in the sidebar
3. Click Create API Key
4. Select Account Key as the key type
5. Choose whether the key can access the entire account, a single Project API Key, or selected feature groups
6. Click Create -- your key will be shown once. Copy it immediately.
7. Add the key to your MCP configuration (see Setup below)

Setup

Add both keys to your MCP client configuration:

{
  "mcpServers": {
    "horizOn": {
      "command": "npx",
      "args": ["-y", "horizon-mcp"],
      "env": {
        "HORIZON_API_KEY": "your-project-key (for player-facing tools)",
        "HORIZON_ACCOUNT_API_KEY": "your-account-key (for dashboard tools)"
      }
    }
  }
}

Both can be set together or individually. Admin tools only register when the account key is set -- otherwise the server exposes only the original player-facing tools.

Scope

Account Keys inherit your account's tier (FREE/BASIC/PRO/ENTERPRISE) -- they grant no extra privileges. A key can be full-account, limited to a single Project API Key, limited to selected feature groups, or both. Platform-admin-only endpoints (Blog, Banner, System-Config) are automatically unreachable. A handful of ultra-sensitive endpoints (account deletion, credentials change, key management itself, subscription cancel) require a dashboard session and cannot be called via an Account Key.

When a key is project-scoped, the backend enforces that scope on direct HTTP calls too. Account-wide endpoints or ID-only endpoints that cannot prove project context are rejected for project-scoped keys.

Tool Groups

Admin tools carry the same annotations as the player tools: list, get and statistics tools are read only, update and delete tools are marked destructive.

What is horizOn?

horizOn is a multi-tenant Backend-as-a-Service platform built for game and app developers. It provides a managed backend so developers can focus on building their game or app instead of server infrastructure.

Core features:

• Authentication (Anonymous, Email, Google, Apple)
• Leaderboards
• Cloud Save
• Remote Config
• Localization
• News and Announcements
• Gift Codes
• Player Profile (avatar, frame, badges)
• Validated Actions (server-checked runs, validated only leaderboards, server-owned currency)
• User Feedback
• User Logs
• Crash Reporting
• Email Sending

Learn more at horizon.pm. Install this MCP server via npm.

Supported Engines

• Godot 4.5+ -- GDScript SDK
• Unity 6 -- C# SDK
• Unreal Engine 5.5+ -- C++ and Blueprint SDK

Development

# Clone the repository
git clone https://github.com/ProjectMakersDE/horizOn-mcp.git
cd horizOn-mcp

# Install dependencies
npm install

# Start the server (development mode)
npm run dev

# Build for production
npm run build

# Run tests
npm test

License

MIT