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PopNx MCPMCP servers for people who use AI · explained in plain words

horizOn

by ProjectMakersDEversion 1.9.1i★ –iRuns on your computer
Registry nameio.github.ProjectMakersDE/horizon-mcp

Install

Overview

Description from the maker (original English)

Docs, live API tools and prompts for the horizOn game backend in Godot, Unity and Unreal.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

  • Connection: Runs on your computer
  • Transport: stdio
  • Category: Other
  • You need to fill in: HORIZON_API_KEY, HORIZON_ACCOUNT_API_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

  • Basic checks: 1 of 1 passed
  • Runs on your computer with your user’s permissions (files, network, apps).
  • You fill in yourself: HORIZON_API_KEY, HORIZON_ACCOUNT_API_KEY, HORIZON_BASE_URL

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

  • npmNode.js installed (for the npx command)

Which app do you use?

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "horizon": {
      "command": "npx",
      "args": [
        "-y",
        "horizon-mcp"
      ],
      "env": {
        "HORIZON_API_KEY": "your-value",
        "HORIZON_ACCOUNT_API_KEY": "your-value",
        "HORIZON_BASE_URL": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add horizon --env HORIZON_API_KEY=your-value --env HORIZON_ACCOUNT_API_KEY=your-value --env HORIZON_BASE_URL=your-value -- npx -y horizon-mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "horizon": {
      "command": "npx",
      "args": [
        "-y",
        "horizon-mcp"
      ],
      "env": {
        "HORIZON_API_KEY": "your-value",
        "HORIZON_ACCOUNT_API_KEY": "your-value",
        "HORIZON_BASE_URL": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "horizon": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "horizon-mcp"
      ],
      "env": {
        "HORIZON_API_KEY": "your-value",
        "HORIZON_ACCOUNT_API_KEY": "your-value",
        "HORIZON_BASE_URL": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

  • HORIZON_API_KEY secret env
    horizOn project API key for the live API tools. The documentation works without it.
  • HORIZON_ACCOUNT_API_KEY secret env
    horizOn account key for the dashboard admin tools.
  • HORIZON_BASE_URL env
    API base URL.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

  • ✓ Pass

    Maker matches the repo

    The registry name was verified with the GitHub account ProjectMakersDE, which owns the repo

  • … Not checked yet

    Still maintained

    We have not read this repo from GitHub yet

  • … Not checked yet

    Has a licence

    We have not read this repo from GitHub yet

  • – Not applicable

    Endpoint responds

    This one runs on your computer; there is no internet endpoint

  • – Not applicable

    Sign-in with OAuth

    Runs on your computer and uses local settings instead

  • … Not checked yet

    No hidden instructions in tool descriptions

    Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

  • More stars than 0% of the other 32725 servers in this category
  • Published to the registry more recently than 72% of the other 32725 servers in this category
  • Basic checks equal to or better than 100% of the other 32725 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is horizOn safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: HORIZON_API_KEY, HORIZON_ACCOUNT_API_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (1.9.1) reached the registry 15 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, Signoff

Alternatives

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Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

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Runs on your computer★ 440MITUpdated 14 months ago
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Remote Desktop Commander

by desktop-commander

Remote Desktop Commander: use files, terminal and processes on your own computers from any AI app.

Runs in the cloud★ 211Updated 2 days ago
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Signoff

by ayuanxx-max

Five gates that make an agent's 'done' provable: run them, read the verdict, audit the record.

Runs on your computerUpdated today
Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

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

The server exposes 29 documentation resources, 120 player tools and 4 workflow prompts. An Account Key enables additional scoped admin tools. These counts come from the registered MCP resources, tools and prompts.

Resources

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

URIDescription
horizon://docs/marketplaceAtomic original-item escrow, exact prices, protected Inbox returns and scoped recovery.
horizon://docs/chatDirect/group/project text, metadata-only realtime, incremental snapshots, original receipts and scoped moderation.
horizon://docs/matchesOpaque turn state, exact revisions, immutable reports, bounded deadlines and original ranked-run recovery.
horizon://docs/shared-objectsOpaque bounded world data, current permissions, exact revisions and trusted ordinary game notices.
horizon://docs/itemsUnique inventory, bounded item properties and atomic server-owned purchases
horizon://docs/groupsGuilds, roles, bounded member pages and revision-safe membership actions
horizon://docs/friendsAtomic social relationships, explicit revisions and exact public friend-code lookup
horizon://docs/achievementsVersioned definitions, permanent completion bits and immediate atomic value rewards
horizon://docs/inboxSession inbox, protected rewards, immutable broadcasts, server clock and safe publication retries
horizon://docs/statisticsAtomic session counters, safe integer batches, explicit original IDs and cache/UTC recovery. SDK and admin examples
horizon://docs/player-valuesAtomic balances and offers, stable operation IDs, all three SDKs, safe retries and support corrections
horizon://overviewWhat is horizOn, core concepts (Account vs User), features, tier system, API structure, and SDKs
horizon://docs/authAuthentication methods (Anonymous, Email, Google), endpoints, SDK code examples, and common errors
horizon://docs/leaderboardLeaderboard score submission, top entries, user rank, entries around user, player profile per entry, validated only boards, with SDK examples
horizon://docs/cloud-saveCloud save/load for JSON and binary data, tier size limits, SDK examples
horizon://docs/remote-configServer-side key-value configuration: feature flags, game balance, A/B testing. SDK examples
horizon://docs/localizationServer-side localized strings across 15 languages: per-key translations, single/all fetch, available languages. SDK examples
horizon://docs/newsIn-game news and announcements with language filtering. SDK examples
horizon://docs/gift-codesGift code validation and redemption, cosmetic grants, server-owned value rewards, compact V2 original intents and exact counter strings. SDK examples
horizon://docs/player-profilePlayer avatar, frame and badges from a per-project cosmetics catalog, unlocks via gift code grants, profile in leaderboard entries. SDK examples
horizon://docs/validated-actionsServer-checked runs: single-use run tickets with a server seed, SHA-256 input log hash, server-only rules, validated only leaderboards, server-owned player state, start context, evidence upload, admin evidence review with sus packages and package export, rejection codes. SDK examples
horizon://docs/feedbackBug reports, feature requests, and general feedback submission. SDK examples
horizon://docs/user-logsServer-side event and error tracking. Requires BASIC tier or higher. SDK examples
horizon://docs/crash-reportingCrash report submission, session tracking, fingerprinting, breadcrumbs, and auto-regression detection. SDK examples
horizon://api/referenceComplete API reference for all horizOn App API endpoints with request/response schemas
horizon://quickstart/godotStep-by-step guide to integrate horizOn in Godot with GDScript examples
horizon://quickstart/unityStep-by-step guide to integrate horizOn in Unity with C# examples
horizon://docs/email-sendingTransactional and event-based email delivery to registered users. Templates, scheduling, status tracking, and SMTP integration. SDK examples
horizon://quickstart/unrealStep-by-step guide to integrate horizOn in Unreal Engine 5.5+ with the official horizOn SDK plugin. C++ and Blueprint examples
Player 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_prepare_gift_code, 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.

The four player-value tools also require the same player session. Never generate another operation ID automatically after an uncertain result.

Every tool declares MCP annotations (readOnlyHint, destructiveHint, idempotentHint, openWorldHint), so clients can tell reads from writes. Examples of destructive tools include 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, plus horizon_purchase_player_value_offer and horizon_adjust_player_value (debit or credit exactly once per persisted operation ID). Many 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.

ToolDescription
horizon_test_connectionTest connection to the horizOn API (health check)
horizon_signup_anonymousCreate a new anonymous user account
horizon_signup_emailCreate a new user account with email and password
horizon_signin_emailSign in with email and password
horizon_signin_anonymousSign in with an anonymous token
horizon_check_authCheck whether a user session is still valid
horizon_list_leaderboardsList available leaderboard boards for multi-board calls
horizon_submit_scoreSubmit a score to the leaderboard (403 VALIDATED_SUBMIT_REQUIRED on validated only boards)
horizon_get_leaderboard_topGet the top leaderboard entries with each player's profile, optionally by board key
horizon_get_user_rankGet a user's leaderboard rank, optionally by board key
horizon_get_leaderboard_aroundGet leaderboard entries around a user's position, optionally by board key
horizon_save_cloud_dataSave cloud data for a user, optionally only at an expectedRevision (409 on conflict)
horizon_load_cloud_dataLoad cloud save data for a user, with its revision
horizon_get_remote_configGet a single remote config value by key
horizon_get_all_remote_configsGet all remote config values
horizon_get_localizationGet a single localized string by key, optionally for a specific language
horizon_get_all_localizationsGet all localized strings, optionally for a specific language
horizon_get_localization_languagesList the languages that have localizations for the app
horizon_get_newsGet news articles with optional language filtering
horizon_validate_gift_codeValidate a gift code without redeeming it
horizon_prepare_gift_codeRead-only V2 preparation; persist all seven original intent fields before consume
horizon_redeem_gift_codeExplicit consume/retry of that saved intent; current state on replay, no automatic replacement or V1 translation
horizon_get_profileGet a player's profile (avatar, frame, badges), unlocks and the cosmetics catalog
horizon_set_profileReplace a player's whole profile (avatar, frame, up to 3 badges)
horizon_get_player_valuesRead balances and operation window with the active player session
horizon_get_player_value_offersRead configured offers for the player
horizon_purchase_player_value_offerPurchase atomically with a caller-persisted operation ID
horizon_adjust_player_valueAdjust within explicitly enabled limits with a stable ID and reason
horizon_start_runStart a server-checked run: single-use ticket with a server seed, optionally bound to a board and with a start context (game, content, simulation and replay format versions, content digest, initial state as base64)
horizon_submit_validatedSubmit a run result with the ticket and the SHA-256 input log hash (given, or computed locally from base64 bytes or text), optionally with earned server-owned values; returns sus (accepted but over a soft threshold); rejections name their code
horizon_get_stateRead the player's server-owned values (balance, earned today, daily cap per value key); read only
horizon_upload_evidenceUpload the input log (text or base64, encoded locally) of a run whose submit result asked for evidence; rejections name their code
horizon_get_statisticsReads a player's statistics snapshot and server operation window.
horizon_get_statistics_definitionsReads the project's statistics catalog conditionally by version.
horizon_update_statisticsApplies one explicit atomic session batch with a caller-persisted operation ID.
horizon_get_achievementsReads visible achievement definitions and permanent completion bits.
horizon_unlock_achievementUnlocks one configured manual achievement once for the authenticated player.
horizon_deliver_achievement_rewardsReads compatibility reward status for up to eight original achievement keys.
horizon_get_friendsReads friends, incoming/outgoing requests, blocks and current limits.
horizon_find_playerFinds one public player by exact UUID or canonical H- friend code in this project.
horizon_send_friend_requestSends Friend Request using the reviewed player revision.
horizon_accept_friend_requestAccepts Friend Request using the reviewed player revision.
horizon_decline_friend_requestDeclines Friend Request using the reviewed player revision.
horizon_cancel_friend_requestCancels Friend Request using the reviewed player revision.
horizon_remove_friendRemoves Friend using the reviewed player revision.
horizon_block_playerBlocks Player using the reviewed player revision.
horizon_unblock_playerUnblocks Player using the reviewed player revision.
horizon_get_groupsReads my groups using a matching player session.
horizon_get_groupReads group using a matching player session.
horizon_get_group_membersReads group members using a matching player session.
horizon_get_group_pendingReads group pending requests using a matching player session.
horizon_create_groupCreates a fresh server-identified group and its leader atomically.

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