Connect an AI app

Rally runs an MCP (Model Context Protocol) server, so the AI app you already use can build in Rally Studio with you. Once an app is connected, its AI can create games, read and edit your games, check and playtest scripts, and publish your games when you ask it to. It runs on your own plan with that app: Rally never asks for your Claude, ChatGPT or Grok login. This page shows how to connect an app, what it’s allowed to do, and how to take that access away again.

The server’s address is:

https://rally.place/api/mcp

Any app that supports remote MCP servers over Streamable HTTP can use it. On Rally, you’ll find the address and setup steps for each app in two places:

• Use my AI in Studio’s toolbar, while you have a game open. It also gives you a first message to paste into your AI app, so it starts in the right game.
• Settings > Connect an AI (rally.place/app/settings#ai), with your access tokens and connected apps too.

Both show Waiting for your AI… until your app reaches Rally, then turn green: Connected: and the app’s name.

What a connected app can do

A connected app acts as you, with the permissions you approved:

• Only on games you can edit. It sees the games you own and the ones you collaborate on, and nothing else.
• In your Studio draft. Its changes go into the same draft you edit in Studio. Everyone who has the game open sees them at once, labeled with the app’s name.
• Reversibly. Each change is listed in Studio’s Activity tab, where you can revert it while you work.
• Players get changes when you publish. Edits stay in the draft until a new version is published. When you ask your AI to publish, it checks the game runs with a bot first, then publishes it and gives you its link. Only the game’s owner can publish, and a private game becomes unlisted: anyone with the link can play it, without an account.

Permissions

When you connect an app, you approve what it may do. There are three permissions:

Permission	In MCP	Lets the app
Read games	studio:read	List your games; read their objects, properties and scripts; check scripts for errors; search the docs; run playtests; take screenshots of the Studio viewport.
Edit games	studio:edit	Everything Read games allows, plus create and remix games; create, change and delete objects and scripts; change a game’s name, description and who can see it; and publish games you own when you ask.
Publish games	games:publish	Publish games you own. Apps that connected with only this permission can still publish; the rally CLI needs it to publish web games.

Tools the app isn’t allowed to use don’t appear in its list of tools at all. MCP tools lists every tool and the permission it needs.

Connect your app

Claude

These steps work in Claude on the web (claude.ai) and in the desktop app.

1. Open Customize > Connectors and choose + Add > Add custom connector.

2. Name it Rally, enter https://rally.place/api/mcp as the URL, then choose Continue and Add. The sign-in settings Claude suggests are fine.

3. Sign in to Rally if you aren’t already, check what Claude will be able to do, and choose Allow.

4. In a conversation, turn Rally on under + > Connectors, then ask Claude to list your Rally games.

If you don’t see the option to add a custom connector, your Claude plan or your organization’s settings may not allow it.

ChatGPT

1. In ChatGPT, open Plugins, choose + and then Add custom MCP server. If you don’t see it, turn on Developer mode in ChatGPT’s settings first. Not every ChatGPT plan has it.

2. Name it Rally, enter https://rally.place/api/mcp as the server URL, keep OAuth sign-in, and choose Create as a plugin.

3. Sign in to Rally if you aren’t already, check what ChatGPT will be able to do, and choose Allow.

4. In a conversation, type @, pick Rally, and ask it to list your Rally games.

Grok

1. In Grok (grok.com), open Connectors and choose New Connector > Custom.

2. Enter https://rally.place/api/mcp as the URL.

3. Sign in to Rally if you aren’t already, check what Grok will be able to do, and choose Allow.

4. In a conversation, ask Grok to use Rally to list your games.

Claude Code

1. Add Rally as an MCP server for all your projects:

   claude mcp add --transport http --scope user rally https://rally.place/api/mcp

   Leave out --scope user to add it to the current project only.

2. Sign in. Your browser opens:

   claude mcp login rally

   You can also start Claude Code, run /mcp, select rally and choose Authenticate.

3. Sign in to Rally if you aren’t already, check the list of what Claude Code will be able to do, and choose Allow.

4. Back in Claude Code, try it out: ask “List my Rally games”, or run /mcp__rally__make-a-game.

To skip signing in, use an access token instead:

claude mcp add --transport http --scope user rally https://rally.place/api/mcp --header "Authorization: Bearer rgt_your_token"

Codex

1. Add Rally, then sign in. Your browser opens:

   codex mcp add rally --url https://rally.place/api/mcp
   codex mcp login rally

2. Sign in to Rally if you aren’t already, and choose Allow.

3. In Codex, ask it to list your Rally games.

To use an access token instead, add this to ~/.codex/config.toml:

[mcp_servers.rally]
url = "https://rally.place/api/mcp"
bearer_token_env_var = "RALLY_TOKEN"

Then set RALLY_TOKEN to your token where you run Codex, for example export RALLY_TOKEN=rgt_your_token.

Cursor and VS Code

In Rally’s Use my AI dialog or in Settings > Connect an AI, choose the Cursor or VS Code tab, then Add to Cursor or Add to VS Code. Your editor asks to install Rally; confirm, then sign in to Rally and choose Allow when it asks. In VS Code, use Rally in Copilot Chat’s agent mode; /mcp.rally.make-a-game starts a game.

To use an access token instead, add Rally to Cursor’s ~/.cursor/mcp.json:

{
  "mcpServers": {
    "rally": {
      "url": "https://rally.place/api/mcp",
      "headers": { "Authorization": "Bearer rgt_your_token" }
    }
  }
}

or to VS Code’s .vscode/mcp.json:

{
  "servers": {
    "rally": {
      "type": "http",
      "url": "https://rally.place/api/mcp",
      "headers": { "Authorization": "Bearer rgt_your_token" }
    }
  }
}

Other apps

Add a remote MCP server in your app and give it the address https://rally.place/api/mcp.

• If the app supports signing in with OAuth, it opens Rally’s sign-in page when it first connects. Sign in and choose Allow.

• If it doesn’t, configure it to send an Authorization header with an access token. Many apps use a configuration file in this shape:

  {
    "mcpServers": {
      "rally": {
        "url": "https://rally.place/api/mcp",
        "headers": { "Authorization": "Bearer rgt_your_token" }
      }
    }
  }

  Apps that sign in with OAuth can leave out headers.

Check that it’s connected

Keep Use my AI (in Studio) or Settings > Connect an AI open while you set up your app. It says Waiting for your AI… until your app’s first request reaches Rally, then turns green: Connected: and the app’s name. If it stays waiting after you signed in, ask your AI to list your Rally games: some apps only connect when they first need a tool.

Your first message

In Studio, Use my AI gives you a message to paste into your AI app, such as:

Use the Rally tools to work on my game "Lava Rise" (id 1f0c…): add a lava floor that rises every 30 seconds

It names the game and its id, so the AI starts in the right game. Your AI can also start a new game for you: ask it to “Use the Rally tools to make me a new game: …”. Apps that support MCP prompts also offer make-a-game, add-a-mechanic and polish-and-playtest, which start the AI off the way Rally’s own assistant works. See Prompts.

Sign in and approve

When an app connects with OAuth, Rally takes you through two pages:

1. Sign in. If you aren’t signed in to Rally in that browser, enter your email address and choose Send code, then enter the six-digit code from the email. Codes expire after 10 minutes.

2. Approve. The next page says which app wants to use your Rally account and which account you’re signed in as. Under It will be able to, it lists exactly what the app asked for. It also shows where you’ll be sent back to: check that it’s the app you’re connecting. Choose Allow to connect, or Deny to stop.

You can’t change the list on this page: it’s what the app requested. Rally suggests Read games and Edit games to apps when they connect. With Edit games, the app’s AI can publish the games you own when you ask it to. You can always publish from Studio yourself too.

The list may also include sign-in details such as “Know who you are on Rally” or “See your email address”, and “Stay connected until you disconnect it”. None of those give access to your games. Apps that asked to stay connected renew their access on their own; others ask you to sign in again from time to time.

See and remove connected apps

1. On Rally, open Settings > Connect an AI.

2. Under Connected apps, find the app. Each one shows the permissions it has and when you connected it.

3. Choose Disconnect.

Disconnecting takes effect immediately: the app can’t make another request until you connect it again and approve it. Access tokens are listed separately, under Access tokens, each with a Revoke button. See Developer tokens.

Troubleshooting

“Sign in to Rally to use this server.” The app isn’t signed in, or its sign-in expired. In Claude Code, run /mcp, select rally and choose Authenticate. In other apps, reconnect. If you use an access token, check that the header is Authorization: Bearer followed by the whole token, and that the token hasn’t been revoked.

“This connection isn’t allowed to do that: it needs the … permission.” The app is missing a permission. Disconnect it in Settings > Connect an AI and connect again, or use an access token that has the permission.

The app doesn’t see a game. Apps only see games you own or collaborate on. To work on someone else’s game, ask its owner to add you as a collaborator. See Collaboration.

Publishing doesn’t happen. Only a game’s owner can publish, from a connection that can edit games. Before publishing, Rally compiles the scripts and runs the game for a few seconds with a bot: if a script fails, nothing is published and the AI is told which errors to fix. Studio’s built-in assistant still asks the owner to approve in Studio.

Screenshots fail. The screenshot tool needs the game open in a Studio tab. If the tab is in the background, bring it to the front and ask again.

“Too many requests — slow down.” Each account can make 240 requests a minute. Wait a moment and try again.

The app can’t connect at all. Rally’s server uses the Streamable HTTP transport. Apps that only support the older SSE transport can’t connect to it.

The approval page says the link is incomplete, the app isn’t registered, or the request may have expired. Go back to the app and start connecting again.

Something still doesn’t work. Ask your AI to report it to Rally: it sends Rally’s team what you were trying to do, what went wrong and its last few tool calls, and you can ask it later what became of the report. See Reporting problems.

For developers of MCP clients

If you’re building an app that connects to Rally:

• Transport: Streamable HTTP at https://rally.place/api/mcp. The server is stateless and answers POST requests only; GET returns 405. Responses may stream as server-sent events.
• Authorization: OAuth with the authorization code flow and PKCE (S256). An unauthenticated request gets 401 with a WWW-Authenticate header pointing to the protected resource metadata at https://rally.place/.well-known/oauth-protected-resource/api/mcp. The authorization server is https://rally.place/api/auth, with its metadata at https://rally.place/.well-known/oauth-authorization-server/api/auth.
• Client registration: dynamic client registration and client ID metadata documents are both supported.
• Scopes: studio:read, studio:edit (which includes creating, remixing and publishing your own games) and games:publish. The 401 challenge suggests studio:read studio:edit. Request offline_access to get refresh tokens.
• Prompts and instructions: the server offers MCP prompts to connections that may edit, and short server instructions (under 2,048 characters). The get_guide tool returns the full building guide for apps without prompts.
• Tokens: send them as Authorization: Bearer … headers. Access tokens last an hour. Include the resource indicator https://rally.place/api/mcp when you request tokens, so they’re issued for this server. Sender-constrained (DPoP) tokens aren’t accepted.
• Developer tokens: instead of OAuth, a client can send a Rally access token (rgt_…) in the same header.
• Rate limit: 240 requests per minute per account. Over the limit, the server answers 429 with a Retry-After header.

Next steps

Build a game with AIA complete walkthrough, from the first prompt to a published game.

MCP toolsEvery tool, its arguments and the permission it needs.

Developer tokensAccess tokens for apps that use a header instead of signing in.