MCP, OAuth, encrypted tokens

Fantasy Sports MCP Server (ESPN, Sleeper, Fantrax)

League Loom is a free MCP server exposing 18 fantasy league data tools for ESPN, Sleeper, and Fantrax over stateless Streamable HTTP, authorized per user with OAuth 2.1, Dynamic Client Registration, and PKCE.

AI Assistant
Claude, ChatGPT & more
League Loom
Connector: https://leagueloom.com/mcp · ESPN · Sleeper · Fantrax
What kinds of questions can I ask League Loom about my leagues?

League Loom exposes live ESPN, Sleeper, and Fantrax data through MCP tools, so you can ask in plain language.

Try: rosters and standings, weekly matchups, available players, start/sit calls, trade evaluations, and a weekly digest of every league at once.

One connector, all your leagues, no copy-pasting screenshots.
Ask about your leagues…

2 minutes

How to connect

1

Add the connector

In Claude, ChatGPT, or any MCP tool, add a custom connector and paste the League Loom URL, then leave Client ID & Secret blank.

2

Pick your team

A quick wizard finds your leagues and lets you pick your team in each. No API keys.

3

Just ask

Ask about your roster, waivers, matchups, and more, in plain language, across every league.

https://leagueloom.com/mcp

Add it as a custom connector, leave Client ID & Secret blank, then follow the quick wizard.

Why League Loom

MCP, OAuth, encrypted tokens

Most fantasy AI integrations are closed, single-provider plugins that skip Fantrax and lock your data behind a proprietary API. League Loom uses the Model Context Protocol, an open standard for connecting AI clients to external tools, so it works the same way in Claude, ChatGPT, or any other MCP client without custom glue code.

Authorization uses OAuth 2.1 with Dynamic Client Registration and PKCE. Each person authorizes their own ESPN, Sleeper, or Fantrax connection, and credentials are sealed into that person's encrypted access token using AES-256-GCM rather than stored in a shared database.

The server is stateless, holding no per-user session between requests. The current fantasy_* tool surface has 18 registered tools that retrieve or analyze rosters, standings, matchups, schedules, transactions, available players, and league settings. No write-action tools are registered.

FAQ

Questions

Which MCP clients work with it?

Any MCP-compatible client, including Claude, ChatGPT, Gemini, and others. Point the client at https://leagueloom.com/mcp and complete the OAuth flow.

How are credentials handled?

Auth runs over OAuth with Dynamic Client Registration and PKCE. Your league credentials are sealed into your own encrypted connection rather than stored on a shared backend.

How is write authorization controlled?

All 18 registered fantasy_* tools retrieve or analyze league data. No write-action tools are registered today. A credential alone never grants permission, and any future write tool must require explicit confirmation.

Does League Loom run locally or as a hosted server?

Both. When hosted, it runs as a stateless Streamable HTTP MCP server at leagueloom.com/mcp, so any MCP client can connect over the network. It also supports the stdio transport for running it locally on your own machine.

What happens to my league credentials between requests?

Nothing is stored server-side. Your credentials are sealed into your own encrypted access token using AES-256-GCM during OAuth. The server holds no per-user database state, so each request carries its own authorization independently.

Can I use League Loom with MCP clients other than Claude and ChatGPT?

Yes. Since it's built on the open MCP standard with OAuth 2.1 and Dynamic Client Registration, it works with any compliant client, including Cursor, Cline, Goose, and Raycast, not just Claude and ChatGPT.

More ways to use AI for fantasy

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Bring League Loom to your AI tool

Free connector, private setup, and 18 current tools that retrieve or analyze your league data. No write-action tools are registered today.

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