AI assistant setup

Use GridIron Data NFL fantasy data in Gemini (MCP setup)

Quick answer: Install the GridIron Data extension for Gemini CLI with gemini extensions install https://github.com/avansledright/gridiron-data-mcp, start gemini, and run /mcp auth gridiron-data to sign in with your GridIron Data account in the browser. The extension points Gemini at the hosted server, https://api.gridirondata.com/mcp, and tells it how GridIron player IDs and scoring work. Then ask for NFL projections, stats, news or prop probabilities.

Written by , founder of 45Squared, which builds and runs GridIron Data · Published

Server URL
https://api.gridirondata.com/mcp
Install
Gemini CLI extension
Sign-in
OAuth or API key header
Time
About 2 minutes

What do I need first?

  • Gemini CLI installed.
  • A browser on the same machine for the sign-in (Gemini CLI's OAuth sends you back to localhost). On a server over SSH or in a container, use the API key option below.
  • A GridIron Data account, or your API key from the dashboard. No account? Sign up free (no credit card).

How do I add GridIron Data to Gemini CLI?

  1. Install the extension. In a terminal (not inside an interactive Gemini session), run: 
    gemini extensions install https://github.com/avansledright/gridiron-data-mcp

    The extension is a public GitHub repo with a gemini-extension.json that registers the hosted server as gridiron-data, plus a short GEMINI.md that tells Gemini the player ID format ("First Last#POS") and scoring options.

  2. Sign in. Start gemini and run /mcp auth gridiron-data. A browser opens on a GridIron Data page: sign in and click Allow. Gemini CLI registers itself, so there's no client ID to enter.
  3. Check it. Run /mcp inside Gemini CLI: gridiron-data is listed with its tools.

Can I add it without the extension?

Yes. Use gemini mcp add, or edit settings.json yourself. The command defaults to the current project; add --scope user for every project:

gemini mcp add --transport http --scope user gridiron-data https://api.gridirondata.com/mcp

Or add this to ~/.gemini/settings.json (all projects) or .gemini/settings.json (one project). httpUrl is Gemini CLI's key for a Streamable HTTP server (url means SSE):

{
  "mcpServers": {
    "gridiron-data": {
      "httpUrl": "https://api.gridirondata.com/mcp"
    }
  }
}

Then sign in with /mcp auth gridiron-data as above.

Can I use my API key instead of a browser sign-in?

Yes, which is the way to go on a headless machine. Add the key as a header (your key is on your dashboard):

gemini mcp add --transport http --scope user \
  --header "Authorization: Bearer YOUR_KEY" \
  gridiron-data https://api.gridirondata.com/mcp

or in settings.json:

{
  "mcpServers": {
    "gridiron-data": {
      "httpUrl": "https://api.gridirondata.com/mcp",
      "headers": { "Authorization": "Bearer YOUR_KEY" }
    }
  }
}

If you installed the extension, uninstall it first (gemini extensions uninstall gridiron-data-mcp) so there's only one gridiron-data server.

What about the Gemini app (gemini.google.com)?

Google's Gemini app can add custom apps by MCP server URL, but Google limits it to personal Google Accounts of people 18 or over in the US, in English, with Keep Activity on, and you add it from the web app (Settings → Connected Apps → Custom apps → Add a custom app). Google's help page lists sign-in through the server's own OAuth and no API key option.

We haven't confirmed GridIron Data sign-in from the Gemini app yet. If it stops with "redirect URI not allowed", use Gemini CLI for now and email info@gridirondata.com so we can add it. Google AI Studio has no documented way to add an MCP server.

What can I ask Gemini?

Ask in your own words; the assistant picks the tool. A few that work well:

  • "What are the top 10 WR projections this week in PPR?"
  • "Compare Bijan Robinson and Jahmyr Gibbs: projections this week and snap share over the last four weeks." (Basic)
  • "Any injury news on Malik Nabers this week?" (Basic)
  • "Which teams are on bye this week, and which of my players does that hit: Josh Allen, Puka Nacua, Brock Bowers?" (Basic)
  • "What's the probability Drake Maye goes over 245.5 passing yards this week?" (Pro)

A free GridIron Data account answers player lookups and this week's projections. Stats, snap share, news, matchups, rest-of-season projections, the schedule and other weeks need Basic ($5/month or $45/year). Prop probabilities, defense vs position, betting lines, the injury-changes feed, depth charts and inactives need Pro ($29/month or $249/year), the betting plan. A question outside your plan comes back with the plan it needs, and the assistant tells you. See plans. Prop probabilities are a model estimate, not betting advice.

Player names, positions and ids are matched case-insensitively. Scoring is PPR unless you ask for half-PPR or standard. All 21 tools are listed on the AI assistant setup hub.

Troubleshooting

  • gemini extensions install fails inside Gemini. Install isn't supported in Gemini CLI's interactive mode. Exit and run it from your shell.
  • Sign-in doesn't open or never finishes. OAuth in Gemini CLI needs a local browser and a localhost callback. Over SSH or in a container, use the API key header instead.
  • /mcp shows gridiron-data twice. You added it both by extension and in settings.json. Keep one.
  • Gemini guesses player IDs. Ask it to search first ("find the player ID for Kenneth Walker"). The extension's GEMINI.md tells it to; settings.json setups don't have that file.
  • Sign-in page says the link expired. The sign-in has 15 minutes. Start the connection again from your assistant.
  • Asked to sign in again. You regenerated your API key, your plan ended, or the connection went unused for 30 days. Reconnect and sign in.
  • "Not available on this account's current plan". That question needs Basic or Pro. The reply names the plan; see plans.

Frequently asked questions

Can Gemini get NFL fantasy football data?

Yes, through Gemini CLI. Install the GridIron Data extension with gemini extensions install https://github.com/avansledright/gridiron-data-mcp and sign in, and Gemini can pull weekly projections, stats, snap share, news, injuries and player-prop probabilities from GridIron Data's hosted MCP server.

Does it work in the Gemini app or Google AI Studio?

The Gemini app can add custom MCP apps for eligible personal accounts in the US, but GridIron Data sign-in from the Gemini app isn't confirmed yet. Google AI Studio has no documented way to add an MCP server. Gemini CLI works today.

What does the extension install?

Nothing that runs on your machine. It registers the hosted server URL (https://api.gridirondata.com/mcp) and adds a GEMINI.md context file with the player ID format and scoring options. The source is public at github.com/avansledright/gridiron-data-mcp.

Can I use it on a headless server?

Yes, with your API key as an Authorization: Bearer header instead of the browser sign-in.

Is it free?

A free GridIron Data account answers player lookups and this week's projections. Stats, snaps, news and other weeks need Basic ($5/month or $45/year); prop probabilities, defense vs position and betting lines need Pro ($29/month or $249/year).

Using a different assistant?

Every assistant connects to the same server, https://api.gridirondata.com/mcp. The AI assistant setup hub compares them.