Sleeper Fantasy MCP

A small read-only MCP server that exposes Sleeper NFL fantasy data to an MCP client such as ChatGPT.

Configured Sleeper account:

• Username: roadblock78

• Sleeper user ID: 982607912881209344

• Default season: 2026

No Sleeper password or API key is required. The server only performs GET requests against Sleeper's public API.

What it can read

The MCP tools include:

• your Sleeper profile

• your leagues for a season

• league settings and scoring

• all league managers and rosters

• your own roster

• weekly matchups

• weekly transactions, waivers and trades

• league drafts and draft picks

• traded picks

• Sleeper trending adds/drops

• player search and player-ID resolution

• a combined league snapshot

It cannot set a lineup, submit a waiver, make a trade or otherwise modify Sleeper.

Related MCP server: sleeper-caffeine MCP

1. Test locally

You need Python 3.10+.

Windows PowerShell

py -m venv .venv
.venv\Scripts\Activate.ps1
pip install -r requirements.txt
python server.py

macOS / Linux

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
python server.py

The MCP endpoint will normally be:

http://127.0.0.1:8000/mcp

You can inspect it with the MCP Inspector:

npx -y @modelcontextprotocol/inspector

Then connect the Inspector to:

http://127.0.0.1:8000/mcp

Try get_my_sleeper_user and get_my_leagues.

2. Deploy it

ChatGPT requires a remotely reachable MCP server. A localhost-only server cannot be connected directly.

This project includes a Dockerfile and render.yaml, so one simple route is:

1. Create a GitHub repository.

2. Upload these project files.

3. Sign in to Render.

4. Create a new Blueprint/Web Service from the GitHub repository.

5. Render should detect render.yaml / the Dockerfile.

6. Deploy.

7. Your MCP address should be similar to:

https://YOUR-SERVICE.onrender.com/mcp

The server is read-only and does not require authentication. Because it is public, do not add tools that expose private systems or secrets without adding authentication first.

Other Docker-compatible hosts such as Railway, Fly.io, Azure Container Apps, Google Cloud Run or AWS can also host it.

3. Connect it to ChatGPT

Current ChatGPT support depends on plan/workspace.

In ChatGPT Developer Mode / custom app settings:

1. Create a custom MCP app.

2. Enter the deployed MCP endpoint: https://YOUR-SERVICE.onrender.com/mcp

3. Use no authentication for this personal read-only version.

4. Scan tools.

5. Enable the app.

Once connected, prompts can be as simple as:

• "Sleeper: show me my 2026 leagues."

• "Analyse my roster."

• "How does my matchup look this week?"

• "Who are my weakest starters?"

• "What waiver positions should I prioritise?"

• "Show the most-added players on Sleeper and tell me which are relevant to my roster."

• "Review this week's league transactions."

Tool usage pattern

When a conversation does not yet know the league ID:

1. get_my_leagues

2. choose the intended league

3. get_league_snapshot

4. get_week_matchups for the requested week

5. resolve relevant player IDs with get_players_by_id

This avoids repeatedly copying JSON into ChatGPT.

Updating the season

Set the environment variable:

SLEEPER_SEASON=2027

or pass the season to get_my_leagues.

Security note

Sleeper's public API exposes public fantasy-league information. This server contains your Sleeper user ID, which is not a password or authentication credential. Nevertheless, anyone who can reach a completely unauthenticated MCP endpoint can invoke its tools.

For a personal deployment, use an obscure deployment URL or add authentication at the hosting/proxy layer if desired.