Sleeper Fantasy Football MCP 2026

An MCP server that helps an AI agent run a Sleeper fantasy football team from draft night through the championship. Sleeper is the read-only source of league state; recommendations, draft queues, decision history, and model data are stored locally in SQLite.

What it does

• Discovers your league, roster, and draft from one Sleeper username or user ID.

• Syncs rosters, drafts, picks, matchups, transactions, players, and league history.

• Imports public ffverse player crosswalks and current rankings without an API key.

• Best-effort fills projection/ADP gaps from Sleeper's public projection feed.

• Optionally enriches remaining gaps with FantasyPros or normalized third-party snapshots.

• Recommends draft picks and estimates who may survive to your next pick.

• Maintains a conflict-safe local draft queue.

• Optimizes lineups and analyzes waivers, FAAB, trades, and season strategy.

• Learns descriptive manager tendencies from historical league behavior.

• Preserves source snapshots, recommendations, actions, and outcomes for later evaluation.

The models expose their inputs and uncertainty. Heuristic survival, FAAB, and championship estimates are not presented as calibrated facts.

Related MCP server: @fantopy/fantopy-mcp

Requirements

• Python 3.12+

• uv

• A Sleeper username or user ID

FantasyPros is optional. The public ffverse feed is the preferred model-evidence source. Its rankings are distributed through the nflverse ecosystem by DynastyProcess and originate from FantasyPros consensus, so the server preserves that upstream lineage rather than double-counting the two feeds as independent evidence.

Setup

uv sync
cp .env.example .env

Edit .env:

FF2026_SLEEPER_USER_ID=your-sleeper-username
# Optional:
# FF2026_FANTASYPROS_API_KEY=your-api-key

Start the stdio MCP server:

uv run --env-file .env ff2026-mcp

State is stored in .data/ff2026.sqlite3. Credentials are read only from the environment and are excluded from source control.

MCP configuration

{
  "mcpServers": {
    "ff2026": {
      "command": "uv",
      "args": [
        "--directory",
        "/absolute/path/to/mcp-ff2026",
        "run",
        "--env-file",
        ".env",
        "ff2026-mcp"
      ]
    }
  }
}

First run

Ask the agent to perform these operations:

1. initialize_season discovers and stores the league, roster, and draft defaults.

2. get_season_context confirms the selection.

3. sync_ffverse imports the public player crosswalk and preseason rankings using week 0.

4. sync_sleeper_projections attempts free preseason projection and ADP fallback data.

5. get_provider_status reports unresolved player identities.

6. sync_league_history imports previous seasons for manager analysis.

ffverse's draft dataset contains ranks, not season point projections. Import a licensed projection feed with import_provider_snapshot, configure the optional FantasyPros API, or use the best-effort Sleeper-hosted projection fallback. Third-party evidence fills a missing player/metric/horizon only; matching native ffverse evidence remains authoritative. The weekly PPR rank-to-points field is retained as an explicitly labeled fallback rather than promoted to a native projection. Sleeper's projection URL is public but not part of its documented API, so refresh failures warn and preserve the last good evidence instead of blocking ffverse refreshes.

If the account has multiple leagues, initialize_season returns the choices instead of guessing.

During the draft

1. Run refresh_decision_inputs with week 0.

2. Read get_draft_state and stop if it reports stale data.

3. Use recommend_draft_pick and review the alternatives and survival ranges.

4. Update the local queue with set_draft_queue_entry.

5. Record the chosen action, sync the draft, and repeat.

No tool makes picks or other changes in Sleeper.

During the season

Refresh inputs each week, then use the lineup, waiver, trade, value-change, simulation, and season strategy tools as needed. Record actions and outcomes so calibration reports can evaluate the system prospectively.

Create a transactionally consistent backup with:

uv run --env-file .env ff2026-backup

Development

uv run ruff format --check .
uv run ruff check .
uv run mypy
uv run pytest

Detailed design and contracts:

• Architecture

• Data model

• MCP tool surface

• Implementation plan

• Architecture decision

Additional data sources must be licensed for your use. Boris-style tiers are treated as a FantasyPros-derived benchmark, not as independent evidence.