depot-mcp

An MCP server that gives LLMs structured access to Warhammer 40,000 (10th edition) game data: faction lists, unit datasheets, stratagems, detachments and enhancements. The data comes from a depot instance, which in turn builds it from Wahapedia's CSV exports.

Models answering rules questions from memory get stats wrong constantly. Giving them lookup tools instead of trivia recall fixes that: the model calls get_datasheet("tyranids", "Barbgaunts") and quotes the actual sheet.

Tools

All tools are read-only. HTML in the source data is flattened to plain text before it reaches the model.

Related MCP server: Pokemon Showdown MCP Server

Getting the data

The server reads depot's generated JSON (index.json, per-faction faction.json, per-unit datasheet files). Point it at either:

1. A running depot instance (DEPOT_DATA_URL): any depot deployment serves its data under /data/. If you self-host depot, use that URL.

2. A local directory (DEPOT_DATA_DIR): generate the JSON yourself with depot's CLI, no web app needed:

git clone https://github.com/fjlaubscher/depot
cd depot
pnpm install
pnpm --filter @depot/core build && pnpm --filter @depot/cli build
pnpm --filter @depot/cli start   # downloads Wahapedia CSVs, writes JSON
# data is now in packages/cli/dist/data

Set exactly one of the two variables. Data is loaded lazily on the first tool call and cached. Restart the server to pick up refreshed data.

Running

With uv:

DEPOT_DATA_DIR=/path/to/depot/packages/cli/dist/data uv run depot-mcp

With Docker:

docker build -t depot-mcp .
docker run -p 11437:11437 \
  -e MCP_HOST=0.0.0.0 \
  -e DEPOT_DATA_URL=https://your-depot-instance.example \
  depot-mcp

Configuration

Transport is streamable HTTP at /mcp. With both MCP_AUTH_TOKEN and MCP_OIDC_ISSUER empty the server runs unauthenticated. Only do that on a trusted network, and don't expose it to the internet without one of the auth modes configured.

Prometheus metrics

The server exposes a /metrics endpoint in Prometheus exposition format (unauthenticated, for internal scraping). Metrics include request counts and latency per tool, OIDC verification timing, data load duration, and datasheet cache hit/miss rates.

Connecting clients

Claude Code:

claude mcp add depot \
    --transport http \
    --url http://localhost:11437/mcp \
    --header "Authorization: Bearer $MCP_AUTH_TOKEN"

Open WebUI: Admin Settings → External Tools → add an MCP connection with URL http://<host>:11437/mcp, auth type Bearer, and your token.

Any other MCP client: standard streamable-http endpoint, JSON-RPC over POST:

curl -X POST http://localhost:11437/mcp \
    -H "Authorization: Bearer $MCP_AUTH_TOKEN" \
    -H "Content-Type: application/json" \
    -H "Accept: application/json" \
    -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

Development

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

Tests run against a committed subset of real depot output in tests/data, so they need no network and no running depot.

License

MIT. This is a fan project: not affiliated with, endorsed by, or sponsored by Games Workshop Limited. Game data comes from Wahapedia's public exports via depot; the underlying game rules are Games Workshop's intellectual property.