Documentation / Guides

Give an OpenAI or Anthropic model a chess engine

tool-calling definition and a budget guard

Tool definition

{
  "name": "evaluate_position",
  "description": "Evaluate a chess position with Stockfish. Returns the best move, evaluation in centipawns from White's view, and the top lines. Depth 14 is enough for move choice; use 20+ only when asked for deep analysis.",
  "input_schema": {
    "type": "object",
    "properties": {
      "fen": { "type": "string" },
      "depth": { "type": "integer", "minimum": 1, "maximum": 22, "default": 14 },
      "multipv": { "type": "integer", "minimum": 1, "maximum": 5, "default": 1 }
    },
    "required": ["fen"]
  }
}

Budget guard

Models will happily ask for depth 30. In your tool handler, call GET /v1/price first and refuse anything over a per-call ceiling, returning the problem text to the model so it lowers the depth itself.

Get a key with one call: POST /v1/signup {"email":"you@example.com"}. Free plan, depth 14, 2,000 units a day.