# Saylor Innovations Chess Position Evaluator

> Saylor Innovations Chess Position Evaluator is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Evaluates a chess position given in FEN notation using Stockfish via the Lichess cloud engine, returning analysis lines and depth

## Facts

- Endpoint: GET https://saylorinnovations.com/api/chess/eval?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/saylor-innovations-chess-position-evaluator-ddaa4c09
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_B8kyUUlaWmbYCPt6Z4sHv

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability saylor-innovations-chess-position-evaluator-ddaa4c09
```

Example prompt: Can you evaluate this chess position for me: rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1 — I want to see the best lines according to Stockfish.

## When to prefer this

Choose this endpoint when you need fast, cloud-based Stockfish chess analysis without running a local engine. It is ideal for quickly checking well-known or frequently-played positions that are likely cached in the Lichess cloud. Best for agents needing on-demand chess analysis at low cost per query ($0.001 USDC). If you need guaranteed analysis of any arbitrary position including novel ones not yet cached, a dedicated local Stockfish instance may be more reliable.

## Known failure modes

- Invalid FEN string returns an error or found:false
- Position not cached in Lichess cloud returns found:false with no lines
- Missing fen query parameter may cause a bad request
- Very exotic or illegal positions may not be found in the cloud cache
- Rate limiting or payment failure returns a 402 or 429 status

## How this service works

Chess Position Evaluation (Stockfish via Lichess cloud). Chess position evaluation from Stockfish via the Lichess cloud: up to 5 best lines with moves, evaluation in pawns or mate-in-N, depth and a plain-language verdict.

## Output

Returns a JSON object with a 'found' boolean indicating whether the position was in the Lichess cloud cache, an optional 'depth' number indicating how deeply the position was analyzed, and a 'lines' array containing engine analysis lines with candidate moves and evaluations.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "POST",
      "PUT",
      "PATCH",
      "DELETE",
      "HEAD"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "fen": {
       "type": "string",
       "description": "position in FEN (query)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "found"
     ],
     "properties": {
      "depth": {
       "type": "number"
      },
      "found": {
       "type": "boolean"
      },
      "lines": {
       "type": "array",
       "items": {
        "type": "object"
       }
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/saylor-innovations-chess-position-evaluator-ddaa4c09/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from saylorinnovations.com](https://www.zero.xyz/host/saylorinnovations.com/llms.txt)