# Chess Notation Tools – PGN Header Parser & Validator

> Chess Notation Tools – PGN Header Parser & Validator is a paid API for AI agents from chess-notation.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Parses PGN tag pairs, validates the Seven Tag Roster, checks result token and date format, and counts moves in the movetext.

## Facts

- Endpoint: GET https://chess-notation.x402tookit.com/pgn-headers?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/chess-notation-tools-pgn-header-parser-validator-e86167db
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_SnFdIWeO3188SmHyU6zgm

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 chess-notation-tools-pgn-header-parser-validator-e86167db
```

Example prompt: Can you parse and validate the headers in this PGN — I want to know if the Seven Tag Roster is complete, whether the date and result token look correct, and how many moves are in the game: '[Event "World Championship"][Site "London"][Date "2024.11.01"][Round "1"][White "Carlsen, Magnus"][Black "Nepomniachtchi, Ian"][Result "1-0"] 1. e4 e5 2. Nf3 Nc6 1-0'

## When to prefer this

Use this endpoint when you need to validate or extract structured metadata from PGN chess game headers — especially to check Seven Tag Roster completeness, verify date/result format compliance, or count moves before storing or displaying a game. Prefer this over general text parsing when working specifically with PGN-formatted chess data.

## Known failure modes

- PGN string exceeds 6000 character limit — request rejected
- Malformed or empty PGN input causes null fields in output
- PGN with no tag pairs returns empty tags object and missing roster tags list
- Non-standard or custom tag names may not be checked against the Seven Tag Roster
- Ambiguous or missing result token returns null resultInMovetext
- Payment failure (x402) prevents call from completing

## How this service works

Parse PGN tag pairs, check the Seven Tag Roster, result token and date format, and count the moves in the movetext.

## Output

Returns a structured object containing: extracted tag key-value pairs (Event, Site, Date, White, Black, Round, Result), total tag count, list of missing Seven Tag Roster tags, a boolean indicating whether the Seven Tag Roster is complete, the result token found in the movetext, full and half move counts, first few moves, a validation verdict (pass/fail/warn), human-readable reasons for any issues, a summary string, and flags for degraded service or unchecked fields.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "pgn"
     ],
     "properties": {
      "pgn": {
       "type": "string",
       "description": "A PGN game or just its tag-pair header (up to 6000 characters)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "tags": {
       "type": [
        "null",
        "object"
       ],
       "properties": {
        "Date": {
         "type": [
          "null",
          "string"
         ]
        },
        "Site": {
         "type": [
          "null",
          "string"
         ]
        },
        "Black": {
         "type": [
          "null",
          "string"
         ]
        },
        "Event": {
         "type": [
          "null",
          "string"
         ]
        },
        "Round": {
         "type": [
          "null",
          "string"
         ]
        },
        "White": {
         "type": [
          "null",
          "string"
         ]
        },
        "Result": {
         "type": [
          "null",
          "string"
         ]
        }
       }
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ]
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "tagCount": {
       "type": [
        "null",
        "number"
       ]
      },
      "fullMoves": {
       "type": [
        "null",
        "number"
       ]
      },
      "halfMoves": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
     
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chess-notation-tools-pgn-header-parser-validator-e86167db/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from chess-notation.x402tookit.com](https://www.zero.xyz/host/chess-notation.x402tookit.com/llms.txt)