rettangoli-ansi-json ships a schema at:

node_modules/rettangoli-ansi-json/schemas/ansi-json-v1.schema.json

{
  "$schema": "./node_modules/rettangoli-ansi-json/schemas/ansi-json-v1.schema.json",
  "content": [
    { "text": "Hello", "style": { "fg": "cyan", "bold": true } }
  ]
}

• content (required): array of render nodes.
• styles (optional): named style dictionary.
• version (optional): currently "1.0".

• Named colors (red, brightBlue, default).
• Hex (#rrggbb).
• RGB string (rgb(255, 0, 0)).
• 256-color index (0-255).