Claude · Schema

CountTokensRequest

Artificial IntelligenceChatbotConversational AIGenerative AILarge Language ModelsMachine LearningNatural Language Processing

Properties

Name Type Description
model string The model to use for token counting.
messages array Input messages to count tokens for.
system object System prompt to include in the token count.
tools array Tool definitions to include in the token count.
thinking object
View JSON Schema on GitHub

JSON Schema

claude-counttokensrequest-schema.json Raw ↑ 
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "#/components/schemas/CountTokensRequest",
  "title": "CountTokensRequest",
  "type": "object",
  "required": [
    "model",
    "messages"
  ],
  "properties": {
    "model": {
      "type": "string",
      "description": "The model to use for token counting.",
      "example": "claude-sonnet-4-6"
    },
    "messages": {
      "type": "array",
      "description": "Input messages to count tokens for.",
      "items": {
        "$ref": "#/components/schemas/MessageParam"
      },
      "minItems": 1,
      "example": []
    },
    "system": {
      "description": "System prompt to include in the token count.",
      "oneOf": [
        {
          "type": "string"
        },
        {
          "type": "array",
          "items": {
            "$ref": "#/components/schemas/TextBlockParam"
          }
        }
      ],
      "example": "example_value"
    },
    "tools": {
      "type": "array",
      "description": "Tool definitions to include in the token count.",
      "items": {
        "$ref": "#/components/schemas/Tool"
      },
      "example": []
    },
    "thinking": {
      "$ref": "#/components/schemas/ThinkingConfig"
    }
  }
}