{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://raw.githubusercontent.com/api-evangelist/merge/refs/heads/main/json-schema/gateway-response-schema.json",
  "title": "GatewayResponse",
  "description": "An LLM response returned by the Merge Gateway after routing the request to the selected execution vendor.",
  "type": "object",
  "properties": {
    "id": { "type": "string", "description": "Gateway-issued response identifier." },
    "model": { "type": "string", "description": "Logical model alias requested (e.g. claude-4.7-opus, gpt-4o)." },
    "vendor": { "type": "string", "description": "Execution vendor that ultimately served the request (e.g. anthropic, openai, google)." },
    "provider": { "type": "string", "description": "Model family provider, may match vendor." },
    "created_at": { "type": "string", "format": "date-time" },
    "output": {
      "type": "array",
      "description": "Output content blocks (text, tool_use, etc.).",
      "items": { "type": "object" }
    },
    "usage": {
      "type": "object",
      "properties": {
        "input_tokens": { "type": "integer" },
        "output_tokens": { "type": "integer" },
        "cached_input_tokens": { "type": "integer" }
      }
    },
    "routing": {
      "type": "object",
      "description": "Routing metadata explaining selection.",
      "properties": {
        "policy": { "type": "string" },
        "strategy": { "type": "string" },
        "tags": { "type": "array", "items": { "type": "string" } }
      }
    }
  },
  "required": ["id", "vendor", "output"]
}