curl --request GET \
  --url https://api.retellai.com/v2/list-test-case-definitions \
  --header 'Authorization: Bearer <token>'

{
  "pagination_key": "<string>",
  "has_more": true,
  "items": [
    {
      "name": "<string>",
      "response_engine": {
        "type": "retell-llm",
        "llm_id": "<string>",
        "version": 0
      },
      "user_prompt": "<string>",
      "metrics": [
        "<string>"
      ],
      "dynamic_variables": {},
      "tool_mocks": [
        {
          "tool_name": "<string>",
          "input_match_rule": {
            "type": "any"
          },
          "output": "<string>",
          "result": true
        }
      ],
      "llm_model": "gpt-4.1",
      "test_case_definition_id": "<string>",
      "type": "simulation",
      "creation_timestamp": 123,
      "user_modified_timestamp": 123
    }
  ]
}