How do I interpret a variable that exists in JSON data?

({
    "messages": [
        {
            "role": "user",
            "content": "$var:f/prompts/history_prompt"
        }
    ],
    "model": "o1",
    "logprobs": false,
    "response_format": {
        "type": "text"
    },
    "stream": false,
    "user": "$var:f/ai_api_key/opanai-lab-p1-key"
})

({
    "messages": [
        {
            "role": "user",
            "content": "$var:f/prompts/history_prompt"
        }
    ],
    "model": "o1",
    "logprobs": false,
    "response_format": {
        "type": "text"
    },
    "stream": false,
    "user": "$var:f/ai_api_key/opanai-lab-p1-key"
})