curl https://api.platformdtc.com/api/v1/agent/v1/whoami \
  -H "X-Agent-Key: sq_agt_xxx"
# { "data": { "kind": "api_key", "store_id": "…", "scopes": [ … ] } }

import requests

r = requests.get(
    "https://api.platformdtc.com/api/v1/agent/v1/whoami",
    headers={"X-Agent-Key": "sq_agt_xxx"},
)
print(r.json()["data"])

const r = await fetch(
  "https://api.platformdtc.com/api/v1/agent/v1/whoami",
  { headers: { "X-Agent-Key": "sq_agt_xxx" } },
);
console.log((await r.json()).data);