Your first ExecuteScript call

ExecuteScript is a freeform Domain API action. The request supplies JavaScript source directly; no script record or parameter schema is created.

Send an HTTP POST with the source as the plain-text body:

POST /api/domain/odata/ExecuteScript
Content-Type: text/plain
Authorization: Bearer <access-token-with-exec-scope>

const customers = Domain.Crm.Sales.CustomersRepository.query(
    { active: true }, { fetch: 10 });
console.log("Found " + customers.Count + " customers.");

The script's console.log message appears in the response's console field, alongside execution metadata. This action does not return a managed-script parameters/returnValue envelope: the request contains code, not a stored definition with declared inputs. There is no automatic subject or args object. A standalone call does not implicitly commit Domain changes. The calling application needs the exec scope, and the instance needs the X21 Advanced BPM license.

See the ExecuteScript operation reference for transaction handling and the complete response. More requests are in ExecuteScript examples.