Does an employee sin for having free time during work, and does an employer sin if he assigns the employee tasks outside the agreed-upon nature of his job?

In Islamic jurisprudence, a secretary is considered a specific hired hand (ajīr khāṣṣ) who earns their wage by making themselves available for the agreed-upon duration, even if they are not assigned tasks. The employer is not permitted to engage them in work other than what was stipulated in the contract, except with their consent. This is based on the Almighty's saying: "O you who have believed, fulfill [all] contracts," and the Prophet's (peace be upon him) saying: "Muslims are bound by their conditions regarding what is permissible."