Is it permissible to conclude a Mudarabah partnership contract on the condition that the effort provider (worker) bears no loss in the capital or profit?

The agent's hand in a Mudarabah (profit-sharing) contract is a hand of trust (amanah), not a hand of guarantee (daman). Therefore, he does not bear the loss in profit or capital unless there is an act of transgression (ta'addi) or negligence (taqseer) on his part. Stipulating his guarantee is invalid. As for stipulating that he does not bear any anticipated loss, this is a matter of tahseel al-hasel (stating the obvious) and does not affect the validity of the contract.