Is a mandate (Wakala) valid if the object of the transaction is unspecified?

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A mandate is invalid if the object of the transaction is not known (ma'lum). If one says, 'I appointed you as my agent for everything,' or 'for everything small and large,' or 'for every transaction permitted to me,' the mandate is invalid. This is the view held by Abu Hanifa and Al-Shafi'i. The basis for invalidity is the great risk (gharar) and significant danger involved, as such a mandate encompasses giving away one's wealth, divorcing one's wives, freeing one's slaves, and marrying numerous women, which would necessitate substantial dower payments and vast prices, leading to immense harm.