is myIn these examples, it is followed by a masculine singular noun, so meu means 'my': é meu agente = 'is my agent'. On its own, é meu usually means 'it's mine'. The form changes with gender and number: é minha, são meus, são minhas.
is mineUsed to say that something belongs to the speaker. The possessive changes to match the gender and number of the thing owned: for example, é minha, são meus, são minhas.