"Я уже с ним договорился."
Translation:I already came to an agreement with him.
that is the only thing that should be accepted. 'I already agreed "to it" with him.' is simply wrong.
Most certainly not. "I already agreed with him" means "Я уже с ним согласился".
"Договорился" implies some form of negotiation or interaction.
"Согласился" does not imply anything other than than a nod (or even a mental agreement with someone else's opinion). Neither does "agreed" without any additional qualifiers.
So, no, "I already agreed with him" is in general a poor translation of the original Russian sentence. It can work in some contexts, but it is most certainly not " the only thing that should be accepted".
Not quite. Russian "договорился" сan mean "to come to an agreement" (formal or not) or "to agree on something" (but not with something - that's where English "to agree" fails as possible a translation). E.g. you can use Russian "договориться" to describe reaching an agreement on a meeting place while planning to go out. Certainly no paper agreement is implied here.
Is this translation correct or not? None seem to have explicitly replied...
I already gave a detailed answer (just above) explaining why it isn't. It may work in some contexts, but it is not a good translation in general. Please read earlier threads before posting (repeatedly!).
Russian "Я уже с ним договорился" may or may not imply any business dealings or reaching a compromise, which is how I would interpret "We've made a deal". Its meaning is much broader. You can use the Russian sentence to indicate that the two of you have agreed on a pub where you plan to watch a game tonight. "Making a deal" can hardly be used in this context.
The range of meanings of English "to agree" certainly overlaps with that of Russian "договориться/договариваться" (perfective/imperfective).
«договориться» means coming to an agreement that both parties are more or less OK with through negotiation/bargaining etc. This perfective verb means that the result has been reached.