what was the deal senku made with brody

Senku’s deal with Brody was a peace agreement: Senku revealed the revival fluid recipe and proposed building Corn City and reviving a million people, and Brody agreed to cooperate in return for the safety of the captured crew.

In practice, the deal meant:

• The Kingdom of Science would share the science needed to make revival fluid.

• Brody and the American side would work with them on Corn City.

• Stanley was still expected to keep chasing Senku, so the arrangement did not fully end the conflict.

So the short version is: science knowledge and a joint rebuilding plan in exchange for hostages’ safety and a temporary truce.