The Now field must be part of the terms, otherwise other terms cannot be interpreted. This could have been inferred, but now it's explicit. All times are measured in seconds. UTC 1 Jan 1970. All money is measured in compucredits, a fictitious unit.
All computational work is measured in computrons, a fictitious unit.
For now, a computron is nominally one clock cycle, but a more accurate measure may be defined in the future. All floats are non-negative unless otherwise specified. We'll define these later. If reaction is accept, the terms of the offer become a contract binding on both parties. See the executor interface.