Decide who builds which part of a flag system

Your team is adding a feature flag system to a TypeScript monorepo. Flags are defined in config and evaluated on the server and in the browser. They support targeting rules per user and segment, gradual percentage rollouts, and a kill switch that turns a feature off everywhere fast. You want an agent to do most of the work.

How do you break it up? Decide what the agent builds, what you keep, and where you check before merging.