Built around the way agents work.
Most developer tools assume a person at the keyboard. discern treats your coding agent as its day-to-day operator, and most of what it does for the agent happens out of your sight.
Every session opens already briefed by your project's compiled instructions. One call reports what is true right now and the next valid step, so the agent never rebuilds the picture from a long transcript.
Results come back bounded, so the agent spends its context on your change rather than on the tool. A failed check returns the evidence and a command to reproduce it, and a refusal always names a way forward. The agent operates; you still decide what lands.