runjanus: a rehearsal room for agents with spending power

Field notes

The workflow separates rehearsal from execution: reads use recorded responses or a read-only replica, while writes are captured rather than sent. The real run is then compared against five surfaces—tool calls, files, network, spend, and tokens—with deviations held or blocked according to the operator’s decision. The examples show a four-call, $48.00 refund preview, a 10% spend tolerance, and receipts stored as JSON with a SHA-256 digest.