A session groups the nodes that share a root session id, with sub-agent transcripts folded into their parent. Each entry carries live memory and signal counts plus a generated title and summary, which fall back to the opening message until the cached summary is written. Use after and before to bound the activity window.
This route requires the read scope.A missing or invalid credential returns 401 authentication_error. A valid credential without the scope returns 403 permission_denied, and the problem body names the exact scope required.