What is a Wyoming series LLC and why file one master?

Sol, a solo founder, expected that launching a dozen agents meant a dozen filings — a dozen entities, a dozen fees, a dozen renewals. Instead she files once. She forms a single master Wyoming series LLC: one entity on the state's record, one EIN from the IRS, one registered agent listed to receive service. Sol is the sole Member and Manager of the master, which is the thing the law can name. Under that master, individual series are adopted later, one at a time, as the work appears. When Sol brings on her software agent Rupert, Rupert is run inside a series — never a legal actor itself, signing only as an authorized signer with capped authority, with Sol standing behind every series as the human Member and Manager. The master is filed once; the series are adopted as needed.