Returns one node's text with its public citations, child handles, related handles and a cite-as line; variant chooses full (the default: lede, conditions, reasoning) or terse (the lede alone) at the same price. The free layer (the equation, the branch roots, value/15s and the decision-method nodes, marked free in bf_catalogue) costs nothing; every other node costs its catalogue price ($0.02 to $0.05, USDC on Base over x402), charged once per call and only when the text is returned. Call it with a path from bf_catalogue when the user's question needs that node's reasoning or decision rule; read the free parent before buying a child, and use bf_resolve when the question is broad enough to take several nodes. Do not call a paid path to see what it contains: the catalogue line says what it covers; and do not use it to run a rule on numbers, which is bf_apply_decision.