Private Long-Form Generation via Semantic Release

Reports based on private records often ask different questions about the same underlying quantities. Acquiring those quantities separately for each question divides the privacy budget across repeated computations. In this paper, we propose Semantic Release, which acquires shared task states once and reuses them throughout a report. Public question dependencies specify the required states. Record-level mechanisms release them into a typed ledger, a public compiler computes answers, and a writer expresses those answers without further private access. Conditional zCDP composition bounds the privacy cost of the resulting transcript by the acquisition budget. We evaluate a Gaussian-view instance on LongWeave Sales Report 8K. Under the same statistical scope and total budget, report correctness increases from 20.96% with question-wise acquisition to 24.74% with shared releases, while answered rate remains similar. A budget sweep improves both acquisition and report correctness. Exact-view controls and a fidelity analysis show where gains are lost: questions can require unreleased statistics, noisy views can produce wrong answers, and the writer can fail to express a correct answer.