OpenAI API tool response reportedly includes the full compaction item when the first action after compacting is a tool call

A post shares a quoted account of “GhostCompact”: when the model’s first action after compacting was a tool call, the API reportedly billed only for post-compaction tokens, while the tool call response still contained the full compaction item. The poster calls it an example of information leakage and says they are unsure what passive control could address it.