I am surprised at 'removes actual tool calls/results, tool output'. Your approach with /prune seems to be 'keep the WHAT, remove the HOW (we got here)'. I would have thought that the HOW contains some useful signal.
The how is important, but I've found all of the decisions, question, answers, and results are the most important and the tool calls themselves secondary. When necessary, the tool calls can be deleted without much being lost.