cb481e2f2b
The phase-1 tool-result prune only runs inside compress(), which fires near 50% of the context window, so it never triggers on large-window models; old tool outputs then ride in history and are re-sent every turn. Add prune_tool_results_only(): the same no-LLM prune on a separate, low proactive_prune_tokens trigger, run as an elif to the compression branch. Opt-in (default 0), protects the recent tail by message count. Add the method to the ContextEngine base as a no-op default so pluggable engines inherit it safely (the post-tool-call path never AttributeErrors on a non-built-in engine); the built-in compressor supplies the real prune. Register both keys under the top-level compression config with defaults and document them.