Keep the stable system prompt mode-agnostic and project mode, approval policy, and tool taxonomy as request-time runtime metadata. This avoids mutating stored history while preserving provider chat-template compatibility.
Harvested from PR #2687 with stewardship turn-metadata cache tests preserved. The replan replay guard remains <= 2, and cache inspect now asserts tool-result budget metadata for both deduplicated=false and deduplicated=true.
(cherry picked from commit 77943304e637545b441ac135f06977065c4b350f)
LeoAlex0
1f9f860a3e