- Added `keepBoundaryId` and `cacheWarmSuffixTokens` guards to `pruneToolOutputs` and `pruneSupersededToolResults` so superseded/useless results sitting in the already-sent cached prefix are no longer rewritten mid-session, with new `computeMessageSuffixTokens`/`resolveBoundaryIndex` helpers.
- Added a `keepBoundaryId` floor to `collectShakeRegions` so shake skips entries summarized away by the latest compaction.
- Threaded `firstKeptEntryId`, `PRUNE_CACHE_WARM_SUFFIX_TOKENS` (8k) and `PRUNE_IDLE_FLUSH_MS` (90m, above the 1h cache TTL) from `#pruneToolOutputs`, `#pruneStaleToolResults` and `shake` in `agent-session.ts`.
- Added six boundary tests in `supersede-prune.test.ts` covering warm-prefix protection, tail-case pruning, and the pre-boundary floor.
can1357
dcb16d86f6