# NousResearch/hermes-agent · prefix cache preservation across compaction rebuilds

## Open now

- Nothing open on GitHub.

These items address how the prefix cache and prompt prefix are maintained during memory compaction rebuilds, including pinning workspace snapshots and MEMORY blocks to reduce cache loss across sessions.

## TL;DR

- 4 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 1 merged PR(s), 2 PR(s) closed without merging.
- A fix was merged to main in PR #104455. Verify it addresses your case.
- **Recommended:** read PR #104455 (and any competing PRs below) before filing. Confirm the merged change covers your symptom.

## Maintainer resolution verdict

- Internal-tracker verdict over this cluster's issue members: `resolved` · deciding PR(s): `pr-104455`. This is distinct from the fix status above. Weigh it yourself.

## How this cluster was grouped

- Link evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.
- Pairwise link density `0.50`: the share of member pairs that carry a link, counting a structural link in full and a relevance-only link at 0.36. `1.00` means every pair is linked.

## Closed / duplicate issues

- #103326: perf(prefix-cache): pin built-in MEMORY block at the end of the volatile band to cap compaction-rebuild cache loss

## Prior & competing PRs

- **#104455: Compaction rebuilds keep the prefix cache in coding sessions: the workspace snapshot is pinned per session instead of re-probed (#103326, salvage of #103358 by @JoaoMarcos44)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`
  - files: `agent/agent_init.py`, `agent/coding_context.py`, `agent/system_prompt.py`, `run_agent.py`, `tests/test_compaction_prompt_rebuild.py`, `tui_gateway/methods_session.py`
- **#103358: perf(prefix-cache): pin session-start workspace snapshot across compaction rebuilds**. closed without merge
  - maintainer direction: category `merged_via`; implication `superseded`; refs `#104455`, `#103331`, `#103566`, `#103326`
- **#103566: fix(agent): preserve the prompt prefix across memory reloads**. closed without merge
  - maintainer direction: category `merged_via`; implication `superseded`; refs `f58fcc8118d9db092ad60d363d4a28520e08ac5a`, `#103331`

## Fix status

- Merged to main in PR #104455 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-09-06`.