# NousResearch/hermes-agent · MoA aggregator prompt cache billing and routing fixes

## Open now

- Nothing open on GitHub.

Multiple fixes targeting how the MoA aggregator handles prompt cache identity, routing, and persistence across tool steps and iterations. A related issue documents unexpected re-billing behavior when tool history grows and cache fails to stay pinned to the system prompt.

## TL;DR

- 6 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 3 merged PR(s), 2 PR(s) closed without merging.
- A fix was merged to main in PR #113175. Verify it addresses your case.
- **Recommended:** read PR #113175 (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-115606`. 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evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.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 `0.33`: 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

- #112358: MoA aggregator: prompt cache hits stay pinned to the system prompt; growing tool history re-billed every call (~$147 in 49 min)

## Prior & competing PRs

- **#113175: fix(moa): aggregator prompt cache no longer collapses to the system prompt on every tool step (#112358)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`; implication `superseded`
  - files: `agent/moa_loop.py`, `tests/agent/test_failover_identity.py`, `tests/agent/test_moa_aggregator_prefix_stability.py`, `website/docs/user-guide/features/mixture-of-agents.md`
- **#113784: fix(moa): Anthropic-wire aggregator keeps the cache prefix through the task on iteration 1 (closes remaining atoms of #112358)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`; implication `superseded`
  - files: `agent/anthropic_message_convert.py`, `agent/moa_loop.py`, `tests/agent/test_anthropic_adapter.py`, `tests/agent/test_moa_aggregator_prefix_stability.py`, `website/docs/user-guide/features/mixture-of-agents.md`
- **#115606: fix(moa): aggregator recovers from strict-alternation 400s per destination (closes remaining atoms of #112358)**. merged to main · fix tier `verified`
  - maintainer direction: category `merged`; implication `superseded`
  - files: `agent/chat_completion_helpers.py`, `agent/error_classifier.py`, `agent/moa_alternation.py`, `agent/moa_loop.py`, `agent/turn_failure_copy.py`, `tests/agent/test_error_classifier.py`, `tests/agent/test_moa_alternation_recovery.py`, `website/docs/user-guide/features/mixture-of-agents.md`
- **#112360: fix(moa): preserve Nous aggregator cache routing**. closed without merge
  - maintainer direction: category `implemented_elsewhere`; implication `superseded`; refs `026551488f3`, `170d616ca69`, `#112358`, `#113175`, `#113784`, `#113175`, `#113175`
- **#112400: fix(moa): reuse transport cache identity for Nous aggregator calls**. closed without merge
  - maintainer direction: category `implemented_elsewhere`; implication `superseded`; refs `026551488f3`, `170d616ca69`, `#112358`, `#113175`, `#113784`, `#113175`

## Fix status

- Merged to main in PR #113175 (cited above). No release data is tracked. Verify downstream.
- Fix last verified (merged) `2026-09-19`.