# NousResearch/hermes-agent · Fix misplaced system/marker messages causing HTTP 400 errors

## Open now

- Nothing open on GitHub.

These issues and fixes address two related problems: system messages appearing mid-conversation instead of at the start, and model-switch markers using role='system' mid-conversation, both causing HTTP 400 errors on strict providers like vLLM and Qwen.

## TL;DR

- 3 member(s): 0 open issue(s), 1 closed issue(s), 0 open PR(s), 0 merged PR(s), 2 PR(s) closed without merging.
- No fix has been merged to main; one or more PRs were attempted (see below).
- **Recommended:** review the prior/competing PR(s) below. A fix was attempted but not merged; your case may extend or revive that work.

## Maintainer resolution verdict

- Internal-tracker verdict over this cluster's issue members: `unresolved`. 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evidence (`STRUCTURAL_SPANNING`): every member is connected by structural evidence: shared changed files, or a closing/superseded reference.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 `0.67`: 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

- #20866: \[Bug\]: 400 format_error on Qwen3.6-27B — "System message must be at the beginning" in auxiliary tasks

## Prior & competing PRs

- **#20913: fix(auxiliary): ensure system messages precede other roles before LLM call**. closed without merge
  - maintainer direction: category `uncategorized`; implication `needs_llm`; refs `#20866`
- **#22624: fix(auxiliary-client): hoist misplaced system messages to front before dispatch (#20866)**. closed without merge
  - maintainer direction: category `silent_close`; implication `active`

## Fix status

- No merged fix on record.
- Subsystem: `agent`